Draw a solid black line with a broad tip permanent marker.
Dilute your paint to an easy to spread consistency and paint
across the black line, be careful not to use too much water.
Allow it to dry.
If the paint is totally transparent it will be invisible over the
black line.
If it is semi-transparent you will see a hint of color on top of
the black line. The more opaque the paint, the less of the
black line will be visible and the more paint you will see on
top of the black line..
Any paint that is sedimentary in nature will have some paint
particles that do not dissolve and can be seen sitting on top
of the line thus they are classified as semi-transparent.
The more white or chalky the paint the more opaque it is.
Of course even with very opaque colors, the more water you
use to dilute the paint the more transparent it will appear
when painting it on white paper.
Here is an easy way to test the paint in your paint box to find out if they are
transparent, semi-transparent or opaque.
To a watercolor paint for staining properties paint a
brush stroke of a fairly concentrated solution of the
paint you want to test. Let it dry completely. With a
damp stiff brush agitate the surface (gently but
firmly scrub it) and blot it dry. If the paint is highly
staining you won't see much paint removed. If it is
no staining you will see very little paint left on the
paper and without much effort. And the
semi-staining will fall somewhere in between the
two, leaving a light stain.

This test will also tell you the durability of your
paper and how it will stand up to scrubbing to lift
out highlights.
Back to Tips
© Susie Short Studio LLC   -    All Rights Reserved    -     www.susieshort.net