Re: Sunflowers on a White Cloth - casein
Thank you, Steve!
Whether or not to tone your substrate is a very personal choice. My decision stems from the old palette I like to use. It's mahogany and used to be my oil painting palette. It's been impregnated over the years with linseed oil - so it is actually quite water resistant. It's an unlikely choice for a casein palette but - again - a very personal choice - I just really like it and am used to it. The Venetian Red, which is one of my colors anyway, is close in value and color to my mahogany palette. This makes it a little easier to gauge color when mixing.
The six coats is rather arbitrary, I admit. But it seems to be a good amount to fully cover the Claybord panel with no streaking. Also, it gives me a good layer of casein over which to paint. That way, if an area of my painting doesn't receive a lot of paint, there is still a good layer underneath to support it. When my paintings are finished and have cured for 6 weeks, I like to buff them with a small piece of wool. (This brings a lovely satin-y finish to the surface and takes the place of varnishing.) Knowing there is a solid layer of casein to buff gives me confidence - although I've never had any rub-off up to this point.
The few times I've painted on Claybord straight from the packaging I've been frustrated. The surface feels too slick for me and I felt I had less control. This could be explained by my move from watercolor board to Claybord - the former is very absorbent and I may have gotten used to that. I'm wondering, if I tried untoned Claybord now, how I would rate it.
One final reason: I plan for and utilize the slight lifting I can achieve with the Venetian Red. Whenever I need or want, I can bring up that deep warm color as it suits me. This also helps to unify a painting as it can become the mother color - or a component of the mother color. One could use any color to do this with - including black. Like I said at the top, it's a personal choice.
Hope this is helpful,