Reciprocity Factor (Ilford)

Cameras, lenses, tripods..
Mick Fagan
Posts: 328
Joined: 24 Sep 2015, 21:20
Location: Melbourne

Re: Reciprocity Factor (Ilford)

Postby Mick Fagan » 12 Nov 2021, 12:13

Walter, you mentioning David Vestal brought back quite few memories of many magazine articles I somehow managed to read; usually in the local library as I couldn't afford American photographic magazines at the time.

Quite the print worker and I clearly remember a mammoth testing program he did on B&W papers and the major differences between graded paper and multigraded papers.

Well it may be raining all the way to Sydney, but I definitely know it is raining like crazy down here, flooded streets and trees down everywhere. I met up with three people yesterday and we discussed the recent big storms, one lost power for 6 days, the second power and gas for 9 days while the third lost power for almost 2 days. We also lost power, but we are fortunate enough to have house batteries and we weathered the storm unscathed.

Back to the testing, the Bergger Panchro 400 is looking good, but I don't think I'll use it, normal development D76 1:1 17 minutes at 20ºC, however FP4+ is looking really good with a half stop developer increase and using Ilford's reciprocity formula. This chart which is really a factor chart, leaves drawn charts for dead. So easy to use, providing one has a mobile phone calculator and uses the appropriate formula, you're in business.

Metered time of 5 seconds, corrected time of 7.598051.... I used 8 seconds and just for once I remembered to pack my Seiko stop watch which I picked up last century when the local primary school switched over to electronic stop watches for $2.00; mechanical marvel.

As for stand development, not really a fan of it. I had a brother who extolled the virtues of stand development in the 70's and he tried hard to get me to give it a go. I did and I don't think I've used it since.


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