Guillermo, The corrected time you gave me worked very well. Thank you!
However, I want to clarify one thing... Did you go to the Polaroid website to get the numbers to plug into the WinCurveFit program? Did you just pull the numbers from the displayed graph and plug them into the program and extend the curve? Is that how that works. Thanks again! Jason Russell WISH-TV Indianapolis, IN "If you go any faster we're gonna travel back through time." ----- Original Message ----- From: "Guillermo" <pen...@rogers.com> To: <pinhole-discussion@p at ???????> Sent: Tuesday, October 29, 2002 5:06 PM Subject: Re: [pinhole-discussion] Polaroid Reciprocity > > ----- Original Message ----- > From: "Jason Russell" <jruss...@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 > > > _______________________________________________ > Post to the list as PLAIN TEXT only - no HTML > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??????? > unsubscribe or change your account at > http://www.???????/discussion/ >
