Paint Properties: Opaque & Transparent Pigments
Mixing colors isn't just knowing that yellow & blue = green. Knowing whether a pigment is opaque or transparent and how color mixtures are effected by these properties is a key element in learning color mixing. Opaque pigments will give you better coverage; transparent pigments are good for glazing . . . but there's a little bit more to how they interact as mixtures.
| Opaque Pigments | Transparent Pigments |
| Cadmium Yellow | Phthalo Blue |
| Cadmium Red | Phthalo Green |
| Raw Umber | Hansa Yellow |
| Titanium White | Alizarin Crimson |
| Mars Black | Burnt Sienna |
| Ivory Black | Prussian Blue |
| Cobalt Green | Davy's Gray |
| Vermillion |
Knowing whether a pigment is opaque or transparent and understanding their property differences will help you when you're mixing tints and shades. If you looked at two opaque pigments which had been mixed together under a microscope, their particles would appear intermingled, lying next to each other. Rays of light will be reflected from each pigment -- white light reflected from the painting's surface will be from all of the particles of both pigments.
Tints or mixtures of opaque colors are usually duller, therefore, than those made of transparent pigments. When a transparent color, such as alizarin crimson, is used to tint white paint, each particle of white is surrounded by the transparent red -- light will pass through the transparent red and reflection will mostly come from the opaque white. The transparent pigment, when mixed with white, does not convey its color effect of its surface color to the mixture but its transparency has much to do with the clarity of tone produced by the mixture.
| Semi-Opaque Pigments | Semi-Transparent Pigments |
| Zinc White | Cobalt Blue |
| Ultramarine Blue | |
| Cobalt Violet |
Pigments that are semi-opaque or semi-transparent have properties found in both opaque and transparent pigments -- tints using zinc white will be more transparent than if you had used titanium white; a semi-transparent pigment will impart more of its surface color to titanium white and reflect more light than a transparent color.
Practical example to see the difference yourself: Many beginning painters use mixtures of zinc white and cobalt blue to create a "sky" color. Substitute titanium white and you'll find that your color reflects more white and is less dull a color. Experiment . . . it is only by remembering these properties that you can control your color effects.
