vision of the naked eye does not suffice to analyze the colors of a picture.
When I had the pleasure of showing this experiment with Mulready's pictures to Prof. Tyndall, he drew my attention to the fact that one single color, namely, the blue of the sky, was not affected by the yellow glass. The blue of the sky was almost the same in both pictures. I could not at once explain the cause of this, but I discovered it afterward. The fact is, it is impossible to change the sky-blue of the first picture so as to form a color that looks like it when seen through a yellow glass. If more white is added, the sky becomes too pale; if a deeper blue is used, it becomes too dark. Mulready was thus forced to content himself by giving to the sky in his later pictures the same color as in the earlier ones.
If we look at Mulready's earlier works through the same yellow glass, they lose considerably in beauty of coloring: the tone appears too weak; the shadows brown; the green, dark and colorless; we see them as he saw them, and understand why he became dissatisfied with them and changed his coloring.
It would be more important to correct the abnormal vision of the artist, than to make a normal eye see as the artist saw when his sight had suffered. This, unfortunately, can only be done to a certain extent.
If it is the dispersion of light which, as in Turner's case, alters the perception of Nature, it can be partly rectified by a kind of diaphragm with a small opening (Donders's sthenopeical spectacles).
In cases of astigmatism, the use of cylindrical glasses will completely correct the aspect of Nature, as well as of the picture. Certain anomalies in the sensation of color may also be counteracted to some extent by the use of colored glasses; for instance, by a blue glass, when the lens has become yellow, as in Mulready's case.
If science aims at proving that certain works of art offend against physiological laws, artists and art-critics ought not to think that, by being subjected to the material analysis of physiological investigation, that which is noble, beautiful, and purely intellectual, will be dragged into the dust. They ought, on the contrary, to make the results of these investigations their own. In this way art-critics will often obtain an explanation of the development of the artist, while artists will avoid the inward struggles and disappointments which often arise through the difference between their own perceptions and those of the majority of the public. Never will science be an impediment to the creations of genius.—Macmillan's Magazine.
