Abstract

The d-log t curves of typical fast, medium, and slow emulsions when coated with oils fluorescing in the blue, near ultraviolet, and far ultraviolet respectively, have been studied in the region 900 to 5000 Angstroms by means of a vacuum spectrograph designed especially for photographic photometry, together with ordinary quartz spectrographs. The reciprocity and intermittency failures of the same emulsions, unoiled and when coated with the three oils, have been studied in the range 2300–5000A. The absorption and fluoresence spectra of the oils were also studied in the same range. It was found that the contrast obtained with oil coated plates is constant throughout that part of the spectrum in which the oil absorbs all of the incident light, and is equal to the contrast of the unoiled emulsion near the wave length of maximum intensity of fluorescence of the oil. As the oils studied absorb completely from their respective long wave limits down to at least 900A, the contrast obtained in the Schumann region was constant for a given oil-emulsion combination. This property greatly simplifies photographic photometry in the Schumann region, and enables one to assume the reciprocity law throughout that region when oil-emulsion combinations are used which have been found to obey the reciprocity law at the fluorescence maxima. Most of the secondary problems of photographic photometry are thus transferred from the difficult Schumann region to the near ultraviolet or visible where they can be more readily attacked. A device for varying intensities in the Schumann region is described, which is easily calibrated by means of the reciprocity law after the latter has been tested. A number of suggestions are made by which the use of fluorescent materials can be expected to simplify certain other problems of photometry.

© 1930 Optical Society of America

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References

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  1. P. A. Leighton and G. R. Harrison, Proc. Am. Phys. Soc., Phys. Rev.,  35, p. 134; 1930.
  2. G. R. Harrison, J.O.S.A. & R.S.I.,  19, p. 277; 1929.
  3. Duclaux and Jeantet, Jour. de. Phys. et Rad.,  2, p. 154; 1921.
  4. T. Lyman, Nature,  11, p. 113; 1922.
  5. G. R. Harrison, J.O.S.A. & R.S.I.,  11, p. 113; 1925, and J.O.S.A. & R.S.I. 11, p. 341; 1925.
    [CrossRef]
  6. P. R. Gleason, Proc. Nat. Acad. Sci.,  15, p. 551; 1929.
    [CrossRef]
  7. P. H. Helmick, J.O.S.A. & R.S.I.,  9, p. 521; 1924, and others.
    [CrossRef]
  8. Gleason, loc. cit.
  9. v. G. R. Harrison, J.O.S.A. & R.S.I.,  19, p. 287; 1929.
    [CrossRef]
  10. T. Lyman, Spectroscopy of the Extreme Ultraviolet, 2nd Ed., Longmans Green, 1928.
  11. G. R. Harrison, J.O.S.A. & R.S.I.,  11, p. 113; 1925, and J.O.S.A. & R.S.I. 11, p. 341; 1925.
    [CrossRef]
  12. W. T. Anderson and L. F. Bird, Phys. Rev. 32, p. 293; 1928.
    [CrossRef]
  13. C. E. Hesthal and G. R. Harrison, Bull. Amer. Phys. Soc., Berkeley Meeting, June, 1929. G. R. Harrison, J.O.S.A. & R.S.I.,  19, 302; 1929.
  14. G. R. Harrison, J.O.S.A. & R.S.I.,  18, p. 492; 1929.
    [CrossRef]
  15. C. E. Weinland, J.O.S.A. & R.S.I.,  15, p. 337; 1927, and J.O.S.A. & R.S.I. 16, p. 295; 1928.
    [CrossRef]
  16. G. R. Harrison, J.O.S.A. & R.S.I.,  17, p. 394; 1928.

1930 (1)

P. A. Leighton and G. R. Harrison, Proc. Am. Phys. Soc., Phys. Rev.,  35, p. 134; 1930.

1929 (5)

G. R. Harrison, J.O.S.A. & R.S.I.,  19, p. 277; 1929.

P. R. Gleason, Proc. Nat. Acad. Sci.,  15, p. 551; 1929.
[CrossRef]

v. G. R. Harrison, J.O.S.A. & R.S.I.,  19, p. 287; 1929.
[CrossRef]

C. E. Hesthal and G. R. Harrison, Bull. Amer. Phys. Soc., Berkeley Meeting, June, 1929. G. R. Harrison, J.O.S.A. & R.S.I.,  19, 302; 1929.

G. R. Harrison, J.O.S.A. & R.S.I.,  18, p. 492; 1929.
[CrossRef]

1928 (2)

W. T. Anderson and L. F. Bird, Phys. Rev. 32, p. 293; 1928.
[CrossRef]

G. R. Harrison, J.O.S.A. & R.S.I.,  17, p. 394; 1928.

1927 (1)

C. E. Weinland, J.O.S.A. & R.S.I.,  15, p. 337; 1927, and J.O.S.A. & R.S.I. 16, p. 295; 1928.
[CrossRef]

1925 (2)

G. R. Harrison, J.O.S.A. & R.S.I.,  11, p. 113; 1925, and J.O.S.A. & R.S.I. 11, p. 341; 1925.
[CrossRef]

G. R. Harrison, J.O.S.A. & R.S.I.,  11, p. 113; 1925, and J.O.S.A. & R.S.I. 11, p. 341; 1925.
[CrossRef]

1924 (1)

P. H. Helmick, J.O.S.A. & R.S.I.,  9, p. 521; 1924, and others.
[CrossRef]

1922 (1)

T. Lyman, Nature,  11, p. 113; 1922.

1921 (1)

Duclaux and Jeantet, Jour. de. Phys. et Rad.,  2, p. 154; 1921.

Anderson, W. T.

W. T. Anderson and L. F. Bird, Phys. Rev. 32, p. 293; 1928.
[CrossRef]

Bird, L. F.

W. T. Anderson and L. F. Bird, Phys. Rev. 32, p. 293; 1928.
[CrossRef]

Duclaux,

Duclaux and Jeantet, Jour. de. Phys. et Rad.,  2, p. 154; 1921.

Gleason,

Gleason, loc. cit.

Gleason, P. R.

P. R. Gleason, Proc. Nat. Acad. Sci.,  15, p. 551; 1929.
[CrossRef]

Harrison, G. R.

P. A. Leighton and G. R. Harrison, Proc. Am. Phys. Soc., Phys. Rev.,  35, p. 134; 1930.

G. R. Harrison, J.O.S.A. & R.S.I.,  19, p. 277; 1929.

v. G. R. Harrison, J.O.S.A. & R.S.I.,  19, p. 287; 1929.
[CrossRef]

C. E. Hesthal and G. R. Harrison, Bull. Amer. Phys. Soc., Berkeley Meeting, June, 1929. G. R. Harrison, J.O.S.A. & R.S.I.,  19, 302; 1929.

G. R. Harrison, J.O.S.A. & R.S.I.,  18, p. 492; 1929.
[CrossRef]

G. R. Harrison, J.O.S.A. & R.S.I.,  17, p. 394; 1928.

G. R. Harrison, J.O.S.A. & R.S.I.,  11, p. 113; 1925, and J.O.S.A. & R.S.I. 11, p. 341; 1925.
[CrossRef]

G. R. Harrison, J.O.S.A. & R.S.I.,  11, p. 113; 1925, and J.O.S.A. & R.S.I. 11, p. 341; 1925.
[CrossRef]

Helmick, P. H.

P. H. Helmick, J.O.S.A. & R.S.I.,  9, p. 521; 1924, and others.
[CrossRef]

Hesthal, C. E.

C. E. Hesthal and G. R. Harrison, Bull. Amer. Phys. Soc., Berkeley Meeting, June, 1929. G. R. Harrison, J.O.S.A. & R.S.I.,  19, 302; 1929.

Jeantet,

Duclaux and Jeantet, Jour. de. Phys. et Rad.,  2, p. 154; 1921.

Leighton, P. A.

P. A. Leighton and G. R. Harrison, Proc. Am. Phys. Soc., Phys. Rev.,  35, p. 134; 1930.

Lyman, T.

T. Lyman, Nature,  11, p. 113; 1922.

T. Lyman, Spectroscopy of the Extreme Ultraviolet, 2nd Ed., Longmans Green, 1928.

Weinland, C. E.

C. E. Weinland, J.O.S.A. & R.S.I.,  15, p. 337; 1927, and J.O.S.A. & R.S.I. 16, p. 295; 1928.
[CrossRef]

Bull. Amer. Phys. Soc., Berkeley Meeting (1)

C. E. Hesthal and G. R. Harrison, Bull. Amer. Phys. Soc., Berkeley Meeting, June, 1929. G. R. Harrison, J.O.S.A. & R.S.I.,  19, 302; 1929.

J.O.S.A. & R.S.I. (8)

G. R. Harrison, J.O.S.A. & R.S.I.,  18, p. 492; 1929.
[CrossRef]

C. E. Weinland, J.O.S.A. & R.S.I.,  15, p. 337; 1927, and J.O.S.A. & R.S.I. 16, p. 295; 1928.
[CrossRef]

G. R. Harrison, J.O.S.A. & R.S.I.,  17, p. 394; 1928.

G. R. Harrison, J.O.S.A. & R.S.I.,  11, p. 113; 1925, and J.O.S.A. & R.S.I. 11, p. 341; 1925.
[CrossRef]

G. R. Harrison, J.O.S.A. & R.S.I.,  19, p. 277; 1929.

G. R. Harrison, J.O.S.A. & R.S.I.,  11, p. 113; 1925, and J.O.S.A. & R.S.I. 11, p. 341; 1925.
[CrossRef]

P. H. Helmick, J.O.S.A. & R.S.I.,  9, p. 521; 1924, and others.
[CrossRef]

v. G. R. Harrison, J.O.S.A. & R.S.I.,  19, p. 287; 1929.
[CrossRef]

Jour. de. Phys. et Rad. (1)

Duclaux and Jeantet, Jour. de. Phys. et Rad.,  2, p. 154; 1921.

Nature (1)

T. Lyman, Nature,  11, p. 113; 1922.

Phys. Rev. (1)

W. T. Anderson and L. F. Bird, Phys. Rev. 32, p. 293; 1928.
[CrossRef]

Proc. Am. Phys. Soc., Phys. Rev. (1)

P. A. Leighton and G. R. Harrison, Proc. Am. Phys. Soc., Phys. Rev.,  35, p. 134; 1930.

Proc. Nat. Acad. Sci. (1)

P. R. Gleason, Proc. Nat. Acad. Sci.,  15, p. 551; 1929.
[CrossRef]

Other (2)

T. Lyman, Spectroscopy of the Extreme Ultraviolet, 2nd Ed., Longmans Green, 1928.

Gleason, loc. cit.

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Figures (7)

Fig. 1
Fig. 1

Sketch of the end-on discharge tube, designed for simplicity of construction. The discharge takes place in the tube marked 3, which is a straight tube of Pyrex of 8 mm internal diameter. All joints marked 1 are of sealing wax. Electrodes 4, of steel, and 6, of brass, are internally water-cooled, and electrode 2 can be similarly cooled if necessary. The shutter is marked 5. The vacuum spectrograph slit is at 6.

Fig. 2
Fig. 2

Curves showing the absorption of light in the range 5500–2000A by, (1) Motoreze heavy oil, (2) Cenco pump oil #11021, (3) Clear paraffin oil; together with the fluorescence spectra of the same three oils in (a), (b), and (c) respectively, when exposed to the quartz mercury arc spectrum. The fluorescence maxima have been set arbitrarily to the same value for the different oils. λF represents the wave length of maximum intensity of fluorescence, while λA represents the longest wave length below which all light is absorbed in a thin layer. Total extinction extends at least as far down as 900A for all three oils.

Fig. 3
Fig. 3

Reproduction of a typical film taken to obtain the d-log t curves of Eastman Par-speed film in the range 1000–3000A when coated with oil #2. The spectrum is that of the hydrogen discharge at 0.1 mm pressure. In most pictures of this kind an irregular order of exposure times was used to eliminate non-variable errors due to oil flow.

Fig. 4
Fig. 4

Typical d-log t curves obtained for Eastman Par-speed film which was coated with Oil #2, showing the uniformity of contrast in the range 1000–2700A, and the beginning of a in contrast as the wave length increases.

Fig. 5
Fig. 5

Curves showing the relation of contrast to wave length for the unoiled Cramer Contrast Process Plate, and for the same plate when coated with Oils #1, #2, and #3 respectively. By comparing these curves with those of Fig. 2, one observes the constancy of contrast at wave lengths up to λA, the dip in the curve due to partial absorption and partial transmission of the incident light, and the equality of contrast for the coated and uncoated emulsions at wave lengths above where the absorption begins. The contrast of the oiled emulsion below λA is also seen to be the same as that of the uncoated emulsion at λF.

Fig. 6
Fig. 6

Calibration curves for three different screw settings of the intensity varying flap in front of the grating. These were obtained by using emulsions coated with fluorescent oils which were found to obey the reciprocity law at λF, and assuming the reciprocity relation in the Schumann region.

Fig. 7
Fig. 7

Curves illustrating qualitatively the different relative sensitivities of an uncoated emulsion and of the same emulsion when coated with Oils #2 and #3. No data on actual sensitivity is obtainable at these wave lengths until thermoelectric measurements have been made of true intensities.