Home developing question

[DIW35]

For many years I have been a 35mm shooter, but have recently taken up shooting medium format.

When it comes to home developing, many manufacturers list the film capacity of their fixr as so many rolls of 36 exposure 35 mm films. Is there a recognised or easy way to convert that to work out what the equivalent capacity is for 120 roll film?

I'm developing black and white film, though I don't think that should make any difference.

[Speed addicted]

Work out the surface area I suppose?

[Speed addicted]

Ok Google reckons that medium format has approx 4 times the surface area of 35mm, so a quarter of the shots before the fixer is depleted.
Probably.

[Simpo Two]

Speed addicted said:

Ok Google reckons that medium format has approx 4 times the surface area of 35mm, so a quarter of the shots before the fixer is depleted.

Of course, back in the days of film they'd have worked that out without forums or Google

[Speed addicted]

Simpo Two said:

Speed addicted said:

Ok Google reckons that medium format has approx 4 times the surface area of 35mm, so a quarter of the shots before the fixer is depleted.

Of course, back in the days of film they'd have worked that out without forums or Google

Back in the day they d have seen medium format film in real life!
I had no idea how big it was…

[DIW35]

Speed addicted said:

Ok Google reckons that medium format has approx 4 times the surface area of 35mm, so a quarter of the shots before the fixer is depleted.
Probably.

A 6x4.5 negative is about 2.8 times the area of a 35mm neg, but you only get 15 shots on a roll compared to 36. On that basis, there's not that much difference in the actual exposed area.

I think it's going to be a case of trial and error.

[fourfoldroot]

The life of the fixer is dependent on a few factors including storage and area of cleared negative . When I was an impecunious photography student, we would use it till it took double the time for the negatives to clear, compared to fresh fixer. This is from the instructions.

[Slipperman]

Until about 2008 I developed B&W films only, scanning them thereafter.
Previously did prints too until 2001

Went fully 'Digital' in 2008

If you already have a negative in Medium Format, measure it or and see how far it goes up inside the Developing Drum/Tank, and mark it.
Then fill the empty Drum/Tank with water to that mark.

Then tip that water back into measuring jug, then you'll have your quantity.

That's what I'd do anyway.

[DIW35]

Slipperman said:

Until about 2008 I developed B&W films only, scanning them thereafter.
Previously did prints too until 2001

Went fully 'Digital' in 2008

If you already have a negative in Medium Format, measure it or and see how far it goes up inside the Developing Drum/Tank, and mark it.
Then fill the empty Drum/Tank with water to that mark.

Then tip that water back into measuring jug, then you'll have your quantity.

That's what I'd do anyway.

I know what the volumes are for my developing tanks, what I was actually asking is what is the life of the fixer once you've started using it. I think fourfoldroot's notice above gives a good indication on how you can test if the fixer is still useable.

[Speed addicted]

In my industrial radiography past we would simply use the chemicals until developing and fixing took a noticeably longer time, then replace.

To be fair though they were 25 litre tanks and we weren’t paying for the chemicals.

Edited by Speed addicted on Wednesday 17th December 20:37

[Slipperman]

DIW35 said:

Slipperman said:

Until about 2008 I developed B&W films only, scanning them thereafter.
Previously did prints too until 2001

Went fully 'Digital' in 2008

If you already have a negative in Medium Format, measure it or and see how far it goes up inside the Developing Drum/Tank, and mark it.
Then fill the empty Drum/Tank with water to that mark.

Then tip that water back into measuring jug, then you'll have your quantity.

That's what I'd do anyway.

I know what the volumes are for my developing tanks, what I was actually asking is what is the life of the fixer once you've started using it. I think fourfoldroot's notice above gives a good indication on how you can test if the fixer is still useable.

Ahh ok, I misunderstood.

Assuming the ratio of fixer to water is consistent with 35mm, then I can't see why it would differ from 35mm?