The three chai'-acterlstlc vectors and the amounts of the vectors 



required to matc'i each sample are calculated from these data. 



Tlie film exposures can be determined in one of tv;o ways. If 



all the physical data are available^ v,'e can compute the film 



exposures directly. Lacking the physical data, vie can photograph 



the calibrating samples and derive the film, exposures by photo- 



gi"'aphic photometry as shov/n in Figure 8. The transf orm.ation 



bet'A'een the two coordinate system.s can then be estimated by 



multiple regression analysis. 



The transformation between color film exposure and the 



algae vector space is shovm in Equations 3. 



y-j_ = o.732^^*R + o.290i«-G + o.79^^'^-"-3 - 0.6980 



Yg = 3.^i-640-"-R + 2.4240->!-G - 3.6570*3 + 0.7389 (3) 



Y3 = -5.5420-R + 6.8730*0 + 6.36oo*B - 0.6430 



The algae curve shovm in Figure 1 and a curve computed from film 



exposures is shovm in Figure 9- The original curve is shov.n as 



a solid line, the reconstruction from film data as +. 



The transf orm.ation betv/een film exposures and daylight 

 vector space is shov/n in Equations 4. 



Y-|_ - -0.09?02-R - 2.7300*G + 3-0370*3 



Yg = l6.100*R - 19.360*0 + 6.6440*xi 



(^0 

 + 6.6440*B 



31-11 



