Archived posting to the Leica Users Group, 2011/06/08
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]And from the 1943 HP3 entry "(post 1960 the 200ASA emulsion was revised to 400ASA but there was no actual speed increase, it was in recognition that with better exposure determination methods at that time, there was no longer need for all film manufacturers to include an exposure safety margin. This 2x speed increase applied to all black&white films of all makes)." john - with a quiet day at work ________________________________________ I would guess 1960, in the 1938 (HP2) entry on http://www.photomemorabilia.co.uk/Ilford/Chronology.html it mentions "the film was rated at 125ASA (equivalent to a 250ASA emulsion after the 1960 'universal' speed rating revision" john ________________________________________ Both sites cite the change of HP3 and or HP4 from 200 to 400 without citing the exact date this happens. Mark This photography-related LUG email is a stub. You can help Rabopedia by expanding it. ____