Dignan NCF-41 Divided Color Negative Developer

I found that same method (2batch color developer) described in patent US3869288 by Leopold Godowsky in 1973

Hi there,
I'm looking at this recipe to use in a Rondinax 60 but am struggling to find sodium bisulphite. Can I use a slightly reduced quantity of Sodium Metabisulphite as an alternative?

According to rudeofus Sodium Metabisulphite is interchangeable with Sodium Bisulphite. He referred me to this archived web page
Thanks rudeofus

Hi Adrain

We are interested in how you get on with this.

And Id note PE's caution about the layers/diffusion, you are going to have to white balance in PS.

The HSA can be an active developer chemical as it is (or a close analogue) at the bottom of the list of development chemicals in complexity.

But it is omitted from the cine negative film developer, which does use CD3 as well.

Good luck

Noel

I've got nearly all the gear for this, I'll give it a bash tomorrow (if there's any light to take some snaps by).

I think you can substitute Sodium carbonate (which is what I have) for Potassium carbonate at ~0.8 by weight - is that about right?

I would not add HAS or anything else to this formula before testing it first. Both HAs and KI will change the color balance and there are already enough variables involved without adding any more. Many years ago I processed Agfachrome at home from the formulas published in the Dignan Newsletter. It took quite a bit of testing to get the amounts of two of the chemicals adjusted to get the right color balance. The resulting slides were beautiful but the initial effort was rather high. Anyone expecting to mix up this formula and immediately start cranking out C-41 negatives is in for an unpleasant surprise. As with any two bath developer the formulation is film specific. This usually means tweeking things for each film used. Unless a person's interest is for experiment I would suggest staying with the standard C-41 process.

FWIW (not much, I suspect) I cranked out a roll of C-41 negatives with this formula today, just for the fun of it., using AgfaVista200 (the UK colour experimenter's film of choice at £1/roll)

It wasn't clear to me whether the stated 75° temperature was for mixing or processing, so I aimed for a processing temperature of 100°.
Agitation isn't specified either so I gave gentle agitation, every 15s in A, every 60s in B
I also used a ferri bleach (with a clearing bath before and after bleach step)

The result was very dense and low-contrast, but also very sharp - much more so than other FrankenC-41s I've tried with this film, or indeed minilab processing - and somewhat less obtrusively grainy.

The green-blue hues are very off, and there's an overall purple-blue cast (after inversion to positives I mean) but the reds rendered beautifully. The ferri bleach won't have helped, of course.

Fun to play with, but when my CD-4 runs out I'll get myself a Digibase kit.

The 75 degrees is the processing temperature, but since development stops when the developing agent is exhausted in bath B, it might not make much difference.

Since the proper image formation in C41 is diffusion controlled, and temperature affects diffusion rate....

Well, think about that for a moment when you consider agitation, temperature and the use of a 2 bath (diffusion limited) developer.

PE

It has been my understanding that with divided developers where the emulsion is saturated with developing agent in bath A, then developed to exhaustion in bath B, (the alkali), results were affected very little by changes in agitation, time, and temperature. But that is with b&w. Is color a different story due to its multiple layers?

I always like the way PE puts his responses - properly inviting a bit of thought and research on the part of his interlocutors, rather than just ex cathedra pronouncements!

I've read a tiny amount about colour photographic chemistry (one of the final chapters in Mason, and skimming that as I've no understanding of chemistry anyway); As far as agitation goes, I think dye formation takes place as a result of the oxidation of the colour developer, but it seems to be important that there is sufficient diffusion in and out of the emulsion layers and that seems to be affected by agitation rates. It is perfectly possible I have understood this grossly incorrectly of course.

As for temperature ... well, assuming that the higher the temperature the greater the diffusion rate, then presumably if one has a higher or lower temperature than designed, some layers will develop at a greater or lesser rate than others and lead to imbalanced development?Again, just having wild stabs in the dark with this thought.

There is no question that this process gives inferior development to the correct C-41 process , due primarily to the lower temperature affecting diffusion rates. I am just wondering if when using this process , there would be any difference if time, temp and agitation are increased, since development goes to completion in all three layers regardless of changes in these parameters, assuming sufficient time for it to take place.

Just some things for thought, as pdeeh says (and your comments are appreciated).

Increasing agitation allows more rapid outward diffusion into the part B and thus there is less developer for the bottom (cyan) layer. Increased temperature does much the same allowing faster outward diffusion of the CD into the solution. However, there is more to this. Oxidized developer diffuses as well and thus can move to another layer and form the wrong color, or be destroyed in the interlayer, and there is also the DIR effect to consider. These DIR fragments are there to adjust color.

Now, lets go furthr....

A C41 ISO 100 film is thinner than an ISO 400 film and thus the amount of developer absorbed in part A is different. If this does not "match" the silver quantity, then there is an "error" in development. And, BTW, this argument goes for B&W films as well.

This means that part A must be tuned for each film, as must agitation!

PE

PE said:

Oxidized developer diffuses as well and thus can move to another layer and form the wrong color, or be destroyed in the interlayer,

Click to expand...

Ah yes, that's what I didn't quite latch on to!

I've tried three or four different C-41 formulae (with quite approximate temperature control, all missing at least HAS, and always using a ferri bleach), as well as this one.

Given the complexity of colour chemistry, and the fact that C-41 was designed for machine processing using very specific chemistry and tight tolerances, it is slightly amazing to me that my rather rather rustic kitchen-sink processing has mostly produced approximately correct colour rendering! (At least as scans, I mean, and even before adjustment. Whether the resultant negatives could ever be printed correctly using RA4 is quite another matter ... )

HAS is a rather critical ingredient in C41 to act as an antioxidant and as a scavenger for oxidized color developer. It is not needed for ECN films due to the different developer formulation.

Other conditions affect sharpness and grain as well as color.

PE

Что сказать я игрался с гидроксиламином, и ни в первом ни во втором случае он не даёт хорошего результата, а вот бензотриазол исключить можно или даже заменить на калий йодид в том же колличестве, думаю результат будет хорошим. Так же скажу что CD3 тоже очень плохо работает в двухрастворном проявителе. Вот ещё вариант более менее вышел неплохим при использовании Т-32.
Осталось попробовать на CD1 и CD2 думаю будет результат более лучшим, хоть и токсичны реактивы но результат вроде лучше, но это только теория которая будет проверена практически, и да температура тоже имеет смысл, и так же заметил очень интересный результат с просроченными плёнками, в данном проявителе не проявляется вуаль.

По процессу
Извините, я пишу по-русски, я не знаю английского, я пользуюсь переводчиком, чтобы следить за форумом.

The missing link went to this
Dignan NCF-41 Divided Color Negative Developer
39 Comments by Claire Senft Published on 6th Dec 2006 13:45

In the NOV/DEC 1995 issure of Darkroom and Creative Camera Techniques Patrick Dignan wrote an article on a divided color negative developer. Everything in this article comes from that source.

Patrick Dignan, sadly now deceased, was a pioneer in the formulation of color chemistry for the home darkroom worker in the United States. As such he had earned the respect of an extensive following of home darkroom workers in compounding their own color chemistry. This article is the result of work that he did...thank him not me.

Of course as a divided developer there is at least two baths: Developing agent etc in bath A and the alkali etc in bath B. The reason for having two baths is that when the baths are combined oxidation starts with the predictable effect one must expect on shelf life. This type of developing practice of two...or more..baths has been long practiced in b&w for the same reasons. In the case present it is to provide a divided alternative to C-41 (Flexicolor) developer.

A BATH:
Water (distilled) 300 ml
Sodium Bisulphite 0.5g
CD-4 5.5 grams
Sodium Sulphite (anhy.) 4.5 grams
(?+- wetting agent?)
Water (distilled) to make 500 milliliters
pH at up to 75ºF: <6.6
Time in A bath (including drain time): 3 min.(minimum)


B BATH
Water (distilled): 500 ml
Potassium Carbonate 53 g
Potassium Bromide 0.5g
Water (distilled) to make 1 liter.
optional: BTA 2mg (0.2ml of 1%)
pH at 75ºF: 11.8 (or less = better = 11)

Time in B bath 6 minutes (minimum)

As you can see not a difficult formula to put together. There is no need to be able to measure any closer than 1/10th gram

Shelf life has exceeded 1 year. Use an acetic acid stop bath. I, in lieu of anything else, I would recommend 20% vinegar to water
Coventional bleach and fix or blix as otherwise used. 75ºF can be used with extended time - v.s.

Since there is some carry over every time film is developed you will eventually find your self with insufficient stock to cover your film. That is when you will need to make more. The amount of time elapsed from compounding should not matter. NEVER GET ANY B BATH INTO A BATH OR YOU WILL CAUSE THE A BATH TO START OXIDIZING.

THIS DEVELOPER IS DESIGNED TO WORK WITHOUT A PREWET BATH
Since the time in A bath is used only to absorb developing agent and because the agent will be fully utilized in B bath you can not over develop your color film.

This is designed for tank processing. I do not see a method for use with a JOBO unless you reclaim your ingredients.

Try this as it is as easy and as economical as you will ever find.