Abstract

A computer program was developed to process photographically recorded spectra for absolute intensity. Test and calibration films are subjected to densitometric scans that provide digitally recorded densities on magnetic tapes. The nonlinear calibration data are fitted by least-squares cubic polynomials to yield a good approximation to the monochromatic H&D curves for commonly used emulsions (2475 recording film, Royal-X, Tri-X, 4-X). Several test cases were made. Results of these cases show that the machine processed absolute intensities are accurate to within 15%. Arbitrarily raising the sensitivity threshold by 0.1 density units above gross fog yields cubic polynomial fits to the H&D curves that are radiometrically accurate within 10%. In addition, curves of gamma vs wavelength for 2475, Tri-X, and 4-X emulsions were made. These data show slight evidence of the photographic Purkinje effect in the 2475 emulsion.

© 1967 Optical Society of America

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References

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  1. R. C. Jones, J. Opt. Soc. Am. 51, 1159 (1961).
    [CrossRef]
  2. H. J. Zweig, O. C. Higgins, D. L. MacAdam, J. Opt. Soc. Am. 48, 926 (1958).
    [CrossRef]
  3. G. R. Harrison, R. C. Lord, J. R. Loofbourow, Practical Spectroscopy (Prentice-Hall, New York, 1948), Chap. 13.
  4. A. Guttman, Appl. Opt. 4, 91 (1965).
    [CrossRef]
  5. C. E. Kenneth Mees, The Theory of the Photographic Process (Macmillan Co., New York, 1954), revised edition.
  6. J. C. DeVos, Physica 20, 690 (1954).
    [CrossRef]
  7. F. E. Ross, Astrophys. J. 52, 86 (1920).
    [CrossRef]
  8. W. G. Planet, Appl. Opt. 3, 309 (1964).
    [CrossRef]

1965

1964

1961

1958

1954

J. C. DeVos, Physica 20, 690 (1954).
[CrossRef]

1920

F. E. Ross, Astrophys. J. 52, 86 (1920).
[CrossRef]

DeVos, J. C.

J. C. DeVos, Physica 20, 690 (1954).
[CrossRef]

Guttman, A.

Harrison, G. R.

G. R. Harrison, R. C. Lord, J. R. Loofbourow, Practical Spectroscopy (Prentice-Hall, New York, 1948), Chap. 13.

Higgins, O. C.

Jones, R. C.

Kenneth Mees, C. E.

C. E. Kenneth Mees, The Theory of the Photographic Process (Macmillan Co., New York, 1954), revised edition.

Loofbourow, J. R.

G. R. Harrison, R. C. Lord, J. R. Loofbourow, Practical Spectroscopy (Prentice-Hall, New York, 1948), Chap. 13.

Lord, R. C.

G. R. Harrison, R. C. Lord, J. R. Loofbourow, Practical Spectroscopy (Prentice-Hall, New York, 1948), Chap. 13.

MacAdam, D. L.

Planet, W. G.

Ross, F. E.

F. E. Ross, Astrophys. J. 52, 86 (1920).
[CrossRef]

Zweig, H. J.

Appl. Opt.

Astrophys. J.

F. E. Ross, Astrophys. J. 52, 86 (1920).
[CrossRef]

J. Opt. Soc. Am.

Physica

J. C. DeVos, Physica 20, 690 (1954).
[CrossRef]

Other

G. R. Harrison, R. C. Lord, J. R. Loofbourow, Practical Spectroscopy (Prentice-Hall, New York, 1948), Chap. 13.

C. E. Kenneth Mees, The Theory of the Photographic Process (Macmillan Co., New York, 1954), revised edition.

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Figures (5)

Fig. 1
Fig. 1

Typical re-entry emission spectrum showing spatially resolved atomic line radiation (Case III).

Fig. 2
Fig. 2

Re-entry spectrogram showing nearly uniform smear resulting from image motion during exposure (Case I). Such frames yield spatially integrated radiation spectra.

Fig. 3
Fig. 3

Representative outputs of machine processed monochromatic H&D curves at four wavelengths. The cubic polynomial functions are shown along with the calibration data input points. The plots were made on the Stromberg-Carlson 4020 plotter. The dimensions of Iλ(S) are W cm−2μ−1 sr−1. ● Raw data points. 2475 film developed in D 19 for 4 min, 30 sec at 22°C. 31 msec exposure time. —least-square computer fit.

Fig. 4
Fig. 4

Specular gamma vs wavelength for Kodak 2475 recording film derived from computer processed calibration curves (film developed in D19 for 6 min at 20°C).

Fig. 5
Fig. 5

Specular gamma vs wavelength for Tri-X negative film derived from computer processed calibration curves (film developed in DK50 for 6 min at 20°C).

Tables (2)

Tables Icon

Table I Analytical Functions Tested to Obtain a Good Fit to the H&D Curve at 5600 Å (Panchromatic Emulsion)

Tables Icon

Table II Standard Deviation of Iλ from the Polynomial Curves for Calibration Film in the 4000-Å to 6700-Å Wavelength Range

Equations (7)

Equations on this page are rendered with MathJax. Learn more.

I λ = N λ w τ c τ n t c / F c t t .
I λ = d J λ / d y ( τ a / R sin Ψ ) ,
J λ = ( R 2 Δ y / τ a F ) I λ ,
J λ = R 2 Δ y τ a F n i = 1 n I λ i ,
d J λ / d y = ( R sin Ψ / τ a ) I λ .
log I λ = A 0 ( λ ) + A 1 ( λ ) D + A 2 ( λ ) D 2 + A 3 ( λ ) D 3 ,
λ 1 λ J λ d λ .

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