Choosing the Right Pigments
Rather than grapple with the vast range of pigments available today, particularly through art supplies online, painters will generally make better headway by getting to know a small number of pigments that meet most requirements. Ideally, the selection should be based on:
1. Properties of the pigment concerned: hue, mixing properties, drying time, paint strength, permanence, transparency/covering power
2. Adverse effects of mixing certain pigments: some mixtures discolor
3. Cost
Some General Advice
Whites
Titanium white dries fast, and is the most opaque.
Flake white is the quickest drying, but discolors if not protected by oil. Zinc white gives the purest color mixes but is only half opaque, dries slowly and will crack if applied too thickly.
Dead coloring
For blocking out large areas of a canvas prior to more detailed painting, the following are colour-fast, generally cheap (except the cadmiums), and have good covering power: ivory black, flake white, Indian red, yellow ochre, Naples yellow light, cadmium light red and yellow, emerald green and Sevres blue.
Glazes
Pigments in glazes need to be colour-fast and transparent. Dutch vermilion, Rembrandt rose, ultramarine deep, Rembrandt blue, gold ochre, raw sienna, lemon yellow, terre verte, burnt umber, raw umber and Rembrandt green are the traditional favorites. Many have been replaced by pigments listed below. Dutch vermilion, lemon yellow and zinc white are only half transparent.
Paint Strength Grouped by Drying Times
Bazzi (see below) provided this grouping:
Rapid
Umbers: tough & flexible.
Aureolin: hard & erratic.
Burnt sienna: hard & fairly strong.
Flake white hard & flexible
Average
Cerulean fairly flexible
Raw sienna: tough & fairly strong.
Cobalt blue: hard & fairly brittle.
Cobalt violet: rather brittle.
Red iron oxide: strong
Chromium oxide: flexible & fairly hard.
Viridian: flexible & fairly hard.
Naples yellow: strong.
Quinacridones (permanent rose & magenta, rose doré) hard & fairly flexible
Slow
Green earth: soft & flexible.
Cerulean: soft & non-elastic.
Yellow ochre: fairly strong.
Alizarin: soft.
Ivory black soft & brittle
Cadmiums hard & fairly flexible
Titanium white brittle
Very Slow
Ivory black: soft
Zinc oxide: hard & brittle.
Lamp black: soft.
Permanence
Testing by Wilcox (see below) has suggested that many watercolor (and by extension oil) paints may be unsatisfactory — fugitive, badly blended, with poor spreading and transparency.
Exceptions — pigments that are worth selecting from art supplies online — include the following. (T is Talens, R is Rowney and WN is Windsor and Newton. Unless otherwise indicated, all are first artists's quality. The order does not matter, though Wilcox prefers WN to the more oily T.) Grouped by transparency, the recommended pigments are:
Transparent Colors
Aureolin (R and WN)
Permanent rose (WN and R)
Permanent magenta (WN)
Scarlet lake (WN)
Cobalt blue (R and WN)
Ultramarine (WN and T and R and Georgian)
Viridian (R and T)
Light red (WN and R and T)
Gold ochre (T)
Burnt sienna (WN and R and T)
Burnt umber (Georgian and T and WN)
Opaque Colors
Naples yellow (R and WN and T)
Cadmium yellow Light (R and T and WN)
Cadmium yellow (WN and R and T)
Cadmium orange (R - I have WN now)
Cadmium red (R and T and WN)
Cadmium red Deep (WN)
Cerulean blue (R and WN and T)
Chromium oxide Green (WN)
Indian red (WN and R)
Yellow ochre (Georgian and WN and R)
Raw umber (Cotman and WN and R and Reeves)
Ivory black (R and WN and Cotman Georgian)
Discoloration
Bazzi warns that discoloration occurs with these mixtures:
Cerulean with Indian red or ivory black.
Light cadmium yellow with red earths or cobalt violet.
Medium cadmium yellow with raw & burnt earths, also cobalt violet.
Cadmium orange with burnt sienna.
Ultramarine with aureolin.
Ultramarine with zinc white (fades).
Grounds with red or brown earths, especially with oils, absorb mid-shades of overlying paint and darken.
Viridian and cadmium yellow are stable only in zinc white.
Naples yellow and cobalt violet are discolored by a metal spatula.
