----- Original Message -----
From: "Jason Russell" <jrussell@wishtv.com>
>
> Will the equation change with different types of film?
The equation is just a math model of the reciprocity correction curve, the
latter is just a graphic representation of the discrete values, either given
by manufactures (like the ones given by Polaroid for the film in question -
Polapan type 72) or obtained by us thru experimentation. Since each film
has its own reciprocity characteristics, each film would have its own
equation.
> Or do I just plug
> the indicated time into the equation to get a starting point? If it does
> change, which numbers will be different and how do I figure them out
All the coefficients change. You can find them by doing a Regression
analysis of the known reciprocity correction values, I use the Least Square
polynomial method, here is a hint on how to do that:
http://www.efunda.com/math/leastsquares/lstsqrmdcurve.cfm , for those of us
confused by the above, using a program like WinCurveFit
http://www.krs.com.au/wcf.html is "a good thing", that is what I used to
give you the answer BTW.
Guillermo
Received on Tue Oct 29 17:07:43 2002
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