Film developing slide ruler

[smithdoor]

Here is one way of getting the developing time works great
A simple slide ruler for developing

Dave

[Kirk Gittings]

It looks like a slide rule version of the old Kodak dial thingy that came in the darkroom data guide book. With that a film had a guide number which determined its standard developing guide at 68 degrees and you used the dial to to dermine times at other temperatures + and - development etc. It wasn't precise but it worked and I used one for years figuring out my own guide numbers non Kodak and newer Kodak films.

[smithdoor]

It works great all you need is the time and temperature an 68F/20C of the film and developer slide the ruler to that location. Then just take the temperature of your developer and find on the slide ruler and there is the time you need for your film. The other is the numbers are larger no need for glass.

Yes I too have use the Kodak wheel works great too. I have not since made for over 30 years

Dave

[Cor]

Or use this (http://www.ilfordphoto.com/applications/page.asp?n=87) (bottom page) less neat but it works, have been using it for years..

Best,

Cor

[bigdog]

It looks like a slide rule version of the old Kodak dial thingy that came in the darkroom data guide book. With that a film had a guide number which determined its standard developing guide at 68 degrees and you used the dial to to dermine times at other temperatures + and - development etc. It wasn't precise but it worked and I used one for years figuring out my own guide numbers non Kodak and newer Kodak films.

I had forgotten that tool. but I used it for years, too. (... and still have it) Having evolved to always processing at the same temperature has eliminated the need.