Opaque is explained in the Merriam-Webster Dictionary as "exhibiting opacity : blocking the passage of radiant energy and especially light". As such, opaque pigments let less light through and allow better coverage in oil painting.
Transparent is explained in the same dictionary as "a. having the property of transmitting light without appreciable scattering so that bodies lying beyond are seen clearly; or b. fine or sheer enough to be seen through". As such, transparent pigments allow colours underneath to show through and are ideal for glazing.
I remember how surprised I was to learn that oil colours actually vary in the level of opacity. Some are more translucent, whereas some are more opaque than others. For example, there are several types of white pigments. Some of them are opaque, but some are transparent. Unfortunately, there is no easy way to identify the opaque colors versus the transparent ones other than by memorization. To make it a little bit easier, I have compiled a list of common pigments divided into two sections; opaque and transparent.
Cadmium Yellow
Cadmium Red
Cobalt Green
Ivory Black
Mars Black
Raw Umber
Titanium White
Vermillion
Zinc White (semi-opaque)
Transparent
Alizarin Crimson
Burnt Sienna
Cobalt Blue (semi-transparent)
Cobalt Violet (semi-transparent)
Davy’s Gray
Hansa Yellow
Phthalo Blue
Phthalo Green
Prussian Blue
Ultramarine Blue (semi-transparent)
Permanence
I was equally surprised to learn of a varying degree of colorfastness or permanence within the vast spectrum of oil colours. It seems to me that oil colour is oil colour, but that's simply not true. Again, there is really no pattern to the colorfast quality of pigments. A good quality manufacturer will provide only the best pigments recommended as permanent for artists’ use, with a rating of "extremely permanent" or "permanent". However, there are very few colours which do not reach this standard and are provided only because of the lack of permanent pigments in certain colour areas. Sap Green and Carmine are examples of oil colours that are sold by manufacturers of fine oil paint but rate low on the permanence scale.
An artist may choose one pigment over a similar one because of the permanence rating. For example, Titanium White, Underpainting White and Zinc White all are rated by Winsor Newton as being extremely permanent (AA), but Foundation White and Flake White are only considered permanent (A).
Often a manufacturer will manipulate a pigment to offer an alternative to one with a weaker permanence. For example, Winsor Newton provides Permanent Sap Green with an A rating as an alternative to Sap Green, which they also sell but with a B rating (Moderately Durable).
Go To Page: 1 2
