Response to Alternative to Xtol

Off course there is an industry standard. They call it ISO and they even put in on the box. In fact the testing procedures are more or less a copy of the Deutsche Industrienorm (DIN). I do not think it a very good idea to say that this is only a "relative" number on the box. The test is standardize and testers all over the world use it and also publish their results. I must admit that the tests both of us run do not comply 100% to the ISO test, which is described in detail in the ISO regulations (film manufacuters use a transparent step wedge and a standardized exposure), but the results should be the same and also the ISO rating should be comparable. This can be seen when film speed is published by independent sources. Somehow I see then that my tests results are not bad after all, when someone performs tests under ISO conditions, such as with colour films and finds that almost all ISO 400 speed negative film are in fact much closer to ISO 200. When there is no standard, why do the manufacuters claim there is? And there are manufacuteres that put different speeds on the box. Efke for example says their film has ISO 50 (true ISO speed). In the box you will find a list of different developers and the speed they recommend you rate them, all of which are higher than the ISO rating. Why does Ilford and the rest not do this? Quick answer: Because it would not look good -- they feel -- on the marketplace. Honesty ist not always honoured by consumer. If you have the choice between two films, one advertised as 400, but has only ISO 200, the other one advertised as 200, and it has 200, which one would you buy if you look for an ISO 400 film? Also I have to repeat myself: Different developers do not affect film speed in a significant way. My perception is that the speed obviously is more or less determined by the film itself and that the developers only affect speed to a lesser extent.

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