REACTIONS
REACTIONS are responsible for the failure of many colour-schemes because of the extraordinary changes which colours appear to undergo under the influence of their surroundings.
After looking for a time at any strong colour the eye tends to see the opposite of that colouk If after looking at a strong red one looks at a fresh green, the green will appear bluer than it would if the red were not seen first. The direct opposite of red being green-blue, the eye is inclined to see that colour after looking for a time at the red, and so the neighbouring green will appear bluer than it really is.
In the same way a mass of strong green-blue tends to make its surroundings redder. Rose against orange-red will appear more purple than when seen alone. Blue against strong, bright green tends to look more violet.
The remedy for this trouble is perfectly simple—merely add to the injured colour a sufficient portion of the colour which is causing the injury. Thus, a rose-tint which has been turned purple by the violence of a neighbouring orange may be restored by adding to it a sufficiency of orange. As the rose is warmed and reddened the purple effect will disappear. In practice this may be done either by actual mixture of colour or by intermingling by means of spots or fine stripes. Of course, if one were actually dealing with a delicate rose colour, it would be a matter for one's own judgment to decide whether to mix orange with it or to substitute a redder tint for the rose, relying upon the force of the orange in making the red appear rosy.
Colourless spaces can be made to appear as though they were coloured by means of reaction from their surroundings. A space of neutral grey has, when surrounded by a bright and very greenish blue, apparently turned a reddish pink. A complete cure was effected by adding some of the same greenish blue to the neutral grey.
Similarly black, used side by side with greenish blue, has appeared quite rusty. This is a matter of very great importance to all who have to use colour in decoration, and particularly in printed or woven fabrics, for a good working knowledge of the reactions of colour will save much valuable time in seeking for the cause of a defect, and it may even prevent the spoiling of a quantity of valuable material.
It is hardly necessary to supply a table of reactions, as a thorough study of the table of contrasts, with a thoughtful application of its principles, will enable any student to determine the cause of a reaction and to find a remedy.
Ground tints are peculiarly liable to change when patterns are worked over them, and so utterly unrecognisable do colours become under such conditions that even the most experienced eye may be deceived. For a good example take an orange ground, cut it in two, and work a pattern over one half in strong yellow-green, but over the other half in strong reddish purple. If this is done fairly, the experimenter will find it hard to believe that he really used but one colour for the two grounds.
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