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Home Methods and Results Trials Of Pigments O. N. Rood's Experiments
 
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O. N. Rood's Experiments

In his 'Modern Chromatics', pages 90 and 91, Professor Rood gives the results of a few trials which he made as to the effect on washes of water-colours laid on ordinary drawing-paper of three and a half months' exposure to summer sunlight.

These pigments were unaffected:

Cadmium yellow, yellow ochre, Roman ochre.

Indian red, light red, Jaune de Mars.

Terre verte.

Cobalt, French blue, smalt.

Burnt umber, burnt sienna.

The following pigments were all affected. The sequence represents the amount of alteration, the list commencing with those colours which suffered but little change:

Name of Pigment

Nature of Change

1.

Chrome yellow

Slightly greenish.

2.

Red lead - -

Less orange.

3.

Naples yellow -

Slightly greenish brown.

4.

Raw sienna - -

Fades, yellower.

5.

Vermilion - -

Darkens, brownish.

6.

Aureolin - -

Fades slightly.

7.

Indian yellow -

Fades slightly.

8.

Antwerp blue -

Fades slightly.

9.

Emerald green -

Fades slightly.

10.

Rose madder -

Fades slightly, purplish.

11.

Sepia - - - -

Fades slightly.

12.

Prussian blue - -

Fades somewhat.

Name of Pigment

Nature of Change

13.

Hooker's green -

More bluish.

14.

Gamboge - - -

Fades, greyish.

15.

Bistre - - -

Fades, greyish.

16.

Brown madder - -

Fades.

17.

Neutral tint - - -

Fades.

18.

Vandyke brown -

Fades, greyer.

19.

Indigo - - - - -

Fades.

20.

Brown pink - - -

Fades greatly.

21.

Violet carmine - -

Fades greatly, brownish.

22.

Yellow lake - - -

Fades greatly brownish.

23.

Crimson lake - - -

Fades out.

24.

Carmine - - -

Fades out.

Professor Rood adds that rose madder, brown madder, and purple madder were all a little affected by an exposure to sunshine for seventy hours, and that pale washes were completely obliterated by a much shorter exposure to sunshine in the case of carmine, dragon's blood, yellow lake, gall-stone, brown pink, Italian pink, and violet carmine.
Home Methods and Results Trials Of Pigments O. N. Rood's Experiments

Last Update: 2011-01-23