VIGNETTING.
The method used for shading away the outer portions of a picture is termed vig netting, and was at one time practised very largely b all photographers ; so much so that pie es which included head and shoulders oily were generally called vignettes. The practice, however, has fallen into considerable disrepute amongst the better class of photographers, few of whom now treat their pictures in this way if it can be avoided. It is quite true-that vignetting may be made use of to produce a very pleasing result, where the subject is light, full of half tones, and the back ground light but in pleasing contrast. Vignetting was welcomed by the old school of photographers as a means of covering up the marginal defects of their portraits. Stains and marks were a little too fre quent on negatives, evidences of deterio ration in the plate showed first at its edges, whilst the lenses used were capable of covering the margins none too well, and for all these reasons photographers joyfully hailed any excuse for using only the inner portion of the image. While they kept to head-and-shoulder pictures, their clients had perhaps little to complain of ; but when they commenced to vignette three-quarter lengths, landscapes, views of houses, and even machinery, the public mind rose up against it. Vignetting, then. should be kept to suitable subjects. If vignetting is indulged in, the effort should be to obtain an effect similar to a sketch ; the idea being that in such pictures the figure is thus thrown forward prominently.
To obtain the best effects, a light back ground must be employed ; although, by a skilful arrangement of the vig nettes, it is possible to do much to soften a fairly dark one. A really dark back ground, however, cannot be successfully vignetted by any method hut the " India tint process." The on the other hand, must never be quite white, only. The glasses used are flashed either orange or red. The centre portion of the colouring matter is removed by treatment with hydrofluoric acid ; aiming to leave the margin as soft as possible in the process. The margins are, however, very and usually a tone deeper than the head. The choice of a suitable background for photographs is considered in another section, the principal point to bear in mind being that it should graduate darker towards the bottom.
hard at the best, and the results obtained with such glasses are generally crude and inartistic. Vignetting glasses are never used by any but inexperienced amateurs. Fig. 240 shows the " Iris " vignetter, which consists of a piece of vulcanised fibre large enough to cover the frame, and containing a. central hole rather larger than the largest desired vignette open ing. Around the edges of this are