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242 CINEMATOGRAPHIC ANNUAL
8. An explanation is offered for the excessive graininess which sometimes occurs with certain types of subjects. This is probably due to the nature of the subject which requires rendering large unbroken areas by positive densities which lie near the maximum graininess. The various remedies for this condition are discussed.
Crabtree29 attempted to parallel very closely practical motion picture conditions in his work and found little effect of exposure on graininess under such conditions. He found that matched prints from exposures at f 1 1 and f 3.5 on the same scene showed no appreciable difference in graininess. He found maximum graininess of the print dependent somewhat on the degree of development of the negative and recommended avoiding high gammas in development of negatives. In particular he recommended a borax developer as resulting in less graininess than other commercial developers. A. von Barsy32 spoke very highly of this borax formula for avoiding graininess in negatives.
The value of this type of developer appears to be in its slow developing action coupled with the solvent action of the sulphite upon silver bromide which permits the surface of the grain to be dissolved slightly thereby reducing the probability of development as clumps. If this is correct, other developing formulae, already cited, proposed to reduce the individual grain size, should be directlv applicable to the reduction of graininess of negatives. Steigmann33 suggested a pyro soda formula for avoidance of graininess. This is in accord with some of the earlier work showing that pyro soda developers produced somewhat less grain and graininess than others. Moyse and White34 suggested a somewhat different borax formula as being suitable for fine grain negative development. Carlton and Crabtree35 discussed the effect of variation of the constituents in a borax developer on the graininess producing properties of that developer.
It appears that pictures with a minimum appearance of graininess should be produced by —
(a) Use of a negative emulsion having a fine original silver halide grain.
(b) Use of adequate exposure but avoidance of over-exposure.
(c) Use of a developer designed to develop the film with a minimum of graininess such as a borax developer of the type indicated.
REFERENCES
1. L. A. Jones and N. Deisch, Brit. J. Phot., 1920. 67. 589-695. 706-709 or J. Frank. Inst., 1920, 190, 657.
2. A. 8 L. Lumiere and A. Seyewetz, Brit. J. Phot., 1904, 51, 630.
3. Wallace. Astrophys J.. 1904, 20, 113.
4. W. SehefFer, Brit. J. Phot., 1907. 54, 116. 272, 544
5. Hodgson, J. Frank. Inst , 19 17. 184, 705.
6. T. Svedberg, Zeits. Wiss. Phot., 1920. 20, 36-50.
7. G. Higson, Phot. J.. 1920. CO, 161.
8. E. P. Wightman and S. E. Sheppard. Brit. J. Phot.. 1921, 68. 169-172.
9. C. E. K. Mecs, J. Frank. Inst.. 1921. 191, 631-650.