Kathryn Kremnitzer and Siddhartha Shah FA15 Annotation Plans

OPTICAL PROPERTIES OF IMITATION GEMS, VARNISHES

RUBY, EMERALD CONFUSION HERE? START WITH EMERALDS VARYING ONE FACTOR.

RED COLORS. LONG HISTORY OF IMITATION GEMS.


IMITATION EMERALD
Trial 1: 16.10.2015 [see Siddhartha's field notes copied below]
Trial 2: schedule for 29.10.2015

BnF Ms Fr640, p100v

SUPPLIES

SAFETY:

-newspapers/wet paper towels (under mortar/pestle and wet p.t. for clean up)
-dust mask
-two layers of nitrile gloves (to be removed by inverting the gloves and avoiding contact with skin…tape also recommended to protect wrists/upper arms)
-hazardous waste container/bucket

INGREDIENTS:
3.54g quartz powder, fine
10.62g red lead
-3.54g potash
-oil (for cleaning tools used with lead)
wine (unspecified in Merrifield, assume to be red wine)


TOOLS/SUPPLIES
-copper sheet
-crucible/lid
-brick/something to block wind while measuring out ingredients
-torch and furnace
-paper towels, wet
-newspaper
-two palette knives (minimum)
-plastic spoon
-2-3 stainless steel scoop things
-glass plate/muller, thoroughly dry and clean
-scale
-beaker
-"rough" wool (unspecified in Merrifield)



PROCEDURE
SET UP
-Clean fume hood thoroughly
-lay out newspapers to cover entire surface and spread out wet paper towels, particularly in areas where there will be lead
-prepare the space: set out containers of ingredients (quartz powder, potash, red lead) w/scoops or spoons next to them; scale with beaker on it, glass tray with wet paper towel on top to prevent copper sheet (goes on top of this wet paper towel) from sliding around while grinding, copper sheet and muller

EXPERIMENT (all under fume hood)
1) measure out 1 dram (3.54g) quartz powder in beaker and transfer onto copper sheet; GENTLY place muller on top and grind thoroughly (‘figure 8’), paying close attn. that powder does not go beyond copper surface (the quartz powder is very fine and very light—the wind in the fume hood as well placing the muddler on top of the powder too quickly/aggressively can easily force some of the powder off the copper sheet). There should be a sound of grinding, the copper sheet should look like it is getting “polished” in area where there is grinding, and powder may change color (the graying in experiment 1 could be due to the powder collecting bits of copper but could also be due to oil residue on muller)

prepare to work with red lead next: dust mask, goggles, remove jewelry on hands and wear two pairs of gloves, tape lab coat/glove area so no lead will get on skin of clothing. Make sure fume hood is below breathing level

2) carefully measure out 10.6g of lead into beaker (lead is heavier than the quartz powder so add in small amounts to reach 10.6g). Recommended to do this with a plastic spoon that can be thrown in hazmat container
3) carefully transfer red lead to ground quartz powder on the copper sheet—you want to do this in a manner that reduces likelihood of lead particles flying around; angle the beaker in such a way that the lip touches the copper sheet and the lead can slowly/smoothly pour onto the sheet based on the angle at which you are holding the beaker. Lightly tap the bottom of the beaker with lip still touching copper sheet to get all the red lead out
4) use palette knives to combine the two ingredients into a mixture and then grind with muller; The red lead will be heavier and thicker to grind, almost like a paste. Use palette knives repeatedly to pull the outer edges of the ground mixture back towards the center of the copper sheet and continue thoroughly grinding, making efforts to keep all of the powder mixture onto the copper sheet. As you grind, the color of this mixture may also darken slightly. Pull the quartz/lead mixture together and form a little area/pool in the center into which you can add the potash and prevent it from rolling off.
5) measure 1 dram (3.54g) of potash in the beaker and add to mixture on copper plate. these are small beads that can easily roll off the copper sheet. Gently crush the potash with the muller by simply placing it on top of the potash and pressing downward to crush the pieces. Grind/mix the potash/quartz/red lead mixture.
6) place the mixture into the crucible and cover with lid.
7) remove all containers and objects not exposed to lead and prepare to clear out the space for THOROUGH cleaning.

CLEAN UP/PREPARATION FOR HEATING
all tools that have been in contact with red lead (palette knives, muller, beaker, copper sheet, glass plate, etc) MUST be cleaned in oil with the paper towels used to clean them tossed into the hazardous waste container (all under the fume hood).
-Tools, once thoroughly cleaned with oil, can be washed with soap and water but NOT by those who have been working with the lead.
-Newspapers and wet paper towels lining the ground of the fume hood must CAREFULLY be bundled up in such a manner that any and all red lead that has been blown beyond the working area (of the copper sheet) is collected. Collect all of this and throw in hazardous waste container
-tape must be removed from wrists/lab coats (preferably by someone else wearing gloves) and then removed carefully—invert one of the gloves, then either use that inner part of the used/removed glove (which is now facing out) and use that to take off the other glove OR slide bare hand carefully under remaining glove to invert that and toss immediately into hazardous waste container.
-Wash hands, wrists, upper arms thoroughly with soap and water.

PREPARE for heating (Joel created the furnace we used in experiment #1…we should speak to him about what he did and how)
1) set up furnace and place crucible inside it (question of “luting” the crucible?)
2) heat (question of how high and for how long)
3) remove the lid of the crucible when contents are molten
4) remove heat while keeping crucible uncovered and inside the furnace, allowing it to cool at a very slow pace
5) remove contents from crucible (by breaking it? Chisel?)


BnF Ms Fr 640 p100v (FRENCH)
<page>100v</page>
<image>http://gallica.bnf.fr/ark:/12148/btv1b10500001g/f206.image</image>

<div>
<id>p100v_1</id>
<head>Pierrerie</head>

<ab>Prens des <m>caillous</m> blancs qui se trouvent par<lb/>
les rivieres & parmy le sablon & les chemins, qui sont<lb/>
aulcunnement transparents, & s’ils le sont parfaictemment ce<lb/>
sera mieulx. Sinon use des meilleurs & plus blancs<lb/>
que tu pourras. Calcines les trois ou 4 fois<lb/>
dans ton four à vent & les estaints dans de l’<m>eau</m><lb/>
ou <m>vinaigre</m>. Après prens en une <figure>℥</figure> et les pile<lb/>
dans un mortier tout pur de <m>cuivre</m> & avecq un pilon<lb/>
de pur <m>cuivre</m>, et les broye jusques à ce qu’ils<lb/>
soient en pouldre fort subtile & doulce, et cela est<lb/>
un signe qu’ils ont prins de la substance du <m>cuivre</m><lb/>
asses pour leur donner verdeur. Lors sur ton <figure>℥</figure><lb/>
de <m>caillou</m>, mects y trois <figure>℥</figure> de bon <m>minium</m> non sophistiqué<lb/>
de <m>brique</m> & d’aultre chose. Et broye encores bien<lb/>
fort tout ensemble dans le mortier de bronze.<lb/>
Et sur tout cela, mets y un gros <add><del>pour <figure>℥</figure></del></add> de <m>sel de verre</m><lb/>
& aulcuns & le commun y mect d<del>e</del>u suinde <m>verre</m><lb/>
qu’ils trouvent ches les <pro>verriers</pro> ou <pro>apotiquaires</pro>.<lb/>
Mays le <m>sel alchali</m>, comme tu sçais, est meilleur.<lb/>
En cest sorte le vulgaire faict des <m>esmerauldes</m><lb/>
& en gectent en <m>sable</m>. Si tu n’as point de <m>mortier</m><lb/>
de bronze, broye <del>un mort</del> dans un chauldron<lb/>
de pur <m>cuivre</m>.</ab>

<note>
<margin>left-top</margin>
Il fault faire<lb/>
recuire plustost<lb/>
les creusets qu’i<lb/>
mectre les matieres<lb/>
et les mectre dans<lb/>
la fornaise ou<lb/>
four à vent plustost<lb/>
que faire & augmenter<lb/>
le foeu.

<figure>A “four à vent” containing a crucible</figure>
</note>

<note>
<margin>left-center</margin>
Elles sont faictes<lb/>
en une heure & demy.
</note>

<note>
<margin>left-center</margin>
Un gros de <m>sel</m><lb/>
sur les quattre <figure>℥</figure><lb/>
de <m>caillou</m> & <m>minium</m>.<lb/>
Quand on dict pour <figure>℥</figure><lb/>
cela s’entend sur une<lb/>
<figure>℥</figure> du corps & non pas<lb/>
des <m>sels</m> & du <m>minium</m>
</note>
</div>

<div>
<id>p100v_3</id>
<margin>left-center</margin>
<head><m>Esmeraulde</m></head>
</div>

<div>
<id>p100v_2</id>
<head>Pour <m>ruby</m> prens de l’<m>or</m><lb/>en foeille</head>
<ab>Haulsse ton four de deulx tuiles tout aultour pource qu’il<lb/>
fault plus de chaleur pour fayre <m>rubis</m> que pour <m>esmerauldes</m><lb/>
Et prens une <figure>℥</figure> de <m>caillou</m> blanc calciné, et la mects dans<lb/>
un mortier de verre & l’ayant grossierement broyé<lb/>
avecq le pilon de mesme. Mesles y <del>un grain</del> le poix d’un<lb/>
grain d’<m>or</m> en foeille de quoy les painctres dorent & broye

<note>
<margin>left-bottom</margin>
Aulcuns disent que<lb/>
meslant l’<m>or</m> avecq<lb/>
les <m>caillous</m><lb/>
et le <m>salpestre</m> il<lb/>
faict couleur de<lb/>
peschier.</note>

<note>
<margin>left-bottom</margin>
Aulcuns disent qu’il<lb/>
fault que l’<m>or</m> soict<lb/>
plusieurs foyes <m>cimenté</m><lb/>
puys battu en foeille</note>
</div>



BnF Ms Fr 640, p100v (ENGLISH)

<head><m>Gemstones</m></head>

<ab>Take some white <m>stones</m> that are found along rivers, in fine sand, and paths, and that are somewhat transparent. If they are perfectly transparent, it will work better. If not, use the best and whitest ones that you can. Calcine them three or 4 times in your “four à vent” and quench them in <m>water</m> or <m>vinegar</m>. Afterward, take a <figure>℥</figure> of them and crush them with a mortar and pestle, both of pure <m>copper</m>, and grind them until they become very fine powder, which is a sign that they [the stones, now finely ground] have taken on enough of the <m>copper</m> to give them a green quality. Then in your <figure>℥</figure> of stones, add in three <figure>℥</figure> of good <m>minium</m>, unadulterated by <m>brick</m> or something else, and strongly grind everything together again in a <m>bronze</m> mortar. And in all of this, add in a “gros” of <m>glass salt</m>, and some and the common people add in <m>sandever</m> that they get from <pro>glassmakers</pro> or <pro>apothecaries</pro>. But <m>alkali salt</m>, as you know, is better. In this way, the vulgar make <m>emeralds</m> by casting them in sand. If you do not have a <m>bronze</m> mortar, grind in a cauldron of pure <m>copper</m>.</ab>

<note>
<margin>left-top</margin>
One must heat the crucibles before putting anything in them, and must put them in the forge or “four à vent” before making and building up a fire.

<figure>A “four à vent” containing a crucible</figure>
</note>

<note>
<margin>left-center</margin>
They are done in an hour and a half.
</note>

<note>
<margin>left-center</margin>

A “gros” of <m>salt</m> in four <figure>℥</figure> of <m>stones</m> and <m>minium</m>. When they say for <figure>℥</figure>, that is to be understood as a <figure>℥</figure> of body and not <head><m>esmeraulde</m></head> the of <m>salts</m> and of the <m>minium</m>.
</note>
</div>

<div>
<id>p100v_3</id>
<margin>left-center</margin>
<head><m>Esmeraulde</m></head>
</div>

<div>
<id>p100v_2</id>
<head>For <m>ruby</m> take some <m>gold</m> leaf</head>
<ab>Raise your stove by two tiles on each side because more heat is needed to make <m>rubies</m> than is needed for <m>emeralds</m>. And take a <figure>℥</figure> of white, calcined <m>stones</m>, and put it in a <m>glass</m> mortar and, having vigorously ground with a <m>glass</m> pestle, mix in the weight of a grain of <m>gold</m> leaf used by painters for gilding, and grind

<note>
<margin>left-bottom</margin>
Some say that mixing the <m>gold</m> with <m>stones</m> and <m>saltpeter</m> makes the color of a peach tree.</note>

<note>
<margin>left-bottom</margin>
Some say that the <m>gold</m> has to be cemented several times and then beat into sheets.</note>
</div>


Our preliminary edited version of recipe [English]:

Take some white stones that are found along rivers, in fine sand, and paths, and that are somewhat transparent. If they are perfectly transparent, it will work better. If not, use the best and whitest ones that you can. Calcine them three or 4 times in your “four à vent” and quench them in water or vinegar. Afterward, take a ℥ of them and crush them with a mortar and pestle, both of pure copper, and grind them until they become very fine powder, which is a sign that they [the stones, now finely ground] have taken on enough of the copperto give them a green quality. Then in your ℥ of stones, add in three ℥ of good minium, unadulterated by brick or something else, and strongly grind everything together again in a bronze mortar. And in all of this, add in a “gros” of glass salt, and some and the commun add in sandever that they get from glassmakers or apothecaries. But alkali salt, as you know, is better. In this way, the vulgar make emeralds by casting them in sand. If you do not have a bronze mortar, grind in a cauldron of pure copper


One must heat the crucibles before putting anything in them, and must put them in the forge or “four à vent” before making and building up a fire.


A “four à vent” containing a crucible


<margin>left-center</margin>
They are done in an hour and a half.


<note>
A “gros” of salt in four ℥ of stones and minium. When they say for ℥, that is to be understood as a ℥ of body and not esmeraulde the of salts and of the minium.


For ruby take some gold leaf
Raise your stove by two tiles on each side because more heat is needed to make rubies than is needed for emeralds. And take a ℥ of white, calcined stones, and put it in a glass mortar and, having vigorously ground with a glass pestle, mix in the weight of a grain of gold leaf used by painters for gilding, and grind


<note>
Some say that mixing the gold with stones and saltpeter makes the color of a peach tree.


<note>
Some say that the gold has to be cemented several times and then beat into sheets.


Another related recipe in Bnf Ms Fr640:
p101v
<page>101v</page>
<image>http://gallica.bnf.fr/ark:/12148/btv1b10500001g/f208.image</image>


the crucible is red. Then throw it on a marble, and you will obtain a white, hard and uniform matter, similar to <m>alabaster</m>, from which you will be able to cast medals which will look like marble; but keep them away from humidity.</ab>
</div>
<div>
<id>p101v_1</id>
<head><m>Hyacinth</m></head>


<ab>It is made, like <m>rubies</m>, with <m>gold</m>; but without such intense heat. <m>Rubies</m> need to be heated for a whole day, and if it does not have heat for long enough, you will obtain only reddened varnish.</ab>


<note>
<margin>left-top</margin>
Always heat up your crucibles.
</note>


<note>
<margin>left-top</margin>
It is believed that rubified <m>antimony</m> makes <m>hyacinth</m>.
</note>
</div>




Mrs. Merriefield alternative from Bolognese Manuscript, 15th century (pp. 508-9)
238. To make stone for rings, that is to say precious gems clear and of a fine colour. And you may, in this way, quickly and easily, make pearls, rubies and balas rubies, which are artificial, and not natural. Take of the good stone which is called alabster of Constantinople (footnote 1: the Alabaster appears to supply the place of the pounded bricks used in the common process of distilling oil. The object of employing it was to equalize the heat and to economize time and fuel. It probably also prevented the danger of the oil boiling over.) as much as you like; first make it hot like iron and quench it in very strong white vinegar; afterwards grind it fine in a bronze mortar, and put the whole of it into linseed or olive oil, and let it remain for 3 days or more. Afterwards put it into a cucurbit, and distill it through an alembic, and collect and keep what comes over. And when you wish to colour it, put into that water whatever colour you like, and it will keep its colour for ever. So if you want to have a sapphire, put ultramarine azure into it. If you wish to have an emerald, put in some verdigris. If you wish to have a topaz, put in some oil from the yolks of hen's eggs and tin, and a certain water must be made by soaking the colour in it for three days with some alum zucarino or scagliola, and then strain this coloured water through a fine and close linen cloth, and in the same manner do what you please. Then thicken it by the fire to the consistence of dough, and take some of that paste and cut it into whatever shape you like, a stone or a cup, or a vase, boiling it well with olive or linseed oil, or with oil of bitter almonds; dry it in a hot sun upon a polished board, and it will be like true and natural stone, and preserve this recipe as of great use and advantage. (p. 506)

239. You may make in the following manner with crystal, painted and factitious stones, such as topazes, sapphires,
FILL IN (P. 506)


242. To make rubies: Take of roche alum 2, 1, of saltpetre 3, 1, and reduce them to fine powder together; then take verzino boiled with wine till reduced one half, and with this wine mix and knead up the said powders to the consistence of sauce; put them into a glass vase with a gentle fire, that the liquid may evaporate, and that the whole may form one mass. Take it off the fire, and let it stand 7 days, and you will find a well-coloured substance like dough, mould it into any shape you please.


243. To make balas rubies: Put a stone of pure crystal into a hollow iron ladle, and make a good fire under it. When the whole of the ladle, with the stones in it, is red hot, take clear and cold spring water, and throw a drop of it upon the stone, and afterwards put it back gently to the fire; then take dragon’s blood in fine powder, make it into a lump, and anoint the stone, and put it back to the fire so that the ladle may get red hot with a little fire, and then remove it from the fire and let it cool near the fire, and when it is almost cool, rub it with a piece of very rough woollen cloth, and it will be well done.


268. To make red glass: Take 1 lb. of copper, and melt it, (p. 524) and when it is melted add 4 oz/ of lead, and incorporate them well with each other and throw the mass into cold water, and it will be broken small like grains of corn. Then grind it as fine as you can, and stir it into the glass, and it will become red glass, for making paternosters and other articles. Also note that copper filings thrown into the glass make a red, but they require a very gentle fire. Calcined lead has the same effect, and so also has minimum and white lead. (p. 526)
[related comparative recipe re: significance of copper for red coloring]

271. To make blood red glass: Take 100 lbs. of white glass and melt it in the furnace, and then take 8 lbs. of calcined maganese pounded, and 8 lbs. of sal alkali, which is to be mixed with the manganese, put these ingredients into a jar in the furnace to remain white hot for one day, and mix them well with an iron rod, and then take the mass out and reduce it to powder. Next take 3 lbs. of this powder and put it with the glass, that is to say, with 10 lbs. of glass; stir it well with the iron and let it fine itself. If it is too dark, add white glass to it; and if too light, add more of the material to it, and it will be good and perfect. (p. 528)
[related comparative recipe re: red glass variants]


green: unclear term
yellow: unclear process
orange: difference of material b/t BnF and Merrifield

Cellini discusses rubies in chapters IV (Jewellery), V (How to set a ruby), and XI (About white rubies and carbuncles)
-discusses not only various kinds of rubies but also the price of rubies compared to sapphires, emeralds, and diamonds (Kessinger Publishing, p. 23)
-discusses "dunderheads" re: discerning qualities of the stones (Kessinger Publishing, p. 22)
may be good also to look at chapter VII (How to make foils for all sorts of transparent jewels)






BnF Ms Fr 640 p100v RECONSTRUCTION OF IMITATION GEMSTONES

Friday, Oct 16, 2015

making and knowing lab, chandler hall


Date: 16.10.2015
Time: 9:05am



1.5+ hrs spent as a group deciphering problems in the manuscript and its translation. These mostly revolved around understanding a "dram" and "un gros (de sel)". Re: dram, we were not sure if this was meant to equal 3.54g or 1.77g as per Avoirdupois system. We settled on 3.54g after consulting other sources, namely Middle French dictionaries.



8 drams made 1 oz = 8 drams = 28, 34 grams - Cotgrave:

https://books.google.com/books?id=ISi4M196tl4C&pg=PT221&lpg=PT221&dq=cotgrave+dram&source=bl&ots=AEqZMFf_sx&sig=FJjgDLl1ELXqeY7yYmAueloCd2I&hl=en&sa=X&ved=0CDYQ6AEwBGoVChMItej73prHyAIVBqkeCh3cBwOj#v=onepage&q=cotgrave%20dram&f=false



Next was the issue of "un gros de sel" written in a marginal note, and how exactly to translate "un gros de". A pinch? A piece? Coarse salt? "Gros sel" appears multiple times in the manuscript but "gros de sel" does not.



We decided on 3 trials with varying additions of alkali salt



1 1:3:1 (quartz powder:red lead:alkali salt)

2 1:3:1/2

3 1:3:2



10:45am

preparing to begin



We are using:

3.5g Kremer 58620 Quartz Powder (in tub, not coarse one in plastic bag)

10.6g Kremer xxxxx Red Lead (in tub, wrapped in plastic)

3.5g Kremer xxxxx Potash (potassium carbonate, in tub)

BEWARE: red lead is incompatible with aluminium, it can form an explosive compound.

A reminder to always look (and re-look) at safety data sheets!

SET UP in FUMEHOOD:

To prepare for the process of mixing, I first thoroughly wiped down the entire surface/ground of the fume hood with wet paper towels, then wiped it down again with a dry paper towel. We then spread out newspapers across the entire surface, several layers thick (as many sheets as could comfortably slide under the vertical poles at the rear of the fume hood--approx. 2-3 sheets). Next we spread out damp paper towels, particularly in areas where there would be lead. A glass plate was set on top off the wet paper towels and then topped with a wet paper towel to prevent the copper sheet on top of it from sliding around. All the ingredients were placed on the left side of the fume hood interior--in their plastic tubs. Two stainless steel "scoopers" and one plastic spoon (for red lead), the scale with a beaker on top of it (set to weigh in grams).

Trial #1

I measured out 1 dram (3.5g) of the quartz powder into the beaker. I replaced the lid onto the tub of quartz powder and placed the scoop I had used next to it to make sure I only used it with that one substance. I transferred the powder onto the copper sheet by gently pouring it out--tipping the beaker with its lip touching the sheet and slowly raising the bottom of the beaker up, gently tapping the back to get all of the powder out. I consolidated the powder using two small palette knives. I reached for the muller and placed it on top of the powder to begin grinding and was surprised at how much seemed to blow away because of the way I placed the muller down. I did not force it or move too quickly, but I needed to be even more gentle--the powder is extremely fine. I reconsolidated what had blown away, pulling it forward with the palette knife, and very gently set the muller down on top of it a second time. I did not see any of the powder fly away this time.

Grinding was quite challenging to start--I was worried about the powder blowing away and also aware of how much powder was on such a small copper sheet. I would have felt more comfortable if we had had a larger copper sheet, but given the small size of it, it seemed like a lot of the powder could easily be pushed off the sheet and end up on a wet paper towel. I grinded with a lot of force, beginning in a small area and making a 'figure eight' shape as recommended by Marjolijn. Within a few minutes--maybe 2--the process was much easier. It is hard to say whether I simply became familiar with the material I was working with, with the movements, or if it was getting easier because it was being ground down. There was definitely a sound to the grinding, but to hear the sound it required a lot of pausing to reconsolidate the powder and begin grinding a different portion of the amount on the sheet. within 5 minutes, I noticed a color change in the powder; it had gone on the sheet and looked quite white, but as I would scrape bits of it back together with the palette knife, I noticed very clear distinctions between a white powder and a light gray powder. The more I ground, the more the powder turned gray. We also remarked on how much of the color of the copper sheet had changed. While grinding, we were simultaneously polishing the copper, making it seem like the powder must have been absorbing tiny bits of the copper which, we had suspected, would assist in turning the finished "gemstone" green. Marjolijn also suggested that it might be turning gray due to residual oil still on the muller. It would be good to make sure the muller is as clean, oil-free, and dry as possible.



We (Jenny, Marjolijn and I) took turns grinding the powder to get a feel for it. We felt it had been thoroughly ground when all of the powder had turned dark gray--I had taken my watch off but would estimate 10 minutes. Then, before incorporating the red lead, we followed safety instructions to prepare for working with it. Dust masks, goggles, and double layers of gloves, tapped around the wrists (this was not done so properly to start but I was retaped by Pamela shortly after). The safety person who was present asked if we could begin with a smaller dose of lead than was called for, as an addtional safety precaution because he said there might be some kind of reaction. We agreed to start with one dram (instead of three) to see if anything would happen. I lowered the fume hood slightly for extra precaution and opened the jar of red lead. With the plastic spoon, I began putting the red lead into the beaker. I was immediately struck by how much heavier the lead was than the quartz powder. I did not feel this in my hand because the spoon only had a small amount...but the scale was showing an increasing weight so much more quickly than it was with the quartz. There was a drastic difference in the weight of the two. 1 dram (3.5g ) was measured out. I closed the lid of the red lead jar and placed the spoon next to it. I gently put the red lead onto the quartz powder and combined the two with two palette knives. I began grinding it. It was very difficult to grind. It was hard for the muller to even move--it felt so sticky or gummy. I mentioned this to Pamela who was standing next to me and she said that the author of the manuscript uses words like fatty or greasy to describe lead. It not only looked like the color of cheetos cheese powder, but it felt like how I'd imagine grinding that would be...it's a powder but it's greasy and sticky. When you get the powder on your hands you can't really rub it off. It spreads like grease. So "grinding" this mixture didn't feel like grinding. There was little sound of grinding as compared to the quartz powder. But we continued. marjolijn and I were the only ones properly dressed/protected to do it, so we took a few turns and then she handed it off to me as she wanted to take photos. This continued and got slightly easier as time went by. I kept grinding and noticed a difference in color--the brightness of the red lead had gotten duller, grayer, as well. The grinding lasted approx 10 minutes.



When it was time to add the potash there was some discussion about whether it was necessary or not to grind it. Pamela and Marjolijn suggested that it wasn't really necessary. The manuscript says to add the alkali salt to a bronze cauldron and then grind. It seems that those with more experience in science or in glassmaking felt it didn't really matter whether it was ground or not. Pamela asked me what I wanted to do and I said I'd like to grind it...or at least crush the potash as they were in little balls. I definitely trusted that they knew what they were talking about (that it's not really necessary to grind) but I thought, since it says to do so in the manuscript, I might as well try to stay as close to it as possible.



I measured out 1 dram of potassium carbonate into the beaker, closed the jar and put its scooper next to it. I swirled the beaker around only briefly, maybe one or two swirls, and it was amazing how it began to turn orange. I had noticed a very tiny amount of red lead left inside the beaker from when I had measured it out (another sign of how "sticky" it is). These few little swishes of the potash seemed to scrub the red lead residue off very well AND take on the color...and from such a miniscule amount of lead. I poured the potash out onto the lead/quartz mixture in 2 doses because there were a lot of these litle balls and I didn't want them to roll off the copper sheet. I simply pressed the muller down on top of each bundle of potash balls and pressed down firmly, just moving my wrist in different directions to break the balls thoroughly under the base of the muller. There was quite a sound--little pops, explosions. It reminded me of both the sound and the sensation of eating pop rocks. Tiny little bursts, quite pleasurable to feel these things crackling under the muller. Once they were popped, I very lightly ground them in with the quartz/lead mixture. I probably would have done this slightly longer than I did but, as others had said it really wasn't necessary to grind the potash, I figured it was equally not so important to get the particles all well blended together.

I consolidated all of the powder/mixture with palette knives. Marjolijn handed me a winder palette knife thing with a rounded tip (sort of like a small spatula) and I used this to transfer the mixture into the crucible. All of the mixture easily fit into the crucible.

It's bright orange. We transferred the mixed powder into a crucible. Then clean up began in order to clear the fume hood for heating up the crucible.



all of the materials that had not had contact with the lead were removed--the jars of quartz powder and potash, their scoopers, etc. Marjolijn and I were the only ones in the protective gear to work with the lead so we worked on cleaning all of this under the fume hood. Everything that had been in contact with lead was cleaned with linseed oil. We cleaned the muller as you would an oil paint brush--she gave me paper towels with little puddles of oil, and I rubbed all over the muller's flat part as well as the body of it in oil. I then rubbed the flat portion on clean paper towels until there was absolutely no red lead smearing across the towel. We thoroughly cleaned the palette knives, etc in a similar way, and these were then washed with soap and water. We gently collected all of the newspapers and wet paper towels that were under the fume hood. It was amazing to see just how far some of the red lead had spread. Its color is so striking, it's quite easy to see small particles against newspaper print. We had to slowly bundle everything up, making efforts to do so carefully so that particles would not drift off the newspaper and onto the surface of the fume hood. When all was properly removed from the fume hood, we removed our gloves and put them in the hazardous waste container, then thoroughly washed our hands, wrists, and upper arms.



Joel then began setting up for the 2nd part of the experiment: heating the crucible.

He used a self-built furnace and I need to talk to him about exactly how he set it up.



There was discussion of whether or not heat the crucible with or without the lid. We referred to the drawing of the furnace on the manuscript page. It looks a bit like underpants (at first...to someone like me who hasn't seen furnace illustrations before) but it also sort of looks like the contraption Joel has set up in the fume hood. The recipe in the manuscript says nothing about placing the lid on it or not so we look at

Self built furnace from Joel set up in fume hood, fire torch

see drawing on fol. 101v

we put the covered crucible into the furnace.

we rehearsed what to do in case of emergency, explosion: try first to get torch out of fume hood. close slash of fume hood. leave lab

we started as low a flame as possible with our torch in order to not break the crucible.

Time

12.12 we started to heat the crucible after 1 minute still at room temperature

12:13 Joel turns heat up on torch

12:14 temperature of the lid raises over 200 celsius

12:17 over 300 celsius

12:18 over 400 celsius

12:23 above 500 celsius our thermometer cannot measure higher temperatures

12:30 Joel thinks we now reached about 1500 celsius

12:33 joel lifted the lid. its def smolten and fluid, bright red. he can pour it

Joel said about 10 minutes of good heating

We need to go up to about 1500 celsius to reach the melting point of quartz to which alkali salt is added

J: interesting exeperience when pouring it, it's heavy

we observed amazing color changes: bright red in crucible, dark red when poured out, on surface it turned darkish greyish green and it "froze" while pouring. We poured it into a silicon mold and this is where it started to start changing colors very quickly (burned the mold). It was cooling so quickly that a "string" of the liquid started solidifying while it was being poured, forming a thin, slightly undulating needle of glass. It was so hot that it started burning the mold and so we quickly removed it. When we lifted the "glass stone" (with its tail/needle) and rested it on the furnace stone it turned darker and darker and then broke open, showing that it was sort of a very fragile glass bell. it took the impression of our mould very well. Pamela noticed a bubble at the surface and this was the first piece to shatter.

it turned darkish blackish green, but the thin glass fiber remained transparent with traces of greenish. when cooling the impression still seemed to change color. turning a little bit lighter green again and slightly goldish.

we might have heated it too much as pamela recalls that if it is heated too much it turns black.

The color seemed to change slightly for several minutes, even while the glass was cool enough to touch.

12:54--inspecting the crucible and it is markedly more green inside than the black stone. As it is pulled out, within moments (less than a minute) the color starts changing. It becomes less green and more black, and then it starts cracking. This seems to be related to how quickly it is cooled. The crucible was kept in the heat chamber and allowed to cool organically, therefore this could be related to why it stayed a greener color than our black glass/stone.



-need to go up to 1100/1200 celsius (to melt copper)


Questions:

1. was it heated to high?
2. will it require gold to turn red?
3. color of ruby to green briefly to black--was it cooled too quickly? (remove crucible lid when stuff inside is molten)

---

RED VARNISH

BnF Ms Fr640 p078r

Ingredients needed:

• Spike lavender oil
• sandarac
• vermillion
• gum water

Instruments needed:

• coals (to heat spike lavender oil)
• glass vial

TC:


<div>
<id>p078r_1</id>
<head>Aultre vernis</head>
<ab>Prenes une once <m>dhuile daspic</m> & la fais chaufer sur les<lb/>
charbons & puys prenes demy once de <m>sang dea Ratc</m>[illeg]<lb/>
& la broye grossemen[illeg]t et puis le mectz dedans <m>lhuille daspic</m> &<lb/>
puys le mesle aveq ung baston tant q{ue} voyrres q{ui}l sera<lb/>
fondu et puys le mectz dedans une fiolle de verre Et<lb/>
quand tu en vouldras user faut le chauffer peu a peu sur<lb/>
Les charbons Et devant q{ue} Le poser, pose une couche de<lb/>
<m>colle</m> bien clere, & puys le pose aveq Le pinceau</ab>
</div>


<div>
<id>p078r_2</id>
<head>Pour faire verny Rouge</head>
<ab>Prenes du <m>vermilhon</m> & le fais tremper aveq de <m>leau de<lb/>
gomme</m> ainsy q{ue } dau{ltr}e <m>eau</m> et en fair comme dud{ict} verny<lb/>
& mesle ceste au{ltr}e <m>eau</m> comme dau{ltr}e verny et puys le<lb/>
couche comme devant pour faire bois verd</ab>
</div>



TCN:


<div>
<id>p078r_1</id>
<head>Aultre vernis</head>
<ab>Prenés une once <m>d’huile d’aspic</m> & la fais chaufer sur les<lb/>
charbons, & puys prenés demy once de <m>san<corr>darac</corr></m><lb/>
& la broye grossement et puis le mectz dedans <m>l’huille d’aspic</m> &<lb/>
puys le mesle aveq ung baston tant q{ue} voyrres q{u’i}l sera<lb/>
fondu, et puys le mectz dedans une fiolle de verre, et<lb/>
quand tu en vouldras user faut le chauffer peu à peu sur<lb/>
les charbons, et devant q{ue} le poser, pose une couche de<lb/>
<m>colle</m> bien clere, & puys le pose aveq le pinceau.</ab>
</div>


<div>
<id>p078r_2</id>
<head>Pour faire verny rouge</head>
<ab>Prenés du <m>vermilhon</m> & le fais tremper aveq de <m>l’eau de<lb/>
gomme</m> ainsy q{ue } d’au{ltr}e <m>eau</m> et en fais comme dud{ict} verny,<lb/>
& mesle ceste au{ltr}e <m>eau</m> comme d’au{ltr}e verny et puys le<lb/>
couche comme devant.</ab>
</div>

TL:

<id>p078r_1</id>
<head>Another varnish</head>
<ab>Take one ounce of <m>spike lavender oil</m> and heat it over coals; take a half ounce of <m>sandarac</m> and grind it coarsely , and then put it in the <m>spike lavender oil</m> and mix it with a stick until it has melted, and then put it in a glass vial, and when you want to use it you must heat it little by little over the coals, and before applying, lay a coat of very clear <m>glue</m>, and then apply it with a paintbrush.</ab>
</div>


<div>
<id>p078r_2</id>
<head>To make red varnish</head>
<ab>Take <m>vermillion</m> and dilute it with <m>gum water</m> as well as with other <m>water</m> and make it like said varnish, and mix this other <m>water</m> the same way as other varnish and then apply it as above.</ab>

Our rewriting of the recipe:

Another Varnish:
Heat [temperature? duration?] a glass beaker of one ounce of spike lavender oil [oil of spike] [on a hot plate].
Take a half ounce of sandarac and grind it coarsely.
Put the ground sandarac in the spike lavender oil and mix until fully dissolved.
Heat the mixture slightly before applying.
Lay a coat of size [?] on painting surface before applying with a brush.

To make red varnish:
Dilute [a half ounce of? improvising from above] vermillion with gum water [?] as well as [tap or distilled?] water.
Add mixture to one ounce of spike lavender oil and heat [temperature? duration?] in a glass beaker [on a hot plate].
Heat the mixture slightly before applying.
Lay a coat of size [?] on painting surface before applying with a brush.


"Oil of spike" = Oil distilled from Lavandula spica, used as a diluent for varnish. Its properties are similar to those of turpentine (q.v.) [Merrifield, xxv]

"Sandrac" = yellowish resinous body obtained from the stems of the conifer Callitris quadrivalvis, used in the preparation of varnish. Syn.: Gomma di genitor, Vernix [Merrifield, xxix]


"gum water" = [Merrifield lists only "gum ammoniac," "gum arabic," "gum deer," "gum lac," "gum tragacanth," and "water of tartar" - none of which address varnish preparations]
*GUM WATER RECIPE IN BOLOGNESE MANUSCRIPT (Merrifield)
229. To make gum water. -Take clear water in a glass cup with gum arabic in powder and make it rather warm over the fire until it is well liquefied, and then keep it in a phial and use it. (p. 502)
*GUM WATER RECIPE IN PADUAN MANUSCRIPT (Merrifield)
14. How gum water for dissolving and distempering the colors for miniature painting is made (p. 658)

Other recipes related to varnish in Bnf Ms Fr640:

p071v
<div>

<id>p071v_1</id> <head>Varnish</head>
<ab>Add 4 <figure></figure> of <m>sandarac</m> and finely pulverized <m>mastic</m> to a half lb of <m>aspic oil</m>. First of all, boil your <m>oil</m> in a pot on a stove, and then add the aforesaid <m>gum</m> little by little, stirring continually with a small stick split and quartered at the end. And when you cannot collect any more <m>gum</m> on the end, it is totally melted and your varnish is done. And to make it clearer, put into the concoction a little lump of <m>camphor</m>. It is true that with this it will not dry as quickly. Heed well that the <m>aspic oil</m> is quite clear and not at all fatty, otherwise your varnish will not be worth anything. You can test it by soaking some <m>paper</m> in it and heating it. If the <m>oil</m>, which will evaporate, leaves the
<m>paper</m> clean, without a yellow mark, it is good, if not, it is fatty.</ab> </div>

<div>

p074r

<id>p074r_3</id>

<head>To make varnish</head>
<ab>Take one pound of <m>linseed oil</m>, and then put it in a pot of <m>earth</m> mixed with a <m>bread</m>crust and three <m>onions</m>, and put it on a <m>charcoal</m> fire, and you will cook it on a low fire, and let it boil for the space of five hours. You will take half an ounce of <m>flour glue</m>, and will make it boil just as before, and with a spoon. And then afterwards, you will add two ounces of well-pounded <m>sandarac</m> to it, and will do so as above. And then afterwards, you will take <m>mastic</m> and <m>^gumarabic</m>, two ounces of each, both well pounded, and will put everything together, and will have it boil, always

stirring, for the space of five hours. And then you will add <m> m</m>, two ounces, and then you will make it boil. And if you add two ounces of <m>^gumarabic</m> to it, if you see that they are not enough, have it cook more on a low
<page>074v</page> <image>http://gallica.bnf.fr/ark:/12148/btv1b10500001g/f154.image</image>
<id>p074r_3</id>

fire until it is cooked enough. And strain it through a cloth that is enough. And when you have strained it, leave it to cool a little. And if you see that it is so thick that you cannot strain it, you will add a little of that oil and will make it better.

</ab>

</div>
<div>

p074v

<id>p074v_1</id>

<head>To make red varnish</head>
<ab>Take <m>vermillion</m>, and let it soak in <m>gum water</m>, like the other, and make two or three ground layers as is said above.

</ab>

</div>

p097v

<page>097v</page>
<image>__http://gallica.bnf.fr/ark:/12148/btv1b10500001g/f200.item__</image>


<div>
<id>p097v_1</id>
<head><m>Mastic</m> varnish dried a half hour</head>


<ab>
Some use 2 <figure>℥</figure> of <m>mastic</m>, half <figure>℥</figure> of <m>turpentine</m> and of <m>turpentine oil</m>, and <m>spirits</m> at your discretion since it evaporates when heated and nonetheless makes a more desiccative varnish. But I made it like this: I use <m>turpentine oil</m>, at my discretion, and add very little <m>turpentine</m>, since it remains humid and gets tacky if we add too much, together with some <m>spirits</m> and heat the <m>oil</m> in a varnished bowl and, as it become very hot I add some finely ground <m>mastic</m> and pass one-third of the <m>oil</m> through a sieve and let this heat up until it is melted, which will occur quickly on hot <m>ashes</m>. Once it is all melted, try it on your knife, and if you see that it has too much body add a bit of <m>turpentine oil</m>, and if it does not, add some <m>mastic</m>. And so it is finished, and keep it well covered so that no rubbish gets in. When you want to make this, take care to separate and choose the <m>mastic</m> that is white and pure of any dirt and dust and black dross. And when you wash it and dry it, make it very white and clean and make it even better, because if you don’t purge it of these dregs and marks they will be pulverised into it, remain within the varnish, and when you wipe it onto some white or flesh-tinted ^surface, it will seem as if it were spotted and dirty. Having properly selected, pulverise it in a mortar and pass it through a very fine sieve, and afterward mix it in <m>oil</m>, as stated above. But if you want to make it more carefully, take a drop of <m>mastic</m>, as you know, pulverise, pass it, and mix, and you shall have something very singular for small projects. Be well advised when varnishing to not breathe on it for it will make the varnish white and thick.</ab>


<note>
<margin>left-top</margin>
It almost dries as you are working on it.</note>


<note>
<margin>left</margin>
We know that this varnish does not have enough body when it doesn’t take well to an <m>oil</m> painting, since it is like <m>water</m>. Add, therefore, powdered <m>mastic</m> and heat it until it is good. This varnish is very white and beautiful not at all like the <m>aspic</m> one.</note>


<note>
<margin>left-middle</margin>
For some, instead of <m>turpentine oil</m>, use some <m>spike lavender oil</m>, which is not as good.</note>


<note>
<margin>left-middle</margin>
This varnish is to be applied cold on the canvas with a very clean fingertip, and spread quickly.</note>


<note>
<margin>left-middle</margin>
The Italians hardly varnish their paintings since they layer their paints very thick and these take a long time to be dry on the inside, even though they have a dry skin and crust on the surface.</note>


<note>
<margin>left-middle</margin>
The varnish is applied with one’s finger in order to thinly layer it, because it will yellow afterward.</note>
</div>




OTHER RECIPES related to varnish outside of Bnf Ms Fr640:

Merrifield discusses varnishes on pp. cclxi-cclxxxi
To quote excerpts in brief:
"The earliest varnish and that which was most universally adopted in Italy was unquestionably the old veronica liquid, which was composed of linseed oil and pulverised sandarac, commonly called "veronice," veronice da scrivener," and "gomma di gineparo." The varnishes of Theophilus are referred to under the name (cclxi) of veronica liquid in the Tabula Imperfecta prefixed to th eLe Begue MS (cclxii) [...]"
"Vernice liquida is also frequently mentioned by Cennini not only as a varnish for pictures (fn. cap. 155) and for tin (fn. caps. 97, 98, 101), but as an ingredient in cements (fn. cap. 107), and mordants (fn. cap. 151), and other works." (cclxiii)

Manuscript of Jehan le Begue (1431)
341. To make a good liquid varnish for painters . - Take glass aromatic, which is dark or dull outside, and inside when broken is clear and shining like glass; put some of it in a new jar, which must stand on the mouth of another jar, which must be well luted to it. The upper jar must be well covered so as to be smoke-proof, and its bottom must be pierced. Then light a fire beneath it, and leave it until the glasse is melted, when you must take two parts of linseed, or (p. 312) hemp-seed, or nut-oil, and heat this oil slowly over a fire, not making it too hot. You must then pour it on to the said glasse, make the fire hotter, and let it boil for an hour, taking care that the flame does not touch it. Then take it off the fire an put it into a clean vessel, and when you wish to varnish any dry painting take some of this liquid and spread it over the painting with your fingers, for if you were to do it with a pencil it would be too thick and would not dry. You will thus have good varnish.
[original Latin provided]

Bolognese Manuscript:
206. To make liquid varnish. - Take of the gum of the juniper [sandarac], two parts, and one part of linseed oil, boil them together over a slow fire, and if the varnish appears to you to be too stiff, add more of the oil and take care not to let it catch fire, because you would not be able to extinguish it, and even if you could extinguish it, the varnish would be dark and unsightly. Let it boil for half an hour, and it will be done. (p. 488)

262. To make good liquid varnish.- Take 2 lbs. of common oil, and 2 lbs. of fresh linseed, and boil them together in a glazed pipkin until it is reduced one-half, and then pour it into another glazed vase, such as a pipkin, and take a tripod and place the pipkin on it, and make a clear fire under it, and when the liquid begins to boil add to it 30 or 40 cloves of garlic, cleaned and scraped fine, and a little roche alum at discretion, and let it boil; and if you wish to know when it is well done, take a hen's feather and dip it in the mixture. If the feather is burnt it is done well; take it from the fire, and before it is cold add to it one pound of sandarac well pounded, a little at a time, and keep continually stirring it round with a (p. 520) stick, and when it is nearly cold add six or eight whites of egg, well beaten and cleared, as they are used for vermilion, and mix the whole well, and then place the varnish for one day in the sun, stir it every hour, and keep it in a cool place, and it will be good. (p. 522)

Marciana Manuscript
394. Modes of making divers varnishes; and first, of "bengivi" (Benzoin), which will dry in the shade
395. Item, a varnish
396. Item, a varnish of benzoin, which dried very quickly and may be used on everything, because it is pale and admirable for all delicate works
397. Item, an excellent varnish which is made without the aid (p. 628) of fire, which dries very quickly without being exposed to the sun, and remains very clear, and with which may be varnished anything painted on panel, pasteboard, or iron (p. 630)
through 405 (p. 636) including varnishes for instruments,

Paduan Manuscript
45-59 Various kinds of varnishes; also mentions how to clean paintings and varnish for specifically "old" paintings (pp. 670-674)
92. An amber varnish: Take common turpentine, make it to boil for a quarter of an hour, add to it some amber well powdered on the marble, boil it for half an hour until the amber is liquefied, and take it from the fire. As soon as it is cold it will become hard; when you wish to use it, dilute it with oil of turpentine in order that it may liquefy, and it will be better to heat it slightly that it may be more manageable, taking notice that while it is hot, it should be passed through a cloth, and the part which passes through will be the best part. Apply it with the pencil or with the warm hand. it is necessary to acquaint you that this composition should be washed in hot water, after it has been well strained, that it may be clean and pure. (p. 688)
93. Another secret to make the true Indian varnish: Take gum lac and oil of spike, both of them clean and pure. The oil must be cleansed from its impurities with an equal quantity of litharge of gold; it must then be redistilled and again left to settle until it becomes clear after being passed twice (p. 688) through the still. Another vessel shaped like this [see illustration] must be procured, and for every 4 ounces of spike must be taken one ounce of gum lac (if it is very yellow and clear there is no doubt of its goodness); the whole is then to be placed over a charcoal fire and to be boiled until the colour is changed, and the varnish becomes like honey. To know whether it is good, put a drop on a knife, and if it remains united it is good; it must afterwords be poured through a linen cloth into a vase of majolica and preserved. Cinnabar is ground up with pure water,r and dried on the stone; then ground for a quarter of an hour with seven times its quantity in varnish. The varnish is then applied with a pencil, and the work is to be exposed to the air for 2 hours in order that the odour may pass away; for the same reason the work is to be kept in a warm place; any colour may then be laid on 5 or 6 times. After this it must be made perfectly clean and again varnished, continually dipping the pencil in oil of spike. Whenever you varnish you must dry the whole perfectly. In using the yellow colour you must wait some time for the dissolution of the gum, or you must dissolve it over a slow fire if you do not wish to wait long. (p. 690)
102. To make the finest Indian varnish (p. 694)
106. Varnish is made as follows (p. 696)

Volpato Manuscript (1685)
p. 742 - interesting dialogue re: preparation of varnishes and whether or not it is "becoming" of the painter to know such things as well as which varnishes are bought and which are made by the painter himself

Brussels Manuscript
To make very good varnish for varnishing gold and all other things (p. 838)
To make a varnish with mastic for oil paintings (p. 840)


QUESTIONS:

1. Over which colors does the red varnish work best? To what effect?
2. To what extent can general varnish recipes be adapted to the red varnish recipe in Bnf?
3. Little indication in recipes themselves as to what purpose varnish fulfills - can we discern this be reconstructing the varnish itself?
4. Some of the varnish recipes mention the treating of "old" paintings - how closely is a knowledge of varnish tied to what we may call conservation practices or at least a knowledge of "restoration" even in the early modern period?
5. What can we make of "Indian" or "Chinese" varnish as distinguished from others?
6. In the Volpato Manuscript, there is a dialogue between a master painter (it seems) and an apprentice in which varnishes are discussed - the painter explains to the apprentice that varnish can either be made or bought, depending on its intended use, but nonetheless, it is good for the painter to know how to make varnishes. What can we draw from this conversation as to the priority of knowledge within the workshop in terms of procedure but also person?
7. Most of the recipes explain that the varnish should be applied by hand, without the use of an instrument such as a pencil. What can we draw from the tactility of this application?
8. Many of the recipes identify the varnish as "liquid" - does this distinction imply that there is a solid varnish alternative? Or perhaps that when not in use the varnish itself solidifies? Is the use of "liquid" in the title of the item a reminder to the practitioner that the varnish must be in a liquid state in order to be effective?

MEETING 11/7/15 KK + SS
We are thinking about the presence of gold in the ruby recipe - how much gold is needed? Initially, Joel and Katie thought a large amount of gold would be needed but in discussing, Katie and Siddhartha rethink that a small amount of gold is needed based on historical weight of a grain (24 grains = 1 denier, which we take to be a pennyweight). We therefore think the amount of gold needed is small and feasible given the constraints of our lab and resources. Additionally, we are questioning why minimum is not explicitly called for in the ruby recipe - is this a mistake on the part of the author practitioner? is it assumed that the minium present in the above recipe (emerald) is present in the below recipe (ruby)? if there is no lead in the ruby recipe, how will it be glass? would it be shiny? We are thinking to retry the ruby recipe with the agreed upon small amount of gold AND the same amount of lead as called for in the emerald recipe.

Ratio of quartz powder to lead to alkali salt is 1:3:1 - tremendous amount of lead in this - which accounts for the shininess, which is the difference from bottle glass - can we relate this to notions of "luxury" and market? will it be the refractive index and integrity of color that distinguishes this glass from "bottle" (low) glass?

Is what we are making gold ruby glass? If so, how does this factor into our discussion/ inclusion of enamel in our single annotation

Look at the Lycurgus cup re: shift between green and red re: particles of gold that are effecting the optical properties, accounting for perceived color change

We are interested in various instances of color change (re: Lycurgus cup) and pouring (hot) vs. poured (cold) glass variations in color (from red to green)
**Dichroic glass - has to do with colloidal gold and silver