All the means for success which the painter possesses are also available to the decorator; however, the latter may utilize some of the illusions of line, form, irradiation, etc., which the architect encounters. The decorator's field may be considered to include almost all of the painter's and much of the architect's. This being the case, little space will be given to this phase of the subject because painting and architecture are separately treated. The decorator should begin to realize more fully the great potentiality of lighting in creating moods or in giving expression to an interior. The psychology of light and the use of lighting as a mode of expression have barely been drawn upon by the decorator. Lighting has already been discussed so it will be passed by at this point. The practice of hanging pictures on walls which are brilliantly colored is open to criticism. There are galleries in existence where paintings are hung on brilliant green or rose walls. The changes in the appearance of the object due to these highly colored environments are easily demonstrated by viewing a piece of white paper pinned upon the wall. On the green wall, the white paper appears pinkish; on the rose wall, it appears bluish or greenish. A portrait or a picture in which there are areas of white or delicate tints is subject to considerable distortions in the appearance of its colors. Similarly, if a woman must have a colored background, it is well to choose one which will induce the more desirable tints in her appearance. The designer of gowns certainly must recognize these illusions of color which may be desirable or undesirable. The lighting of a picture has already been mentioned, but the discussion was confined solely to distribution of light. The quality of the light (its spectral character) may have an enormous influence upon the painting. In fact with the same painting many illusions may be produced by lighting. In general, paintings are painted in daylight and they are not the same in appearance under ordinary artificial light. For this reason the artist is usually entitled to the preservation of the illusion as he completed it. By using artificial daylight which has been available for some years, the painting appears as the artist gave it his last touch. Of course, it is quite legitimate to vary the quality of light in case the owner desires to do so, but the purpose here is to emphasize the fact that the quality of light is a powerful influence upon the appearance of the painting. The influence is not generally enough recognized and its magnitude is appreciated by relatively few persons.