Newbie DIY C-41 Recipe/Formula/Process

[Rudeofus]

So 60% is a sensible solution, since that is almost the saturation level (173g/100ml).

It would be helpful if it was always noted which it was - weight/volume or weight/weight or volume/volume. Normally, in the various things we mix up to make these formulas, we have convenient w/v solutions of stuff like phenidone, benzotriazole, potassium bromide.

Yes, I have struggled with this myself. I had to titrate my batch of FeCl3 40% solution because nobody could tell me. A search for "Ammonium Thiosulfate 60% solution" at least gave me enough hits mentioning "w/w" to assure me.

PE once told me: "you can weigh much more accurately than you can measure volume, therefore chem manufacturers prefer w/w". I took this as a hint to assume w/w except where stated otherwise.

 

[koraks]

@Rudeofus thanks for the correction!

It would be helpful if it was always noted which it was

Yeah, definitely.

 

[bernard_L]

I know its an old topic.
Where I live I cant source cd-4 or its very expensive. I can get CD-3 cheap. Hows CD-3 to CD-4? can I use one instead of another or its totally different and needs for different recipe?

Suvatlar lists both CD3 and CD4 at reasonable prices, and ships to EU at least.

https://www.moersch-photochemie.de/wp-content/uploads/2023/04/Preisliste-online-2023.pdf

 

[emkei]

Ammonium Thiosulfate solution is typically sold as 60% w/w solution. You can make 1 kg of Ammonium Thiosulfate 60% solution by mixing 625g (= 600g / 0.96) of your dry powder with 375g water to make 1kg of Ammonium Thiosulfate 60 solution. With a density of 1.325 kg/l this kg will equal 0.75 liters. To make a full liter of Ammonium Thiosulfate 60% solution, you'd have to mix 828g of your powder into half a liter of water.

PS: If the 4% "other stuff" in your powder are not that soluble, you may end up with a milky liquid. It doesn't matter for all practical purposes.

now i have only 400 grams that 96% powder of Ammonium Thiosulfate... can you tell me how to mix it with this ammount?

 

[koraks]

now i have only 400 grams that 96% powder of Ammonium Thiosulfate.

So assuming 60% w/w, your 400g are 60% of the total weight, which would make the total weight 400/60 * 100 = 667g. Add 267g water to your 400g thiosulfate.

Btw, I second the comment from @Rudeofus about ending up with a milky liquid. In my experience, it's milky with some yellowish sludge floating on top. I always filter it through a fine mesh cloth a couple of times to get rid of it.

 

[lamerko]

A while ago I had asked the local chemist about dry ammonium thiosulphate - they had it in stock but the price was hellish. Also, the store warned me that ammonium thiosulfate is stored very poorly - it quickly begins to disintegrate, probably from there the sediments. At the same time, the price for a 60% w/w solution is very low and there was no problem with storage. Unfortunately, the minimum orders were a thousand liters. I ended up getting 5 liters of 60% solution from Suvatlar for 45 euros, which contains over 4 kilograms of dry thiosulphate equivalent.

 

[Anon Ymous]

At the same time, the price for a 60% w/w solution is very low and there was no problem with storage. Unfortunately, the minimum orders were a thousand liters. I ended up getting 5 liters of 60% solution from Suvatlar for 45 euros, which contains over 4 kilograms of dry thiosulphate equivalent.

Perhaps you should look at the right place. I buy it as a fertiliser at 1, 5 and 15l bottles. The 5l ones cost about 20€ nowadays. 1l cost me 7€ back in July.

 

[lamerko]

Perhaps you should look at the right place. I buy it as a fertiliser at 1, 5 and 15l bottles. The 5l ones cost about 20€ nowadays. 1l cost me 7€ back in July.

I searched - I called 4-5 importers, talked to agrarian pharmacies. The first require industrial quantities, and the others do not provide ATS as an independent product, but only in combination with nitrogen fertilizer... I'm just tired of arguing - they just don't understand me for what purpose I want it.
By the way, I visit Greece from time to time - if I can get it directly from somewhere convenient for me, that would be great

 

[Anon Ymous]

@lamerko The product I buy is called Thio-Sul.

 

[lamerko]

Thanks. I'll look, but I still have stock at the moment

 

[emkei]

hi guys, i want to ask how many films can i develop with this developer? is 20 enough? or can I try a little more?

 

[lamerko]

This is a formula with rounded weights close enough to the patent. But with a missing chelating agent - this implies a shorter shelf life. Although it can last months with luck. Personally, I would use it for 4 rolls per liter.

 

[emkei]

I used the first batch on 20 rolls with good results. now with the second batch I'm already on 18 rolls. I was just curious...
I extend the developing time by 2% per film

 

[Rudeofus]

Tetenal's instructions provided C-41 CD times for up to 16 rolls per liter, and if you are willing to really stretch it and are willing to do some corrections in digital post, you can easily get up to twice that.

 

[emkei]

I extend the developer time, like I said before by 2% per roll. i extend the fixer time just slightly - 10 min for the 20th film (from starting point 6.5 min)
and I want to ask about bleach, because there I use 3 min with no change. it is OK?

 

[lamerko]

I used the first batch on 20 rolls with good results. now with the second batch I'm already on 18 rolls. I was just curious...
I extend the developing time by 2% per film

How long did it take you to develop these 20 rolls? For me, the problem is actually the time, not the amount of films...

 

[emkei]

within 2 months i guess. three months would be my limit

 

[Rudeofus]

I extend the developer time, like I said before by 2% per roll. i extend the fixer time just slightly - 10 min for the 20th film (from starting point 6.5 min)
and I want to ask about bleach, because there I use 3 min with no change. it is OK?

While you immediately recognize poorly developed C-41 materials, incomplete fixing will hit you with a vengeance some years down the road. At the same time neutral fixer is easily available outside of packaged kits, so there really is no reason for stretching fixer to the limit.

Regarding bleach: it lasts seemingly forever. If you use it, it gets reduced, and aerial Oxygen will bring it back. While Oxygen will restore the oxidizer in your bleach, it raises pH, and at higher pH your bleach will become slow to ineffective. If you have no pH meter, then I recommend the "fizzle test" to check, whether your bleach is still acidic and therefore active: add a few grains of Sodium Bicarbonate (aka baking soda) to your bleach. If the grains start fizzling (=releasing Carbon Dioxide), you bleach is good. If these grains don't fizzle, then add some acid: battery acid, acetic acid, swimming pool "pH down", whatever you can find to get pH down far enough, that more grains of bicarbonate will fizzle again.

Another factor affecting bleach is dilution: every time you carry over washing water into your bleach, you effectively bring water into your bleach. This will dilute your bleach as you keep reusing it. Since the only way to correct for that would be "add fresh bleach concentrate", and since "fresh bleach concentrate" is not as easily available as "neutral fixer", you have to plan for longer bleach times even if you restore acidity of your bleach.

 

[Sky taner]

As part of my quest to DIY C-41, I've put together a shopping list that I intend to try out and thought I'd share it with the group for input before I pull the trigger and buy (would hate to buy the wrong thing). Since I'm a hybrid shooter, my goal is get something that will be scannable/digitizable more than printable via analog means.

A couple of things to note: I'm not a professional chemist, but I'm very technically inclined. I realize that I'm new at DIY C-41 and probably don't know what I don't know, so please just point me the right direction if I'm going the wrong way about something and heading for disaster. I'm not going to bite.

With that:

# C-41 Recipe/Formula (updated 2016-10-19, thanks RPC & sfaber17 for input!)

- C-41 Developer:
1. 700ml distilled water
2. 34.0g Potassium Carbonate (Artcraft Part #1250, $17.00)
3. 3.5g Sodium Sulfite (Artcraft Part #1416, $16.50)
4. 1.5g Potassium Bromide (Artcraft Part #1420, $12.25)
5. 2.0g Hydroxylamine Sulfate (Artcraft Part #1716, $16.00)
6. 2.0mg Potassium Iodide (note milligrams, not grams) (Artcraft Part #1290, $15.75)
7. 5.0g CD-4 (Artcraft Part #1095, $37.50)
8. Add distilled water to bring it to 1000ml.
9. Test ph, add Sodium Bicarbonate (baking soda) to bring ph down to 10.1, likely 1-3g. must experiment.

- C-41 Stop Bath:
1. 700ml distilled water
2. 10ml Glacial Acetic Acid (Artcraft Part #1689, $10.59)
3. Sodium Sulfite (Artcraft Part #1416, $16.50, purchased as part of developer above)
4. add distilled water to make 1000ml

- C-41 Bleach:
1. 700ml water
2. 80.0g Potassium Ferricyanide (Artcraft Part #1280, $18.00)
3. 20.0g Potassium Bromide (Artcraft Part #1420, $12.25, purchased as part of developer above)
4. Add water to make 1000ml

- C-41 Fixer:
1. 700ml water
2. 160ml Ammonium Thiosulfate, 60% (Artcraft Part #1050, $9.95)
3. 1.0g EDTA Disodium (Artcraft Part #1130, $16.00)
4. 11.0g Sodium Metabisulfite (Artcraft Part #1375, $6.25)
5. 2.5g Sodium Hydroxide (Artcraft Part #1759, $9.00)
6. Add water to make 1000ml.
7. Test ph, add Acetic Acid or Sodium Bicarbonate to get ph to 6.5

- C-41 Stabilizer: (per PE on APUG, definitive word on color stabs forum thread)
1. Photoflow 200 mixed per directions on bottle to make 1000ml.
2. 10 ml Formalin 37%

# Process (100F/38C)

1. 01:00 Pre-wet/temper
2. 03:15 Developer
3. 00:45 Stop Bath
4. 04:00 Rinse (8x 00:30)
5. 03:00 Bleach
6. 03:00 Rinse (6x 00:30)
7. 06:30 Fixer
8. 06:30 Wash (8x 00:30)
9. 01:00 Stabilizer

Hello I am trying to follow your recipe, how much sodium sulfite in the stop bath part should I added?

 

[lamerko]

About 10 grams - has a purifying effect. However, you will need a pretty good wash before bleaching. If you use standard DTPA C-41 bleach, it is not so important.

 

[Sky taner]

About 10 grams - has a purifying effect. However, you will need a pretty good wash before bleaching. If you use standard DTPA C-41 bleach, it is not so important.

Thanx bro I will try the recipe then

 

[lamerko]

This is a simplified formula - I haven't tried it, but it will probably work. It's pretty close to patent.