A Color Monobath Developer Formula

I found a formula for a color monobath developer in a book, which claims to develop and fix color negative film in a single step at room temperature in just 2 minutes. I'm quite skeptical about this, but I currently don't have the means to test it. I'd like to hear everyone's thoughts on this formula.

Monobath Developer Formula

• Water: 750 mL
• CD-4: 4 g
• Anhydrous Sodium Sulfite: 10 g
• Anhydrous Sodium Sulfate: 60 g
• Potassium Bromide: 3 g
• Sodium Hydroxide: 52.5 g
• Sodium Thiosulfate: 25 g
• Add water to make a final volume of: 1000 mL

There's no way that the formula as stated will produce anything close to correct C41 development. However, I don't doubt that there will be some kind of color negative image and that it may be satisfactory for some users. Then again, even if that's the case, I struggle to see the advantage of this approach.

Off the top of my head I don't see a bleaching agent so presumably it's gonna result in something like a bleach bypass?

No way. You will need a bleach in any color process. And you still would need to fix after bleaching, so adding fixer in color developer would be not a very good idea. You would get some kind of result though, nut it is hard to predict. I can guarantee though, it is not even close to the industry standards of a C-41 negative, nor do I know, is it even properly fixed.

xiaruan said:

CD-4: 4 g

Click to expand...

The amount of CD4 in your formula is too low for it to be ready in the 2-minute development time you suggest, assuming you develop at 38°C. I have a Kodak patent for a developer formula that promises to develop your film in 1 minute at 48°C and uses a much higher amount of CD4. Remember that after color development, your film will contain three main components: metallic silver, silver halide, and azo dyes.

At the end of our process, we want to keep only the azo dyes and eliminate the metallic silver and silver halide that didn't develop in the developer. How do we do that? In the bleaching step, we convert the metallic silver back into silver halide so that the fixer can completely remove the silver present in the emulsion. Skipping the bleaching step will leave your emulsion with azo dyes and metallic silver, the latter of which will affect any printing/scan process you want to perform later.

Josaw98 said:

The amount of CD4 in your formula is too low for it to be ready in the 2-minute development time you suggest, assuming you develop at 38°C.

Click to expand...

You might or might not be right, but notice that the developer is extremely alkaline (Sodium Hydroxide: 52.5 g) and that level of alkalinity would most likely make this developer very active.

These 4 grams are not that small. It is not clear what the pH of this broth is. There is an absurd amount of hydroxide. However, there is also 10 grams of sulfite, which will block the formation of dyes to some extent. If this thing works somehow, as has already been said, the bleach is missing. When you think about it, there is no way to combine them.
The position of the sulfate is interesting - I suppose it is there, as a measure to protect the thiosulfate, but I do not know if this will work.
If the amount of sodium sulfite is enough to completely block the formation of dyes, this could be a formula for developing color film as black and white.

The book also includes a description of the principles behind this formula, but it seems there are some issues with it as well. However, since I'm not very familiar with color development, I can't pinpoint exactly where the errors lie.
The monobath development and fixation method proposed by the American 3M Company performs development and fixation simultaneously during color development. This process eliminates the bleaching step, leaves no silver residue, and produces satisfactory color images. The main components of the processing solution are color developing agents and fixing agents, and the solution is strongly alkaline (pH ≥ 13.2). Various types of color developing agents can be used in the monobath solution, but CD-3 or CD-4 are typically selected. The fixing agent usually chosen is sodium thiosulfate, but alternatives such as thiocyanate, mercaptosuccinic acid, and thioglycolic acid can also be used.

Excellent results can be achieved when using the monobath method to process various types of film.

The reason why the silver image does not affect the color image when using the monobath processing method is as follows: When silver halide is directly reduced and developed from its solid state, the resulting silver image has high covering power. However, when it is dissolved in the processing solution to form silver ions or silver complex ions, and then reduced and deposited on the latent image, the resulting silver image has low covering power. The monobath processing solution contains fixing agents that dissolve the silver halide particles. Even if the silver image increases proportionally with the dye image, the density of the silver image remains low, allowing light to pass through the silver image effectively. This ensures that the quality of the color image remains unaffected.

I'm very skeptical about this formula, but there's nothing stopping me from trying it - it's simple enough. I might try it just to see what would happen, although I have very little CD-4 - I would change it to CD-3, of which I have a lot, but it's hard for me to estimate how much I would need, due to the different activity.

Raghu Kuvempunagar said:

Puede que tengas razón o no, pero ten en cuenta que el revelador es extremadamente alcalino (hidróxido de sodio: 52,5 g) y ese nivel de alcalinidad probablemente haría que este revelador fuera muy activo.

Click to expand...

It's good that you mentioned it; that's another serious problem. It's very alkaline, but I don't see a buffer anywhere. The color depends heavily on the pH, and such a high pH will almost certainly result in a dominant color, a huge color shift. All the formulas I've seen are always between pH 10.05 and 10.1. Just because it's so alkaline doesn't mean it will work. It will probably spoil quickly because the amount of sulfite is very low for that large amount of NaOH, and that raises another problem. On the one hand, a pH >13 will rapidly decompose the CD4, and that amount of sulfite will interact with the CD4, also reducing its effectiveness. It's recommended to use low amounts of sulfite (<1 g/L) when working with color developing agents, such as CD2, CD3, and CD4. That's why HAS or any hydroxylamine derivative is used in C41, as it works in conjunction with sulfite as a preservative. This monobath will probably decompose in 1 or 2 hours.

xiaruan, who is the author of the book and from where was this formula obtained? Were there any pictures of the negatives that were made from this formula?

Thanks

pentaxuser

xiaruan said:

Even if the silver image increases proportionally with the dye image, the density of the silver image remains low, allowing light to pass through the silver image effectively. This ensures that the quality of the color image remains unaffected.

Click to expand...

The notion that the image "remains unaffected" is, I think, a little (too) optimistic. This monobath can be expected to work as a bleach-bypass process with a significant color shift as well as crossover to boot. As I initially remarked, the results may be satisfactory to some. They will certainly not be excellent by any means. "Adequate", perhaps.

The concept is entertaining, but in my view lacks practical relevance apart from this novelty aspect.

@xiaruan: Is this formula meant for processing C41 films? Or a predecessor?

Josaw98 said:

It's recommended to use low amounts of sulfite (<1 g/L) when working with color developing agents, such as CD2, CD3, and CD4. That's why HAS or any hydroxylamine derivative is used in C41, as it works in conjunction with sulfite as a preservative.

Click to expand...

Sodium sulfite is a dye formation inhibitor, so it is something to avoid in a CD formula.

halfaman said:

Sodium sulfite is a dye formation inhibitor, so it is something to avoid in a CD formula.

Click to expand...

Well, avoid in excess. A small amount of sulfite is generally present in color developers. I assume this plays a role in avoiding excess dye formation esp. in areas that should receive little to no development.

koraks said:

Well, avoid in excess. A small amount of sulfite is generally present in color developers. I assume this plays a role in avoiding excess dye formation esp. in areas that should receive little to no development.

Click to expand...

I was refering more to the formula of this thread. According to PE formula coming from Kodak, there is 0.38 grams of sodium sulfite per liter of CD. In this formula there is 10 grams. And sodium sulfite is a powerful dye inhibitor.

halfaman said:

According to PE formula coming from Kodak, there is 0.38 grams of sodium sulfite per liter of CD.

Click to expand...

Additionally there is 2.78 g Sodium Metabisulphite in PE formula as per this blog.

Given the very high alkalinity of the monobath recipe, it would not be surprising if excessive dyes are formed and therefore need more Sulphite than usual. But there is no point in speculating what a test can tell especially when one hasn't worked with a similar recipe previously. So, OP, if you test this recipe, please do share your results. However, unless you are really curious and want to have some fun, it is probably best not to waste money on this.

Raghu Kuvempunagar said:

Additionally there is 2.78 g Sodium Metabisulphite in PE formula as per this blog.

Click to expand...

I missed that in the formula, thanks for pointing out my mistake. But I insist the sodium sulfite is a strong color restrainer in my experience.

xiaruan said:

I found a formula for a color monobath developer in a book, which claims to develop and fix color negative film in a single step at room temperature in just 2 minutes. I'm quite skeptical about this, but I currently don't have the means to test it. I'd like to hear everyone's thoughts on this formula.

Monobath Developer Formula

• Water: 750 mL
• CD-4: 4 g
• Anhydrous Sodium Sulfite: 10 g
• Anhydrous Sodium Sulfate: 60 g
• Potassium Bromide: 3 g
• Sodium Hydroxide: 52.5 g
• Sodium Thiosulfate: 25 g
• Add water to make a final volume of: 1000 mL

Click to expand...

Please provide your reference - title and author of the book you cite...

Since it's Chinese material, what I uploaded earlier is my translated version.

I took the liberty of translating the entire thing.

Darkroom Pictures. Regular and stunt production
by Xu Dong, Yi Jianping, and others
Hunan Science and Technology Press

page# 185


10. Typical Formulation of Integrated Developer and Fixative Washing Solution for Color Photosensitive Materials

Conventional processing of color negatives and color photographic paper is lengthy and cumbersome. Therefore, it is necessary to innovate the process and simplify the formula. Although the combined bleaching and fixing method is an improvement over the conventional method, it is still not ideal. The combined color development, bleaching, and fixing processing method is the most ideal method, but because the effects of color development and bleaching are opposite, the bleaching agent will undergo an oxidation-reduction reaction with the developer, making the properties of the processing solution unstable, thus making processing impossible and making it difficult to guarantee the quality of processing.

The integrated developing and fixing method proposed by 3M in the United States involves fixing the image while developing it. This simplifies the bleaching process, eliminates silver residue, and yields satisfactory color images. The main components of the developing solution are the color developer and the fixer, and the solution is strongly alkaline (pH ≥ 13.2). Various types of color developers can be used in the developing and fixing solution, but CD-3 or CD-4 are commonly chosen. The fixer is usually sodium thiosulfate, but thiocyanate, mercaptosuccinic acid, and mercaptoacetic acid can also be used.

Good results can be obtained by using a combined developing and fixing bath to process various types of film.



Formula for a combined bath with styrax and styrax (Part 1)

water 750 mL


CD-4 4 g

Anhydrous sodium sulfite 10 g

Anhydrous sodium sulfate 60 g

Potassium bromide 3 g

sodium hydroxide 23~105 g

sodium thiosulfate 25~125 g

Add water to

1000 mL



Formula for a combined bath with styrax and styrax (Part 2)

water 750 mL

CD-4 4 g

Anhydrous sodium sulfite 10 g

Anhydrous sodium sulfate 60 g

Potassium bromide 3 g

sodium hydroxide 52.5 g

sodium thiosulfate 25 g


Add water to 1000 mL

Note: Use the second formula of the combined bath solution. Rinse for 2 minutes at room temperature, then wash with water and dry.

The use of a combined developer-fixer wash for developing silver halide does not affect the color image because when silver halide is directly reduced and developed from a solid, the resulting silver halide has high covering power. However, when it dissolves in the developing solution, forming silver ions and silver complex ions, and is then reduced and precipitated onto the latent image, the resulting silver halide has low covering power. The combined developer-fixer wash contains a fixer that dissolves silver halide particles. Even if the silver halide increases proportionally to the dye image, the silver halide density remains low, allowing light to pass through well and ensuring that the color image quality is unaffected.

Formula for a combined bath with styrax and styrax (Part 3)

water 750 mL

sodium thiosulfate 61.25 g

Anhydrous sodium sulfate 75 g

Anhydrous sodium sulfite 12.5 g

Potassium bromide 3.75 g

sodium thiocyanate 1.25 g

sodium hydroxide 115 g

CD-4 5-20 g

Add water to 1000 mL

Note: When using this one-bath developer-stabilizer formula, rinse for 4 minutes at room temperature. The density change of the dye image is minimal when the developer concentration is between 5 and 20 g/L, because the concentration of the developer in the emulsion layer depends on the diffusion rate.

Here is a related work for the interested and one that supposedly works at pH 10.6:



And another one that is more close to what @xiaruan shared (pH ~13.2):

Can I ask what "styrax" is and what you do with parts 1,2, and 3 ? Each one just seems to be a variation in the amounts of the same ingredients If the colours are satisfactory( depending on how this is defíned), I wonder why in the long history of film processing somebody such as Kodak, Fuji or Agfa didn't come up with a process like this?

pentaxuser

I'm also curious what styrax is. According to search engines, it's a balsamic resin obtained from the cut trunks of trees of the Styrax genus.
But I can't be sure that Google Translate simply made a mistake in translating, or rather OCR reading, the Chinese characters.

Perhaps OP could dispel our doubts.