Turner and Mulready : the effect of certain faults of vision on painting, with especial reference to their works. The real and ideal in portraiture. The deterioration of oil paintings : three lectures / by R. Liebreich.

  • Liebreich, Richard, 1830-1917.
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Turner and Mulready : the effect of certain faults of vision on painting, with especial reference to their works. The real and ideal in portraiture. The deterioration of oil paintings : three lectures / by R. Liebreich. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    12/50 (page 12)
    elongated, and all details are in the same manner distorted. What iR the canse of this? Has the degree of his astigmatism increased? No ; this does not often happen; but the effect of astigmatism has doubled, and this has happened in the following manner:—An eye which is normal as regards the vision of vertical lines, but short- sighted for horizontal lines, sees the objects elongated in a vertical direction. When the time of life arrives that the normal eye becomes far-sighted, but not yet the short-sighted eye, this astigmatic eye will at short distance see the vertical lines indistinctly, but horizontal lines still distinctly ; and therefore near objects will be elongated in a horizontal direction. The portrait-painter, in whom a slight degree of astigmatism manifested itself at first only by the indistinctness of the horizontal lines, has now become far-sighted for vertical lines, and therefore sees a distant person elongated in a vertical direction; his picture, on the contrary, being at a short distance, is seen by him enlarged in a horizontal direction, and is thus painted still more elongated than the subject is seen; so the fault is doubled. I shall be able to show this more clearly by experiments. The vertical and hoiizontal lines of this diagram (Fig. 4) are reflected with equal distinctness upon the screen by the spherical apparatus. Those among my audience who have a decided form of as- tigmatism will, nevertheless, see them differently. Those whose sight is normal will only observe a difference after I have added a cylin- drical lens to this apparatus, and thus made it astigmatical (Fig. 5). Fig. 4. Fig. 5.