Distemper painting - Skill Building
Date - Monday 29th February
Location - Laboratory in Chandler

We painted distemper on a section of panel that had been prepared with a gesso layer followed by a size layer of rabbit skin glue.
We Began with the shadows, using the manuscript as a guide, but also following the instructions and advice of Dr Erma Hermens who was present in class via Skype as our expert maker.
We used a portrait of a young man as a model.

Ms section that we followed on distemper:
<title id=“p093v_a1”>Faces [painted] with distemper</title>

<ab id=“p093v_b1”>Because colors [painted] with distemper dry quickly and one would not have enough time to complete the shadows and touches on the face, one wets the reverse of the face, on canvas, with a wet sponge. Then, with a small brush, one does the shadows, which don’t come off. Then one lays the flesh tones, which does not prevent the already painted shadows from showing [through]. And one touches again the more prominent areas with brighter flesh tones. And with another brush one does the shadows in hatching. The strokes [that make up] the shadows do not come off because they are [made] of bistre, which stains the canvas like rust. The said bistre is good for painting the shadows in distemper, for in oil it lacks body and would dry with great difficulty. One should mix the said bistre for shadows with ocher de rux and a little sap green. The best bistre is the fat shiny one from the fireplaces of large kitchens. It is difficult to grind and grates on the marble slab.</ab>

Our process was quite different because we are working on panel and not on canvas. As such, we could not follow the instruction to wet the reverse of the canvas with a sponge. So we worked on a dry support. (Perhaps we could have dampened the support a bit at stages anyway?)

Despite complexities and questions that we have regarding the term ‘distemper’, as it seems to have been variously used historically to describe different aqueous techniques, we have decided to use rabbit skin glue as the binder here. This seems to be what the Ms is referring to.

Following the Ms we first laid in shadows. The Ms calls for ‘bistre, which stains the canvas like rust’, mixed with ‘ochre de rux and a little sap green’. According to the Pigment Compendium, bistre was made from wood soot, preferably beechwood. The Pigment Compendium also notes that: “Harley, in surveying British documentary sources, found little mention of the term bistre before the seventeenth century, and then only in works with a strong French connection.’ This suggests that it was more commonly used in France before the seventeenth century, it is therefore unsurprising to find it in our manuscript.

In place of ‘bistre’ we had a choice between using charcoal black (or lamp black?) and iron oxide. We chose to use iron oxide. We combined the iron oxide pigment with red ochre (ochre de rux) and sap green pigment. The ratios are not specified in the Ms and so we had to adjust based on our own, personal, assessment of the kind of colour we wanted. The colour that we aimed for in the shadows was quite similar to an early Italian ‘verdaccio’ but slightly darker. It was generally thought unnecessary to further grind the pigments since they were commercially bought and already finely ground. However we chose to further grind them because we thought that simply mixing the pigments with glue would still give us ‘gritty’ results, and also because grinding the pigments together before adding them to the binder would ensure that they were very well combined. Therefore we ground our pigment mixture together with water. An interesting result was that the colour changed significantly when we ground the mixture. It shifted from a markedly red colour to a cooler, more brown hue. We then mixed the ground pigment with rabbit skin glue, heated to (60 degrees celsius?). To keep the paint warm while working which is necessary to keep it fluid, we put our paint in a small glass jar in a cylinder of very hot water - effectively a bain-marie. In terms of quantity of rabbit skin glue added, we kept putting in syringes until it ‘felt right’. This was an assessment I basically made on intuition - intuition based on familiarity with other paint media and the handling properties one requires of a paint. This was a very inexact judgment call but since no quantities are specified in the Ms it was all that we could do. Such decisions, based on feel, intuition, and experimentation, are the kinds of decisions that have to be made in the moment when working with materials. However, I imagine that in historic craft situations, one would be following a master craftsman with a great deal of experience. We did in some sense mimic a ‘master craftsman’ and ‘apprentice’ situation by having guidance from Dr Erma Hermens given via Skype.

The handling properties of the shadow layer were in fact quite good. Perhaps we had added too much liquid glue to the binder, but as I applied it with my brush the paint felt like a thick watercolour. I was able to vary the intensity of the shadows by varying the amount of glue I added to the pigment to adjust the thickness of the paint. I used a small brush as directed by the Ms and chose a soft one with good results. I found myself taking quite a lot of ‘creative’ license because there is no real guidance in recipe 93v about how to apply the paint. I therefore used my own knowledge of painting to ensure that I followed the contours of the face with my brush, varied intensity of shadow in a gradual way, and so forth. This made me think about how and to what extent one can transfer knowledge and ability in one medium to another. I think I was using the distemper in a similar way to how one would use egg tempera, but without the typical hatching. The similarity to egg tempera painting was to do with drying time - like egg tempera, the distemper dried fairly quickly on the support and so one has to work quite quickly and deliberately. This is very different to oil painting where one can return and re-work passages.

The next layer applied was the base flesh tone, put on after the shadows had dried. We were following this instruction in the Ms: ‘Then one lays the flesh tones, which does not prevent the already painted shadows from showing [through].’ This time we made the judgement about colour and therefore pigment mixture based on the (Mantegna?) portrait. The skin tones were ochre-like with some greenish tones. We mixed together chalk white, yellow ochre and green (which green?). We found that a large amount of chalk was needed to shift the colour of the mixture, at least in dry pigment form. It seems to have considerably less tinting strength than lead white. We ground these pigments together in water before adding to the glue binder, as with the dark for the shadows. The hue did not change so dramatically but it did all appear brighter and more yellow once mixed with water. Then we mixed with rabbit skin glue and kept the paint in a bain-marie as described above. We painted this colour over the entire painting, covering all the shadows. We kept the paint layer quite thin to allow the shadows to show through. The paint was somewhat thicker and more difficult to handle than the shadow layer - I think this is because of the large quantity of chalk pigment we put in, which was necessary because the colour was still not as pale as we would have liked it to be. If we used lead white, perhaps the handling properties would be different, and the layer would have been more opaque.

The next layer was a mixture of chalk white, red ochre and venetian red (susbtituting vermillion). We ground the pigments together and added them to the rabbit skin glue binder as described above. We applied this as a continuous layer over the whole face once again. I did find myself instinctively varying the thickness of this layer in order to try and allow the modelling from the lower layers to show through. Perhaps this was not the correct way to proceed, but it was very difficult to remove any desire to have a successful final result, even though this experiment is supposed to be primarily about process.