Graduated Color Blends in Fresco

04-14-04, This is what I learned when the colors dry, a week later the color is 20 to 30% lighter. There is a big loss of contrast, most change happens in the first week. Don't use lime cream or paste in dark colors, use lime water. Paint the dark colors first so they have time to absorb.

Titanium white is very opaque, you get the tint color you mix wet when it's dry.
Zinc white is at least 4x weaker than Titanium White while wet.
Lime neutral as a pigment is weaker yet when first applied.
Lime paste, cream and milk are the weakest while wet.
Use Lime water for dark colors. How much will the lime paste 1:1 with pigment lighten it? This is my starting point. It will guarantee a carbonate layer. I've heard to add zinc white to this mix to bring the pigment up to it's final color, forget it. Titanium white will do it better and faster.

The mortar was still not hard after 5 days. Steve said he saw it hard in 2 days by mixing all his pigments in lime paste but he is working in normal weather, it's very wet here. It might be just that simple. So why was neutral lime pigment called the best white? It was the best white they had at the time.

I scraped down the first dry rough coat to make it rough without any carbonate on top. Mortar: 1:1 marble meal and lime paste with 1/4 teaspoon of alum added. Two 1.5 inch diameter measuring cups 7/8ths of an inch high filled, covered an 8 1/4 x 2.5 inch brick with 1/4 inch of mortar.

After seeing how well the casein and pigment lettering secco bonded, I'm tempted to add 10% to the lime water for this fresco. I read where it was supposed to make painting sticky, it doesn't. Casein is very strong, don't use much of it.
Later I decided casein didn't help the mortar and alum did, it made it get harder, faster.

I sanded the trowels with a sponge sanding block to remove any rust and laid on the mortar. Popped out any air bubbles with a pin as it was setting.

4 hours later it was still too wet, this brick holds too much water, I was using 2 year old lime putty, the brick is just too wet. I added another 25% of sand and doubled the alum, that brought the alum up to a level baby teaspoon. Still less the a half of one percent of the total mortar mixed. Now it spreads like room temperature butter and I can finish this tonight. I set the brick on a piece of absorbing paper.