Response to Alternative to Xtol

I am surprised about the speed you get. A very recent test with HP5 plus showed that there is no way to get close to a true ISO 400. Even the ISO 320 are a little optimistic in many respects, since -- obviously due to the sensitation -- the film is problematic with green rendition. How do you evaluate your tests? which densitometer do you use? Which camera (how do you determine that your shutter is correct before testing)? If you read Ilford literature carefully you will notice some telling statements. They write that their speed ratings are most often not based on the ISO system, but on an evaluation of print quality! This says nothing else but that they sacrifice shadow rendition for film speed, which makes the film better to sell. When the first Deltas came to the market this was particularly obvious. Delta 400 had a true speed of only around ISO 100. This made it understandable that this film claimed to have "medium speed" characteristics. Off course I have not tested all films on the market, but I have run thorough tests on all films that I use on a regular basis, which includes -- among other things -- determining film speed and developing time for my specific paper grade. Occasionally I will include a test shot in my films to be sure that film characterstics do not change (they usually are very stable) and that my testing system is all right. A comparison with the test results of a friend also gives me some "safety" that I am not off. To sum up: I am fairly convinced that I can prove my statements about film speed with the test I made.

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