HOW TO TEST IF PAINT COLOR IS OPAQUE OR TRANSPARENT

The following information is important for glazing and provides the information

you need to make your own glazes dependent upon your own designs' color

palette.  You will want to use colors which are transparent over what your basecoat color is so trial and error comes in to play.  Just "using" any color of glaze is not the primary idea of glazing....  Use your basecoat color and the color you are wanting to use as the glaze and "test it" as is shown below.  

How to Test if a Paint Color is Opaque or Transparent

How to Test if a Paint Color is Opaque or Transparent

Image: © Marion Boddy-Evans. Licensed to About.com, Inc.

Different pigments have different covering properties. Some are extremely transparent, barely showing on top of another color. Others are extremely opaque, hiding what's beneath. Considering this, and not just what the color is, can enhance a subject. For example, using a transparent blue in a sky gives a greater feeling of airiness than an opaque blue will. Compiling a chart of the colors you regularly use, such as the one above, shows at a glance how transparent or opaque a color is.
You Will Need:

• All the colors you usually paint with.
• Medium-size brush.
• Cloth to wipe the brush on.
• Jar of clean water.
• Pen to record the color names.
• Piece of white paper. If you've got about a dozen colors, you want a sheet about A5 size.
• Ruler (optional, straight lines aren't essential).
• Hairdryer (optional, for acrylics or watercolors).

How to Make a Chart:

• Sort out your colors in an order that makes sense to you, such as the color spectrum (rainbow).
• Mix up a little of each color. Paint a vertical stripe of each. Wait for them to dry.
• Paint horizontal stripes for all the colors, in the same order.
• If you're using a ruler, wipe the edge after each stripe so you don't contaminate the next one.
• Record the names of the colors next to each stripe.

Check the Results:

• Opaque pigments are dense and tend to block out other colors. This makes them ideal for subjects that are solid and heavy, such as tree trunks.
• Transparent pigments are light and airy, barely showing on top of other colors. This makes them ideal for atmospheric subjects such as a misty morning or diaphanous fabrics.
• Semi-transparent are somewhere between the two.
• With time, you won't have to refer to the chart, but will instinctively know the properties of a particular color. Until then, stick the chart up on the wall where you can see it while you're painting.

 Paint Tube Labels -- Opacity and Transparency Label Information