region would be of little value. This is unfortunate, since a blue or blue- 

 green band is essential (in addition to a green spectral band) for detecting 

 water color differences of primary significance. The blue and blue-green 

 spectral region is also where the attenuation of light in clear water is 

 least, and greatest photo-optical depth penetration is possible. 



In the course of image enhancement work in our laboratory, numerous Gemini 

 and Apollo natural color film images of oceanographic subjects have been 

 color-separated by photo-optical means. It has been found that the blue- 

 sensitive layer in these films contains substantial information despite the 

 effect'', of the atmosphere. Examples are shown in Figures lA, B and 2A,B; 

 where blue and green separations made from typical images, taken from orbital 

 altitude, are compared. 



It is concluded that it is quite feasible to utilize a spectral band in the 

 460-500 ma region for remote sensing in oceanography; and if the many 

 important oceanographic phenomena associated with water color are to be 

 detected, it will be essential to record and couple this spectral band with 

 a green record. 



19-4 



