Pigment pair · PB28 + PG7
Mixing Cobalt Blue and Phthalo Green
Nine steps from one to the other, worked out with a spectral model rather than by averaging screen colors. Half and half gives #035861. Click any step to open it in the mixer.
The full range, Cobalt Blue to Phthalo Green
Ratios are parts by volume, the way you would put them out on a palette.
This pair stays colored all the way across. You get a range of muted mixtures rather than a gray, which is what you want when a passage has to stay quiet without going lifeless.
The same range with white added
Two parts titanium white to one part of the mixture above. White lifts the value but also takes the chroma down, which is why a tint is never simply a lighter version of the same color.
The same range as a watercolor wash
Roughly one part paint to two parts water, over white paper. Remember that watercolor dries up to about thirty per cent lighter than it looks while wet.
Phthalo Green is much the stronger of the two. The ratios above are by volume, so the first step away from pure Phthalo Green already changes a lot less than the last step towards it. Put out less than looks right and work towards the color; going back costs far more paint.
What you are working with
| Pigment | Index | Strength | Opacity | Lightfast | In |
|---|---|---|---|---|---|
| Cobalt Blue | PB28 | 4/10 | semi-opaque, granulating | excellent | Oil, Watercolor |
| Phthalo Green | PG7 | 10/10 | transparent | excellent | Oil, Watercolor |
A neutral blue, low in tinting strength. Ideal for skies that should not go harsh.
Very strong and artificial in tone. Tame it with red or with an earth color.
Now do it with your own paints
This page assumes two tubes. The mixer works from everything on your palette at once, and from a color you pick out of your own photo.