It occurred to me the other day that the Holly Grail Gesso had to use as a binder either Wheat Paste, Gum Arabic, Casein, or Methyl Cellulose, and that rather than rubbing pigments in the ground, I could possibly mix them into paint with one of these four traditional binders. It seemed worth testing the idea, and I already had Wheat Paste for Book Binding, so I ordered Gum Arabic and Casein.
I used a board primed with Holly Grail Gesso and Ultramarine pigment for the test, mixing it with increasing amounts of water and Wheat Paste, Gum Arabic and Casein(left to right).
The Wheat Paste was a little lumpy, and looks grainy, with heavy brush marks .
The gum Arabic went on smooth and adhered well, but adhesion decreased as the dilution increased, and it tended to pool and leave gaps in the coverage(a little Ox Gall helped). The white from the gesso did not seem to mix with the paint, and the colors are rich.
The casein has a white milky color to start with, and produced much lighter very flat colors with excellent coverage. It was made even worse by mixing with the white pigment in the gesso when over brushed. I don't like it, it kills the colors, and pastel tones are not my thing.
I also made swatches of different colors of Rembrandt Soft Pastels(left side), first rubbing the stick on , then smoothing and rubbing hard with my finger. The pastels definitely produced the most intense opaque color and very good adhesion to the board, without getting a chalk look from the white gesso particules, I assume because of the binder in the pastel sticks.
I had started with a swatch of pure Bluempigment rubbed into the gesso(top left), and found the coverage was uneven. The more I rubbed, the worse it got. I had used an Ultramarine Blue from Earth Pigments, which was cheaper than the Sinopia Ultramarine Blues, so I made a side by side test swatches on the bottom, and the basic rule "You get what you pay for" applies here as it does most of the time. The Sinopia Ultramarine produces a richer color with very even coverage, which does'nt seem to degrade with rubbing. That makes me wonder if the swatches with binder would have come out better too.
The lessons are:
1. Binders don't seem to help, so I will use a combination of rubbed raw pigments and pastels for my underpainting.
2. DO NOT SKIMP on pigments, Sinopia's products are definitely better. Plus they tell you precisely the properties and have a much wider range of colors.
I used a board primed with Holly Grail Gesso and Ultramarine pigment for the test, mixing it with increasing amounts of water and Wheat Paste, Gum Arabic and Casein(left to right).
The Wheat Paste was a little lumpy, and looks grainy, with heavy brush marks .
The gum Arabic went on smooth and adhered well, but adhesion decreased as the dilution increased, and it tended to pool and leave gaps in the coverage(a little Ox Gall helped). The white from the gesso did not seem to mix with the paint, and the colors are rich.
The casein has a white milky color to start with, and produced much lighter very flat colors with excellent coverage. It was made even worse by mixing with the white pigment in the gesso when over brushed. I don't like it, it kills the colors, and pastel tones are not my thing.
I also made swatches of different colors of Rembrandt Soft Pastels(left side), first rubbing the stick on , then smoothing and rubbing hard with my finger. The pastels definitely produced the most intense opaque color and very good adhesion to the board, without getting a chalk look from the white gesso particules, I assume because of the binder in the pastel sticks.
I had started with a swatch of pure Bluempigment rubbed into the gesso(top left), and found the coverage was uneven. The more I rubbed, the worse it got. I had used an Ultramarine Blue from Earth Pigments, which was cheaper than the Sinopia Ultramarine Blues, so I made a side by side test swatches on the bottom, and the basic rule "You get what you pay for" applies here as it does most of the time. The Sinopia Ultramarine produces a richer color with very even coverage, which does'nt seem to degrade with rubbing. That makes me wonder if the swatches with binder would have come out better too.
The lessons are:
1. Binders don't seem to help, so I will use a combination of rubbed raw pigments and pastels for my underpainting.
2. DO NOT SKIMP on pigments, Sinopia's products are definitely better. Plus they tell you precisely the properties and have a much wider range of colors.
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