Archived posting to the Leica Users Group, 1998/11/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Ron, If you have all the necessary equipment then you can be really scientific about it, like Erwin. If not, than the only method I can think of is to take some shots of a grey card, first at the indicated meter reading, then bracket in both directions in 1/3 or 1/2 stop increments. Develop the film. Then print a contact sheet with an exposure such that the perforated edges of the film are black on the print. Take your print and compare with the actual grey card to see which exposure matches closest. If you shot nominal 100 speed film but the closest matching shot is one where you overexposed by 1 stop, then your effective film speed is 50. Of course, what you are really testing here is your entire process, end-to-end: exposure, negative development, exposure in the enlarger, paper development. So the effective film speed you arrive at will only work for you and only so long as you keep the other process elements consistent. Nathan Ron & Beelian Miller wrote: > How does one test a film for its effective speed. Erwin has informed us > test results for some film, but I'd like an idea how to go through it > once so I know how to do it for other films? How would you conduct such > a test? - -- Nathan Wajsman Overijse, Belgium Photography page: http://members.tripod.com/~belgiangator/index.html Motorcycle page: http://www.geocities.com/motorcity/downs/1704/index.html