FIGURE 5.
Double difference spectra, reflecting the spectral changes induced by an increase in dark adaptation time. In A, the spectrum was generated by a one-to-one subtraction of Fig. 4 C (20-min dark adaptation) from Fig. 4 A (2-h dark adaptation). In B, the spectrum was generated by a one-to-one subtraction of Fig. 2 C (20-min dark adaptation) from Fig. 2 A (2-h dark adaptation). C shows a control double difference spectrum constructed by subtracting one-half of the 2-h data set from the other half of the data set and dividing by a factor of 1.4. D shows a control spectrum constructed with data acquired before each actinic flash. On the y-axis, the tick marks are 1 × 10−4 absorbance units.