Reprinted from APPLIED OPTICS, Vol, 8. page 2565, December 1969 

 Copyright 1969 by the Optical Society of America and reprinted by permission of the copyright owner 



A Photographic Means of Obtaining 

 Monochromatic Spectra of Marine Algae 



S. R. Baig and C. S. Yentsch 



Oeeanographic Center, Nova University, Fort Lauderdale, 

 Florida 33316. 

 Received 16 July 1969. 



There are many cases in which it is time-consuming or difficult 

 to measure routinely the visible absorption spectra of a large 

 ntimber of samples. Multivariate analysis of color photographs 

 of the samples provides a simple method by which it is possible 

 to reconstruct the spectra once the material of interest has been 

 spectrophdtometrically calibrated. It is then only necessary to 

 take a photograph and measure the density of the three dye 

 layers in the film with a three-color densitometer. From these 

 data the absorption spectrum can be generated. 



The original application of characteristic vector analysis to 

 photographic problems was made by Simonds.' He was able 

 to reconstruct any one of over 100 Hurter-Driffield curves 

 (density vs log exposure) using the mean curve of the samples and 

 four vectors and their corresponding scalar multipliers. The 

 mathematical technique is outlined and an example calculated 

 in his paper. 



2566 APPLIED OPTICS / Vol. 8, No. 12 / December 1959 



31-2 



