How can I make the best out of the following three materials that I’d like to use on my artworks?

Can you really make paint with calcium carbonate or baking soda, if so how long would this paint last?

What are some tips for painting over wallpaper?

Why exactly is Renaissance art more realistic and lifelike (especially in its portrayal of human beings) in comparison to Medieval art?

What is the most abstract painting of a portrait you have seen?