OSA's Digital Library

Journal of the Optical Society of America

Journal of the Optical Society of America

  • Vol. 54, Iss. 4 — Apr. 1, 1964
  • pp: 492–497

Study of the Mechanism of Sulfur Sensitization by a Development-Center Technique

H. E. SPENCER, L. E. BRADY, and J. F. HAMILTON  »View Author Affiliations

JOSA, Vol. 54, Issue 4, pp. 492-497 (1964)

View Full Text Article

Acrobat PDF (812 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



An investigation has been made of the distribution of development centers among the grains of a simple experimental emulsion and of the influence of sulfur sensitization on this distribution. The distribution of image centers among the grains which have not been deliberately chemically sensitized is not random, but shows instead a strong preference for only one center per grain, regardless of the intensity of the exposing light. For low-intensity exposure, the same emulsion after sulfur sensitization still shows only one development center per grain. At higher intensities, the number of development centers increases. The transition in the distribution of centers in the sensitized emulsion coincides with the onset of high-intensity, reciprocity-law failure. At very high intensity, the observed distribution agrees with the Poisson formula for a random distribution. Latensification with a gold solution, which eliminates high-intensity, reciprocity-law failure, does not affect the form of the speck distribution. This difference resulting from sulfur sensitization is most easily explained in terms of an increase in stability at the sites where latent-image centers form, e.g., an increase in electron trap depth.

Although the emulsion does not solarize, an examination of the development centers reveals that prolonged, low-intensity exposure of the sulfur-sensitized emulsion causes regression of all but one center per grain.

H. E. SPENCER, L. E. BRADY, and J. F. HAMILTON, "Study of the Mechanism of Sulfur Sensitization by a Development-Center Technique," J. Opt. Soc. Am. 54, 492-497 (1964)

Sort:  Author  |  Journal  |  Reset


  1. W. G. Lowe, J. E. Jones, and H. E. Roberts, in Fundamental Mechanisms of Photographic Sensitivity, edited by J. W. Mitchell (Butterworths Scientific Publications Ltd., London, 1951), p. 112.
  2. J. W. Mitchell, J. Phot. Sci. 9, 328 (1961).
  3. H. E. Spencer and R. E. Atwell, J. Opt. Soc. Am. 54, 498 (1964).
  4. W. Scheffer, Brit. J. Phot. 54, 116, 271 (1907).
  5. M. B. Hodgson, J. Franklin Inst. 184, 705 (1917).
  6. T.Svedberg, Phot. J. 62, 186, 310 (1922).
  7. F. C. Toy, Phil. Mag. 44, 352 (1922); ibid. 45, 715 (1923).
  8. W. Clark, Brit. J. Phot. 69, 462 (1922).
  9. H. Hoerlin and F. A. Hamm, J. Appl. Phys. 24, 1514 (1953).
  10. E. Klein, Z. Elektrochem. 62, 870 (1958); E. Klein and R. Matejec, Z. Elektrochem. 63, 883 (1959).
  11. G. Sprague, J. Appl. Phys. 32, 2410 (1961).
  12. An unfinished emulsion is one which has not undergone the finishing process by which the emulsion is chemically sensitized. The term unfinished emulsion is meant to imply the absence of any deliberate chemical sensitization.
  13. J. F. Hamilton and L. E. Brady, J. Appl. Phys. 30, 1893 (1959).
  14. F. A. Hamm and J. J. Comer, J. Appl. Phys. 24, 1495 (1953).
  15. E. S. Pearson and H. O. Hartley, Biometrika: Tables for Statisticians (Cambridge University Press, Cambridge, 1958), Vol. 1, p. 205.
  16. These arguments apply to grains with little or no tendency to form internal image centers. The observation has been made that, in certain similar emulsions with a small amount of developable internal centers in 10% to 15% of the grains, a small diminution of perhaps 10% to 15% of the maximum density occurs upon extensive exposure in excess of the exposure necessary to make all the grains developable.
  17. C. E. K. Mees, The Theory of the Photographic Process (The Macmillan Company, New York, 1954), revised edition, Chap. 7.

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited