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# Thread: Conversion from rolls of 35mm to 4x5

1. ## Conversion from rolls of 35mm to 4x5

What factor do you use to convert a developer's minimum requirements to develop a roll of 35mm film to equivalent 4x5 sheets?

My math says a roll of 35 equals about 2 1/2 sheets of 4x5.

Is there an accepted conversion?

Thanks,
Jim

2. 1 roll 35mm - 1roll 120 - 4 sheets 5x5 - 1 sheet 10x8 thats the basic rule of thumb

Think a contact sheet for a roll of 35mm is 10x8 then it's more logical

Ian

3. Jim,
Ian's right on... save a typo.

1 (36 exposure) roll of 35mm = 1 roll of 120 = 4 sheets of 4x5 = 1 sheet of 8x10.

4. Thanks folks. I still can't reconcile the numbers, but I'll accept the consensus.

Now I can get some developing done!

5. as was already pointed out, if you try to make a contact sheet of an entire roll of 35mm, it takes up about an 8x10 sheet of paper. Similarly, you can make a contact print of four sheets of 4x5 on that same 8x10 sheet of paper...so, roughly speaking, 1 roll of 35mm has about the same area as four sheets of 4x5 or one sheet of 8x10.

Makes sense I guess. I was using the estimated surface area of a roll of 35mm 36 exp based on the size of a frame and some leader to determine the conversion and came out with the lower ratio.

The film came out fine yesterday using the 1:4 number and saved me a lot of developer.

Thanks again everyone.

7. Originally Posted by Jim Cole
Thanks folks. I still can't reconcile the numbers, but I'll accept the consensus.

Now I can get some developing done!
Think of printing proof sheets. One roll of 35mm, one roll of 120, 4 sheets of 4x5, and one sheet of 8x10 all fit on one page. Does that help explain why they're the same in area?

8. Originally Posted by Jim Cole
Makes sense I guess. I was using the estimated surface area of a roll of 35mm 36 exp based on the size of a frame and some leader to determine the conversion and came out with the lower ratio.
You're leaving out the film edges and spaces between the frames, which are also coated with emulsion of course.

9. Originally Posted by Chazzy
Think of printing proof sheets. One roll of 35mm, one roll of 120, 4 sheets of 4x5, and one sheet of 8x10 all fit on one page. Does that help explain why they're the same in area?
Chazzy,

Exactly what Brad said previously, and it does make sense and now it will be easlier to remember. However, if you think about it, there is a lot of white space on an 8x10 proof sheet of 35mm images...nah...I won't go there.

David,

You're absolutely correct. I thought I added enough extra to compensate in my calculations, but evidently there is more non-image area than I thought. Guess I'd have to open an old 35mm cassette and measure the darn thing, but then I'd have to account for the sprocket holes!

Anyway, 1:4 works and thanks again to all who contributed.

10. There is actually a lot of black space on a 35 mm proof sheet. Any way, it's a rule of thumb for estimating developer capacity. One person's thumb may be larger than another's, and anyway, how do you account for different exposures, stuck shutters, or any of several other ways the required developer capacity may be greater or less than estimated? You don't. You have to figure the worst case will be if everything is nearly black. 1:4 is close enough for government work.

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