This is my palette I use for all acrylic paints. This setup isn't completely air tight but I like that I can
just flip the latch, open and start painting in seconds.
My palette is made from an A4 plastic folder (I bought this
many years ago, but I have seen very similar in Officeworks), kitchen sponges
cut to fit and a tile or freezer paper (I used Glad Go-Between Freezer Film).
You just need to keep the sponge damp, depending on which paint is used either misting
paint with water or pouring directly onto the sponge may be required.
The paint on the tile is Matisse Structure and has dried
just around the edges of the puddles. The paint on the freezer paper is (from
left to right) Jo Sonja Flow Acrylics, Matisse Structure Acrylics and Matisse
Flow Acrylics and has been left for three (3) weeks with the sponge being wet a
few times.
I have left Atelier Interactive paints on a tile for a month
or more and they have been as good as using straight from the tube (if over
misted they can get runny or if sponge is let dry out they will dry). However,
the sponge seems to stay damp when using a tile.
My test with freezer paper has left the Matisse Structure as
good as from the tube. But both flow formulas have become runny even without
misting.
I prefer to use a tile as I can mix as roughly as I like, it
is easy to clean and there is no setup time. This freezer paper is quite strong
(I previously used wax paper, but it was too fragile and ripped too easily and
also bled through to the sponge) but does required cutting to size each time
but you have no cleanup, just throw it away.
