How do you think old painting masters did organic shapes?

Question

In watercolor, we use saran wrap a lot. What do you think they used back in the day, like 100+ years ago?

Answer 1

They study an organic shape for a prolong period of time, and made their brushstroke as precision as possible. Tell you the truth, they make much better art supplies back then.
You can also try bleach parts of it with thinned bleach or strong slaine. Or try gum (not chewing gum, I'm talking about a glue) to resist the paint.
I don't think water became popular until recent centries.

Answer 2

Sarong Wrap