SUSIE'S REPLY: Mary - There are several answers to your paint and palette questions.
- Many artists prefer to squeeze out fresh watercolor paint for each new painting and simply discard unused and polluted colors when they finish.
- Others choose to squeeze a generous amount of paint into the wells and carefully wipe the mixing area with a sponge or paper towel being careful not to get extra water in the wells when cleaning their palette. They also try to keep the paint moist between painting sessions by misting them with water and/or placing a damp sponge in the mixing area before they cover the palette.
- I prefer to paint with dry paint (tube paint squeezed into the wells and allowed to dry hard) and I rejuvinate the colors with a wet brush as I need them. By allowing the paint to dry I have far less wasted and polluted paint washing down the drain.
My painting methods and techniques do differ from many of the watercolor books and instructors. I don't think there is a wrong method, if it works!
As for what to do with the left over paint in the mixing area. I prefer to discard it. Unless I'm painting a series using the same colors I'll want to start with fresh colors anyway. AND I don't clean my palette immediately (while the paint is damp) I like to wait until the next time I paint then wipe away the dried used paint with a damp paper towel or a sponge. This allows me to pick up any splashes of dried paint that may be sitting on top of another color in my palette with a dampened brush. I find I don't have as much waste this way. I only take my palette to the sink and rinse it when it is really full of messy polluted cross-overs. Even then I have very little paint loss.
I hope that helps. You should find what works best for you and your painting style... it just takes practice and LOTS of it!
Good luck and enjoy the process!