6

While more historical artists likely didn't understand the chemical processes behind the behaviors of the two options, the biggest reason is permanence. Dyes are organic substances that are either soluble in their medium or in their application. This means the structure of it breaks down as part of the application. The structural breakdown, coupled with the ...


2

Egg tempera is well-known to be quite stable under normal circumstances once it has dried. However, the fresh tempera can easily go bad, especially in warmer conditions: To prepare the tempera paint, dry pigment was mixed with water and egg yolk. The problem of preserving the colours during the painting process was handled with different methods. Egg ...


1

Try mixing the unfermented indigo powder with water in a bowl, and 'beating' it, using a smaller bowl to scoop it up and pouring it back until the mix turns blue. Consider adding lye [NaOH] or slaked lime [Ca(OH)2] to help the fermentation process. The effectiveness might depend on how the unfermented powder was produced, though.


1

Other than a material safety data sheet (MSDS) or a completely outfitted laboratory and mad science skills, there is generally no way to know for sure what chemicals are actively producing color effects or passively integrated as fillers / extenders / driers. Technically, stores are required to give out manufacturers MSDS upon request. If they don’t, you can ...


1

As I understand it, dyes work via chemical reactions with the materials around them--the type of carrier liquid, chemicals within that carrier liquid, the material that they are being applied to, the atmosphere, etc. That means that it is much more difficult to ensure that you can get the same color from one day to another with dyes. You mention indigo--...


1

Most artists used the best materials for the job they could afford. While dyes were often cheaper, you would often know that they would lose colour in the next few years, while pigments were often known to hold colour for a long time. But all painters were limited to what they could get and could afford so some would have gone with dyes and their faded ...


Only top voted, non community-wiki answers of a minimum length are eligible