C41 delay developer > bleach

macrumpel · Feb 7, 2022

Hello

I am still in my learning curve for c41. I started finally to respect the standardized procedure with 38 degree C and continuous agitation in a 39 degrees water bath (new digibase 2.5l kit).
Of course my son coming in with some computer question, my bleach was not yet at temperature after 3:15 developer (after 2 min pre wash). Of course I poured it out but bleach was ready to pour in only 15 min later.
I had thin négatifs with some grain and inconsistencies in color on the scanner.
What would you expect from long delay between developer and bleach ?
I do not use a stop bath.
Thank you all and yes I order à lab water bath for preheat the chemicals.
Hubertus from France

brbo · Feb 7, 2022

Just pour the bleach (or stop) IMMEDIATELY after developer. Never mind the temperature. I mean, of course it's better that bleach is at the right temperature, but working temperature window for bleach is much wider than that of the developer. If for example, bleach was only at 30ºC at the time, you would simply extend the bleach time.

But in this unfortunate case, your negatives should be overdeveloped (and streaky), not underdeveloped. Maybe something else went wrong too (underexposure?)...

halfaman · Feb 7, 2022

You can also rinse with several tap water baths between CD and bleach if the wait is going to be a bit long.

foc · Feb 7, 2022

brbo said:
Just pour the bleach (or stop) IMMEDIATELY after developer. Never mind the temperature. I mean, of course it's better that bleach is at the right temperature, but working temperature window for bleach is much wider than that of the developer. If for example, bleach was only at 30ºC at the time, you would simply extend the bleach time.

But in this unfortunate case, your negatives should be overdeveloped (and streaky), not underdeveloped. Maybe something else went wrong too (underexposure?)...

+1

macrumpel · Feb 7, 2022

Thank you very much to reassure me in going on with the processus and mind a few degrees in bleach temperature. I might use a stop bath, but dont have acetic acid easily available. Citric acid might be used also?
Indeed, underexposure could be a problem, the film was quite old (Kodak Gold). But there were two rolls and both looking equal thin.

halfaman · Feb 7, 2022

macrumpel said:
Thank you very much to reassure me in going on with the processus and mind a few degrees in bleach temperature. I might use a stop bath, but dont have acetic acid easily available. Citric acid might be used also?
Indeed, underexposure could be a problem, the film was quite old (Kodak Gold). But there were two rolls and both looking equal thin.

PE adviced to avoid citric acid as stop for color processes. He didn't remember the reason because it was also an advice he recieved from someone at Kodak R&D. Acetic acid is very easy to purchase, it is usually available as a cleaning product in supermarkets at 8-10% dilutions and labelled like "vinegar for cleaning" o something like that.

Bronson Dugnutt · Feb 7, 2022

Delaying the blix / stop bath after pouring out the developer will lead to carry-over development and some of the image defects others have indicated; uneven development and/or severe color shifts, perhaps aggravated further by the age/condition of the film. Using tap water doesn't really work well as a color stop bath in my experience, but is probably better than nothing. (Tap water can be a gamble anyway; many municipal supplies are rife with chloramine or other adulterants, but that's another thread...)

I use a split bleach / fix step in all my color processing, so a stop bath is mandatory. A blix will have the same effect as a stop bath but an extra stop bath prior to blix will help preserve the life of the blix solution.

Acetic acid (white vinegar) is standard for C-41 and Sulfuric acid is standard for ECN-2. You'll get a lot of hand-waving around here about why or why not citric acid is appropriate for C-41. It may be fine for low volume home processing but cause unforeseen issues if using a replenishment line like those found in commercial labs. Some people even say the correct stop bath is needed to finalize the dye molecules in the emulsion... I guess we may never know.

brbo · Feb 7, 2022

Bronson Dugnutt said:
Acetic acid (white vinegar) is standard for C-41

Actually, standard C-41 doesn't use a stop (of any kind) between developer and bleach.

foc · Feb 7, 2022

brbo said:
Actually, standard C-41 doesn't use a stop (of any kind) between developer and bleach.

+1
and commercial C41 doesn't use it either.

Bronson Dugnutt · Feb 7, 2022

brbo said:
Actually, standard C-41 doesn't use a stop (of any kind) between developer and bleach.

You're being a bit obtuse with this statement, as C-41 blix is essentially a combination of stop bath, bleach, and fixer. A dedicated ferricyanide bleach requires additional steps.

https://www.photrio.com/forum/threads/c41-bleach-formula.12343/#post-171028

Photo Engineer said:
...
If someone tries to pass off to you a Ferricyanide bleach, remember that it is cost effective, but you need a wash and clearing bath after the color developer and before that type of bleach or you will cause a lot of stain, and you need to wash well before you go into the fix.

So, here goes:

Ammonium Ferric EDTA solution (50 - 60%) 200 ml
Ammonium Bromide 150 g
Disodium EDTA 10 g
Ammonium Sulfite 10 g

Dissolve in 500 ml water and bring to 1 liter. Adjust pH to 6.5 with 28% acetic acid.

...
PE

EDTA is an acetate complex and final pH adjustment is done with acetic acid as it is chemically compatible with the other reagents. Having used the same liter of neutral pH ferricyanide bleach for several years I can vouch for its effectiveness if used correctly.

foc · Feb 7, 2022

Bronson Dugnutt said:
You're being a bit obtuse with this statement, as C-41 blix is essentially a combination of stop bath, bleach, and fixer. A dedicated ferricyanide bleach requires additional steps.

Standard commercial C41 doesn't use a ferricyanide bleach.

halfaman · Feb 7, 2022

Also minilab processors has squeeze rollers between baths to minimize carry-over as much as possible.

mohmad khatab · Feb 8, 2022

macrumpel said:
Thank you very much to reassure me in going on with the processus and mind a few degrees in bleach temperature. I might use a stop bath, but dont have acetic acid easily available. Citric acid might be used also?
Indeed, underexposure could be a problem, the film was quite old (Kodak Gold). But there were two rolls and both looking equal thin.

Do not use citric acid in the color process.
A friend of mine used food vinegar at a concentration of 2% for two minutes with rapid stirring at room temperature, then a quick rinse after that, and the results were very impressive.

macrumpel · Feb 8, 2022

halfaman said:
Also minilab processors has squeeze rollers between baths to minimize carry-over as much as possible.

This is interesting. Industry standards go to perfection. But then the film goes directly into the next treatment chamber without pouring out and the next film follows already... Would be interesting to see!

mshchem · Feb 8, 2022

halfaman said:
Also minilab processors has squeeze rollers between baths to minimize carry-over as much as possible.

This is true. I don't use stop but a quick rinse is ok.

Bronson Dugnutt · Feb 8, 2022

C41 delay developer > bleach

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