shorten.the exposure time. An independent test verified that a
shorter exposure on several points gave results consistent with the
120 second measurement. This indicates that the 120 second exposure
did not cause significant reciprocity failure. The film processing
procedure is outlined briefly in the printout with developing times
and temperatures recorded. The data from the measurement of the film
includes the step number, the exposure through that step, the density
on the developed film, and the associated amplitude transmission.
The computer tabulates several useful points from the data. The
exposure and transmission at the point of inflection are provided.
The best linear fit is determined by the slope and intercept of a line
tangent to the curve through the inflection point. Also, since most
phase holograms are exposed to OD 2.0, the appropriate exposure value
is provided. Finally, the printout provides the polynomial
coefficients for the transmission vs. exposure curve and its inverse
relationship along with the coefficient of correlation. The H & D
plot is found in Figure 6.3 for the AGFA 10E75 plates. The associated
transmission vs. exposure is plotted in Figure 6.4. The plot shows
the linear fit through the inflection point and the result of the 5th
order polynomial. Figures 6.5 through 6.7 are identical to Figures
6.2 through 6.4 except the results are for AGFA 8E75 plates.
Computer Linearization of Filter Response
The models presented here include a summation of terms
representing various powers or orders. The linear term or first order
represents the desired term where the transmission is linear with
exposure. If the linear term represents the signal and the higher
order terms represent noise, then the recording on the film is