See VARNISHES folder in Student files → Reference → Materials

SP18 Imitation jasper lab work (10r_1)

Varnishes

GOALS

Longer-term - closer examination of varnishes in the ms
Short-term for 2/16/18 activity - compare effect of turpentine varnish vs. aspic varnishes in imitation jasper

General

http://cameo.mfa.org/wiki/Varnish

Any transparent protective or decorative coating. Varnishes are composed of a resin dissolved in a liquid which dries to form a hard glassy film

Varnishes fall into two categories:

1. Oil-based varnishes

Resin dissolved in oil, such as linseed or spike lavender

2. Spirit varnishes

Resin dissolved in solvent or spirit, such as alcohol or turpentine

“Spike lavender” and “Aspic” (from M&K glossary)

Aspic (mod. aspic) = “spike lavender” i.e. Lavandula latifolia, formerly L. spica (CS)

Nom vulgaire de la grande lavande. Il n'est guère usité que dans cette locution, Huile d'aspic. Dict. Acad. fr, 1835. — (OED aspic, n2): The Great Lavender or Spike (Lavandula Spica), a plant from which a volatile aromatic oil is obtained. (1819 A. Rees Cycl. III, Aspic...grows in plenty in Languedoc). — Cotgrave.

Huile d’aspic (f.) (U) = “spike lavender oil” See also: aspic. - PHS 06/06/16: 2016 CC

2016: Huile d'aspic was used as a different way of cleaning paintings. See "Secrets Concernant Les Arts Et Métiers

For more information about varnish components:

See Student Files/Reference/Materials info Turpentine+resins+balsams

In Fr. 640 and entry 10r_1

Fr. 640 describes and uses both and others (mixes)
Imitation Jasper says to use:

<m>clear turpentine</m> or <m><pa>spike lavender</pa> varnish
Possibilities: turpentine on its own, varnish made with turpentine, or varnish made with spike lavender

Varnish Research

Varnishes_aspic+turpentine spreadsheet (in Student Files, reference, materials/info)

Created by THU and NJR in SP18
“Spike” sheet contains all entries containing spike lavender (with notes about varnish application)
“Turp” sheet contains all entries containing turpentine (with notes about varnish application)
“PW17 varnish group” contains info from PW17 BnF index

Recipes and making

For reasons of time and effort limitations, we have chosen one representative varnish of each type (one of turpentine and one of spike lavender oil) that have been previously made in the lab (so that we know we will actually have a usable varnish)

Isabella and Charles used Teresa Soley’s varnish prepared in spring 2016

Teresa’s varnish (Soley safety protocol) is based on 056r_a2 “varnish for distemper” -it is unheated and uses both turpentine and spike lavender oil

Varnish made by Emilie Foyer in FA15 (Foyer varnish safety protocol)

Aspic varnish - Based on recipe on p004r

thus aprox 1 to 3 ratio

45g of lavender spike oil

15g of Sandarac

Recipe

- heat lavender spike oil to 140 degrees C in a beaker in the Fume Hood

- as it begins to simmer put in powdered sandarac gum so that it soon melts.

- stir using chopstick continuously over a charcoal fire (Hot plate) until the sandarac is well melted, increase to 150 degrees if the sandarac does not melt at 140

Turpentine varnish - Based on p003r

Venice turpentine: 80g

Turpentine oil: 40g

Recipe:

- Take (a pound of) Venice turpentine (2 to 1 ratio)

- Heat in a pot until it simmers, （aprox 150 degrees C) in a beaker in the Fume Hood

- put in (half a pound) of the whitest turpentine oil you can find

- stir all together well on a charcoal fire (In our case, a hot plate)

- If too thick add more oil. If too thin, add more turpentine.

Ana Estrades (imitation jasper in FA15 annotation) (Estrades horn+varnish field notes)

Varnish 1

Varnish (p003r in manuscript; consisting of:

20 grams of larch turpentine Kremer - 62000

10 grams of turpentine (distilled oil of) Winsor and Newton. Mixed together and heated up, done by Marjolin and Jenny. We will also try making varnish ourselves)

- At 2 pm, Wenrui and I each took one of the polished pieces and applied varnish on the roughest side, with a brush. The horn instantly acquired a beautiful glossy finished, and I can now understand why the author practitioner says, “the horn gives a luster and a fatty polish similar to jasper.”

- The recipe’s next direction is to paint over the varnished side, which we will do next Monday, when varnish is dried.

Varnish 2 (links to Foyer varnish safety protocol)

Turpentine varnish field notes

80gr of venice turpentine in a 250 ml beaker

40gr of Distilled Turpentine in a 100ml beaker

Hotplate placed under fume hood.

For SP18 imitation jasper, we will follow the recipes chosen by Emilie Foyer as representative samples, modified slightly as below:

SPIKE LAVENDER VARNISH

SP18 version - p004r_1 “varnish of spike lavender oil”

<head><m>Varnish of spike lavender oil</m></head>

<ab>One needs to heat <m>lavender spike oil</m> and as it begins to simmer, put in <m>powdered sandarac gum</m> so that it soon melts. And over a <m>charcoal</m> fire stir continuously until the <m>sandarac</m> is well melted, which you will know by taking a little of the said <m>varnish</m> on a <tl>plate</tl>. And if it is fatty when you handle it with a <tl><bp>finger</bp></tl>, it is ready. And for one <ms>lb</ms> of <m>lavender spike oil</m>, you will put five <ms>ounces</ms> of <m>pulverized sandarac</m>, although some only put in four <ms>ounces</ms>, but this is not so good nor so fatty. This one is promptly dry. <pro>Framemakers</pro>, to avoid the trouble of polishing their <m>ebony</m>, varnish it with this, as do <pro>guitarmakers</pro>. This is not as appropriate for panels as that of <m>fine turpentine</m>, though it is good for the moldings of panels. One did not used to varnish the landscape of a panel when <m>linseed varnish</m> was in use, because it would have yellowed the landscape. But with that of <m>turpentine</m>, one varnishes everything. You can put in <m>pulverized mastic</m> extracted in tears or otherwise, and it will be more dessicative in place of <m>sandarac</m>.</ab>

<ab>If you want to varnish on <m>plaster</m> or a wall, first put on your very hot <m><fr>colle de retaille</fr></m>, because if cold it would not penetrate the wall, & when you would put your <m>varnish</m> on, it would come off.</ab>

<ab>

<m>Varnish of spike lavender oil</m> is not as appropriate for colors as that of <m>turpentine</m>, for <m>spike lavender oil</m> <del>makes them die</del> <add>eats away at</add> the colors since it is too penetrating.</ab>

Ingredients:

1lb=16oz, 16oz of spike lav oil and 5oz of powdered sandarac gum → 5:16 ratio gum to oil
48g spike lavender oil (Kremer 73800)
15g sandarac gum (TALAS #TCD051001)

Process:

Heat oil in glass beaker on hot plate with glass thermometer until it simmers in the fume hood
Add gum, stir on heat until dissolves

Gum sandarac (chemwatch)

Flash point = Not Available
Boiling range = Not Available

Spike lavender oil

Flash point = 57C (Kremer SDS); 34.44C (Dipentene SDS - CAS 7705-14-8)
Boiling range = 158.5-159.5C(Camphene SDS - CAS 79-92-5)
Kremer autoignition point = >200C

TURPENTINE VARNISH

SP18 version - p003r_a2 “varnish for panels”

<ab>Take a <ms>lb</ms> of <m><pl>Venice</pl> turpentine</m> & heat it in a <tl>pot</tl> until it simmers, and put in half a <ms>lb</ms> of the <m>turpentine oil</m> of the whitest you can find, and stir it all together well on a <m>charcoal</m> fire and take it off immediately. And <del><fr>elle</fr></del> it is done. But if it seems too thick to you, add in a little more <m>oil</m>. Similarly if it is too clear, you can thicken it by putting a little <m>turpentine</m>. Thus you will give it whatever body you want. It could be made well without fire, but, when heated, it is more desiccative. It is appropriate for panel paintings and other painted things without distorting the colors or yellowing. And it dries both <env>in the shade</env> and <env>in the sun</env>, and <tmp>overnight</tmp>, and <tmp>during the winter</tmp> as well as <tmp>in the summer</tmp>. It is usually sold 15 <cn>sols</cn> a <ms>lb</ms>.</ab>

<ab>
<margin>left-bottom</margin>
A little more <m>turpentine</m> than <m>turpentine oil</m> is needed in order to give body to the <m>varnish</m>, which needs to be applied with <tl><bp>finger</bp></tl> in order to spread it thinner and less thick, for when it is thick, it turns yellow and sticks. One does not <m>varnish</m> to make paintings shine, for it just takes the light out of them.</ab>

<ab>
<margin>bottom</margin>
But it is used to enhance colors which have soaked in and to keep them from dust. <m>Mastic varnish</m> does not resist <env>rain</env>, whereas that of <m>oil</m> and <m>rosin</m> does.</ab>

Ingredients:

2:1 ratio of venice turpentine to oil of turpentine (distilled turp)
40g venice turpentine (Kremer 62010)
20g distilled turp (Winsor&Newton)

Process:

Heat venice turp in glass beaker on hot plate with glass thermometer until it simmers (presumably before boiling at 150C) in the fume hood
Add 20g distilled turp, stir on heat, then remove quickly

Distilled turp (chemwatch)

Flash point = 30-40C
Boiling range = 154-170C

Venice turp

Flash point = 50-59C (Kremer SDS); 46C (Dipentene SDS - CAS 7705-14-8)
Boiling range = 178C (Dipentene SDS - CAS 7705-14-8)

February 14, 2018 field notes

Conducted in the lab by Hannah Elmer and Naomi Rosenkranz following the highlighted recipes above
Please see videos and photos in the SP18_varnishes_HE+NJR Flickr album
SPIKE LAVENDER VARNISH

Sandarac gum is in small tears. To powder it, the tears were placed in two plastic ziptop bags and pulverized with a hammer. This was followed by additional grinding with a mortar and pestle
5:25pm Spike lavender oil placed on hotplate. 25C, can see evidence of heat ripples within the liquid
5:27pm 50C
5:29pm 100C
5:31pm Can see small bubbles, steaming/vaporizing
5:33pm More vaporization
5:36pm Increase in vaporization and small bubble formation
5:39pm Simmer; sandarac gum added, and stirred
5:40pm Taken off heat and placed beaker in bowl of sand to prevent heat shock to glass
5:47pm Poured the varnish into smaller glass vials, which had been warmed with almost boiling water on the exterior to prevent heat shock
Left uncapped vials to cool in sand
Capped around 7:20pm when they were warm to the touch

TURPENTINE VARNISH

The venice turpentine is quite stiff and not very viscous, the consistency of very thick crystallized honey or of sugar at the soft-ball stage when making candy (see photos and videos of trying to manipulate the venice turpentine)
6:14pm Venice turpentine place on hotplate
6:16pm Beginning to liquify; 35C
6:18pm Entire mass has liquified; 80C
6:19pm Small bubbles starting to form; 100C
6:21pm Increase in small bubbles, vaporizing
6:25pm Added distilled turpentine, stirred
10 seconds later removed from heat and placed beaker into sand to prevent heat shock
6:27pm Poured the varnish into smaller glass vials, which had been warmed with almost boiling water on the exterior to prevent heat shock
Left uncapped vials to cool in sand
Capped around 7:20pm when they were warm to the touch