Staining Watercolor Pigments

QUESTION:
Hi Susie, I've been painting for 6 years and I think I'm finally over the hump where I don't need to classify myself as a rank beginner. (smile) I now have a ton of watercolor paints. How can I determine which are staining or non staining? And could you also tell me how to know if they are transparent or opaque? Thanks, Wanda/ NC

SUSIE'S REPLY:
Hi Wanda, There is a simple test you can do with each of your many tubes of watercolor so you will know which are transparent vs opaque or somewhere in between. You can test each color individually or use a larger piece of paper to test each group of colors by their hues. Using a wide permanent black marker or India ink draw a line approximately 1/4 inch wide for each color you are testing. Add a small amount of water to dilute each paint so that it spreads easily being careful not to add too much water. Allow the paint to dry. If it is transparent you will be able to see the sharp black line through the paint without any residual paint sitting on top of the line. If a paint is semi-opaque you will see only a small amount of pigment on the black line. If the paint is opaque you will see more of a chalky looking residue from the paint over the black line.

There is another simple test for determining if a pigment is staining or non staining. You will find the explanations and the illustrations for both of these tests (Testing Watercolor Paints) on my website. http://www.susieshort.net/watercolor-tips-transparency.html

Good questions! Thanks for asking!
SUSIE