What exactly is gesso? You may think the word sounds Italian and you're right! It is. It means chalk. So, obviously it was likely invented in Italy way, way back. And rumor has it, it was.
A mixture of animal glue (ugh!) and white chalk or plaster were mixed together to make it. It was a clever concoction that paint could grab on to..it had tooth or a slightly rough surface when it dried. It was also great as a sealer on other porous surfaces like wood and canvas.
In the mid 1950's, a more modern water-based acrylic version was developed. It's still used the same way and for the same purposes. Basically, it's an artist's paint primer.
I use it to add extra strength to the pages of my altered books and in my art journals.
It's great because it keeps the paint from soaking through the paper.
The most popular color remains white, although black and burnt umber and a buff shade are used more and more.
It's actually a lot of fun to tint your own. Try adding unsweetened Kool-Aid to it, or add drops of tube watercolors. It works really well with your acrylic paints too!
Cleanup is simply soap and water. Happy painting!