There was a simple one, I think it was on darkroomagic.com, that showed a couple films and then a column for conventional films. I've used that with success, it even shows the approximate effects on contrast, as in N+x. I think it was Ralph Lambrecht's site. The site is no longer, it would appear.
I found a great formula that works everytime, not sure if anyone else has posted it yet but here goes: 1.7 multiplied by metered time
plus .12 multiplied by metered time squared= corrected time, this formula works like a charm for me
"WOW! Now thats a big camera. By the way, how many megapixels is that thing?"
How does one post excel spreadsheets (.xsl files). I have a S.S. that was based on some formula that I read about on APUG. It gives me good results.
George
As StoneNYC says - forget it. Just get my App! :-)
I wish this discussion had been around when I started developing Reciprocity Timer 3 years ago.
This is the formula my app uses for Delta 100 and for HP5+
e = (0.51 * (m^1.62)) + m
where e is actual exposure and m is measured.
This is based on the Gainer/Bond Method as outlined in the article linked in the first page.
This yields times very close to Ilford's official charts.
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