Date this HP3
Can someone date this can of HP3 and the original speed? And any developing times for it? I assume it's a 125 version?
I'm looking for original developing times.
I want to treat it with halogen gas, bracket around the original speed and use an original developing time as an experiment.
By fortunate coincidence I dug out some information Ilford sent me a few years ago to answer another question on the forum about HP4. I still have it in front of me.
It tells me that HP3 was introduced in 1941 and it's replacement, HP4, was introduced in 1960.
The speed was 400 ASA (allowing for the fact that speed was calculated a bit differently in those days).
I've got some times for ID-11 and Microphen, but these are for 35mm , not sure if they apply to cine film?
HP3 400 ASA 35 mm:
ID-11 Normal contrast 9 mins. High Contrast 15:00 mins.
Microphen Normal contrast 7 mins. High Contrast 13:00 mins.
The first release 125, then 200 then 400 in HP3 iirc. But that's as much as a I have.
According to http://www.photomemorabilia.co.uk/Il...hronology.html
"Ilford HP3 Roll & 35mm Film first appeared. Initially 125ASA (250ASA post-1960). Around 1952-53 it became 200ASA (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)."
So it would be 250 or 400 I guess in todays terms.
I guess I'll just have to test with those starting times given.. convert them to Xtol perhaps.
I want to do a before and after test of the treatment and evaluate a useable speed.
I also did just find this - http://www.vurt.co.uk/2009/04/02/ilf...ic-found-film/
Last edited by Athiril; 09-16-2011 at 08:55 AM. Click to view previous post history.