Does pushing film use up more developer?

NikonFE

Member
Joined
Jun 15, 2023
Messages
14
Location
USA
Format
35mm
Hello all, I am planning to develop a bunch of rolls with a C41 kit, but all the rolls will be pushed +1 stop. The kit is supposed to do 15 rolls normally, and pushing requires an increase in dev time from 3 mins to 4 mins 40 seconds. Does this mean the kit is really only good for about 10 rolls each pushed 1 stop? The math here being:

15 rolls at 3 mins each = 45 mins total dev time.

45 mins total dev time divided by 4 mins 40 seconds = 9.6 rolls.

But of course the reactions between the film and the developer do not proceed linearly! Of course the first 3 mins consume more reactants than the 1 min 40 seconds of the push.

Is there a good rule of thumb for this? And for the same issue with pulling film?

Thank you and I apologize if this issue has already been answered on this forum before.
 

koraks

Moderator
Moderator
Joined
Nov 29, 2018
Messages
22,696
Location
Europe
Format
Multi Format
Well, color developers are typically used in such a way that they come nowhere near the point of exhaustion. This means it doesn't really matter to begin with.

Moreover, there's a flaw in your reasoning, I'm afraid. If you push film, this generally is understood as underexposing it and then overdeveloping it to obtain the same gamma. This means that in the end, the total amount of silver halide that's being reduced doesn't differ all that much. It's ever so slightly less, in fact, because you cut off some shadow detail (but there wouldn't be much development going on there anyway).

So it's simply not an issue and can safely be ignored.

Things that do matter are e.g. the release of halides, particularly iodide, from the emulsion, which seriously interfere with the activity of the developer. But this is a concern mostly if you reuse developer without adequate replenishment (not a good idea to begin with) or stretch the capacity of the developer by processing lots of rolls at the same time in a tiny volume of developer (also not a good idea).
 
OP
OP

NikonFE

Member
Joined
Jun 15, 2023
Messages
14
Location
USA
Format
35mm
OK, I see. Your explanation clarified a lot for me! Thank you.
 

Sirius Glass

Subscriber
Joined
Jan 18, 2007
Messages
50,354
Location
Southern California
Format
Multi Format
One stop is well within the latitude of exposure, so develop normally. A number of APUGgersPhotrio members have posted test of C41 exposure and development with arrays of the film tested with different exposures.
 
OP
OP

NikonFE

Member
Joined
Jun 15, 2023
Messages
14
Location
USA
Format
35mm
Sirius Glass said:
One stop is well within the latitude of exposure, so develop normally. A number of APUGgersPhotrio members have posted test of C41 exposure and development with arrays of the film tested with different exposures.
Click to expand...

You are saying I should skip the extended dev time and just use the normal 3 mins?
 

miha

Member
Joined
Feb 15, 2007
Messages
2,959
Location
Slovenia
Format
Multi Format
@NikonFE, might be a typo on your end but since you wrote it down twice, let me correct you, normal C41 dev time is 3:15 not 3'
 
OP
OP

NikonFE

Member
Joined
Jun 15, 2023
Messages
14
Location
USA
Format
35mm
miha said:
@NikonFE, might be a typo on your end but since you wrote it down twice, let me correct you, normal C41 dev time is 3:15 not 3'
Click to expand...

I've been using the FPP ECN2/C41 kit, which I am pretty sure is 107 degrees F for 3 mins 0 seconds. I've just been following that.
 

MattKing

Moderator
Moderator
Joined
Apr 24, 2005
Messages
52,873
Location
Delta, BC Canada
Format
Medium Format
NikonFE said:
I've been using the FPP ECN2/C41 kit, which I am pretty sure is 107 degrees F for 3 mins 0 seconds. I've just been following that.
Click to expand...

That is a higher than normal temperature.
And a shorter than normal time.
 

koraks

Moderator
Moderator
Joined
Nov 29, 2018
Messages
22,696
Location
Europe
Format
Multi Format
NikonFE said:
I've been using the FPP ECN2/C41 kit,
Click to expand...

I think that's a bit of an oddball kit. For one thing, as noted, the time and temperature are off-standard. I wouldn't lose too much sleep over that. What's more 'challenging' is that it's marketed as a combined ECN2 and C41 kit, but ECN2 really is a CD3-based developer working at a significantly higher pH than C41, which is CD4-based. While you'll certainly get a color image if you process ECN2 film in C41 developer and vice versa (the former I've done several times), it's in my experience not optimal in terms of color balance and crossover, and there are also doubts about dye stability with this kind of cross-processing.

Again, you will get images alright. Just some caveats involved.
 
OP
OP

NikonFE

Member
Joined
Jun 15, 2023
Messages
14
Location
USA
Format
35mm

OK, that makes sense. What kit would you recommend for C41? I wanted a kit with a separate bleach / fixer stage because I understand that might be archival or better in some way. The Cinestill C41 kit that many recommend is only 2 bath.
 

koraks

Moderator
Moderator
Joined
Nov 29, 2018
Messages
22,696
Location
Europe
Format
Multi Format
Isn't the FPP kit also the one that uses a ferricyanide bleach? Is the bleach yellow instead of brown? Ferricyanide will bleach color films fine and it's one of the recommended bleaches for ECN2 film, but it was never specifically recommended for C41 film, and likely not tested much with it to the best of my knowledge. There are doubts about dye stability if such a bleach is used with C41 film. I'm pretty optimistic the negatives will last a good while, but no guarantees.

I myself stick to Fuji chemistry because it has or used to be relatively cheap here in Europe on a per liter basis. In the US I think you can still get Kodak Ektacolor chemistry, which is just as good.

A good blix may work quite well, but opinions vary a bit on the slight amount of retained silver there may or may not be left. If you want to do 'best in class', get (or assemble) a kit with a modern PDTA bleach or otherwise a somewhat slower but also qualitatively good EDTA bleach. Check the MSDS for a product to get a feeling for what's in it. Either PDTA or EDTA will be on there if it's actually part of it.
 

MattKing

Moderator
Moderator
Joined
Apr 24, 2005
Messages
52,873
Location
Delta, BC Canada
Format
Medium Format

miha

Member
Joined
Feb 15, 2007
Messages
2,959
Location
Slovenia
Format
Multi Format
NikonFE said:
OK, that makes sense. What kit would you recommend for C41? I wanted a kit with a separate bleach / fixer stage because I understand that might be archival or better in some way. The Cinestill C41 kit that many recommend is only 2 bath.
Click to expand...
Bellini C41 Kit comes with a separate bleach / fix. I'm using it with great success.
 
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…