C41 Formulas

[chassis]

Hello all

Thanks to Mr. Mowrey for his many contributions to the film community.

I'm preparing to enter the self-processing world for color film, after 35 years of black and white.

Is making homebrew C-41 chemistry more economical than buying Flexicolor lab chemistry? I will process a half dozen sheets of 4x5 and as many rolls of 120 film per month.

Thanks for any replies.

 

[fdonadio]

Is making homebrew C-41 chemistry more economical than buying Flexicolor lab chemistry?

I wouldn't say that it's really that much cheaper. I didn't do all the needed math, but...

I dare say it's easier (and, maybe, cheaper) for americans and europeans living in big cities or near them. As you know, color chemistry is classified ORM-D, which means it can't be shipped by air, only ground.

In my country (Brazil), I can buy Flexicolor chemistry and it's not that expensive, but Kodak distributors have minimum order policies, which makes it uneconomical.

Another advantage of scratch mixing is that you can prepare one or two liters and use immediately, without worrying about storing mixed chemistry for long and losing it.

YMMV.


Cheers,
Flavio

 

[chassis]

Thanks for the reply Flavio.

 

[Photo Engineer]

I myself don't mix from scratch! My time is more valuable than that and I prefer buying kits off the shelf. I understand why some prefer mixing and do it yourself, but if you factor in your time and other minor (or major) glitches that might take place, it really isn't worth it.

There probably will be a firestorm over this one.

PE

 

[Gerald C Koch]

Obviously whether it is cheaper often depends on where you buy the chemicals. It pays to shop around. Then too some chemicals are harder to find or obtain in small amounts. The same applies to B&W chemistry. You must salso consider an investment in a good scale. A magnetic stirrer is also useful as are a few pieces of laboratory glassware. Kitchen cup measures are not very accurate in my experience. While not absolutely necessary it also pays to have some knowledge of chemistry.

 

[fdonadio]

I dare say it's easier (and, maybe, cheaper) for americans and europeans living in big cities or near them.

I don't know what I was thinking last night, but I wasn't clear enough.

What I meant: it's probably easier (and cheaper) to buy Flexicolor chemistry if you live in places where you can find them easily.

Scratch mixing is an option for those that can't find Flexicolor chemistry easily or have such a low volume that the chemistry would go bad.

But then there's the problem of finding the raw chemicals and the gear needed, as noted by @Gerald C Koch.


Cheers,
Flavio

 

[BMbikerider]

I cannot verify the fact, but a main supplier of photographic processing chemicals in the UK has stated that all of the C41 (apart from Kodak and Fiji) is a generic concoction made by one company in Europe and sold under different lables. (Tetenal, Rollie are just two of them).

I have not actually used Flexicolour (knowingly) but I have used FUJI and to be honest I cannot tell the difference between that and the different brews made in Europe. Even when printing, the difference in colour balance is minimal and this could be down to my developing technique, not the chemicals themselves.

If Flexicolour is made by the same manufacturer as the Ektacolour RA4 print developer then it comes from China.f

 

[Anon Ymous]

... You must salso consider an investment in a good scale. A magnetic stirrer is also useful as are a few pieces of laboratory glassware. Kitchen cup measures are not very accurate in my experience. While not absolutely necessary it also pays to have some knowledge of chemistry.

A scale is obviously important and a cheap 10mg resolution scale is probably more than enough. I got one with 100g maximum capacity and wouldn't like to get one with greater capacity. I calibrated and checked it against a far more expensive real lab scale and it works a treat. It might be a bit off at the very low end of the scale, but in such cases, it's IMHO better to measure a larger quantity and make a solution of known concentration, like 1%. Lab glassware is fairly cheap, so I'd say it's not a bad idea.

The magnetic stirrer on the other hand is IMHO an overkill. At the prices these units fetch, I think I'd rather use stir rods and preheat water somewhere else. Then, there's one thing that is probably essential for colour work: a pH meter. Colour work is far less forgiving than bw and you can't really target a pH unless you have a pH meter.

 

[fdonadio]

If Flexicolour is made by the same manufacturer as the Ektacolour RA4 print developer then it comes from China.

Flexicolor is a Kodak trademark. It's what they call their C-41 and RA-4 chemistry these days.

 

[Rolfe Tessem]

It is worth mentioning that the genuine Flexicolor chemistry has some preservatives in it to prolong its life. According to Dominick Vacco at Kodak Alaris, the formulation has recently been updated to improve the longevity even more, in an era of diminished mini-lab traffic.

 

[RPC]

Flexicolor is a Kodak trademark. It's what they call their C-41 and RA-4 chemistry these days.

Flexicolor refers to the C-41 process only, not RA-4.

 

[RPC]

As many of us know color chemistry is getting harder to source, and could get worse. Seeing this coming, about 10 years ago I decided to investigate mixing my own and found success. I still have Kodak chemistry that I am using but when it runs out I plan to just mix my own from scratch as I don't want to worry about what the marketplace is doing anymore in terms of color chemistry. I have plenty of color film, paper, CD-3 and CD-4 in cold storage and use a ferricyanide bleach. I think the other chemicals will be available for quite a while so I am hoping to be able to do color for years to come.

 

[BMbikerider]

Flexicolor refers to the C-41 process only, not RA-4.

I will go along with that comment. My present box of RA4 concentrates (20 ltr) (bought a month ago) is very clearly labled Kodacolor both on the box and on each bottle.

 

[RPC]

I will go along with that comment. My present box of RA4 concentrates (20 ltr) (bought a month ago) is very clearly labled Kodacolor both on the box and on each bottle.

Interesting. IIRC, mine was labled Ektacolor (10 liter). I am in the states, perhaps that is the difference.

 

[fdonadio]

Flexicolor refers to the C-41 process only, not RA-4.

I will go along with that comment. My present box of RA4 concentrates (20 ltr) (bought a month ago) is very clearly labled Kodacolor both on the box and on each bottle.

Interesting. IIRC, mine was labled Ektacolor (10 liter). I am in the states, perhaps that is the difference.

Yes, sorry for my mistake. Just took a look at Kodak-Alaris Brasil price list and RA-4 is called "Kodacolor" here.

 

[fdonadio]

The Formulary used to sell it, but you can make it from EDTA + 28% Ammonium Hydroxide + FeCl3 (Ferric Chloride). Just mix them in the ratio of 1 Mole, 4 Moles and 1 Mole and add a 10% excess of EDTA. And, use caution. The 28% AH is nasty stuff. I used to do this all the time before the manufacturing line for the salt was up and running.

Where does the Cl- go? Looks like some water will be produced and some hydrogen will be released in the air. But, as the Fe-NH4-EDTA is soluble in water, I am trying to figure out how much impurity will be in the solution and how to get it out.


Cheers,
Flavio

 

[Photo Engineer]

Well, this is pretty acid, and the working strength is supposed to be at pH 5.5 to 6.5. So, you will find that EDTA is not very soluble in water, but dissolves very well in the AH. When you add the FeCl3, it forms a complex and you end up with Ammonium Ferric EDTA Chloride and some Ammonium Chloride.

PE

 

[fdonadio]

you end up with Ammonium Ferric EDTA Chloride and some Ammonium Chloride

Thanks for the explanation?

Should I do anything or just live with that?

I never really understood organic chemistry well enough.

 

[Anon Ymous]

Where does the Cl- go?

Treat the Ferric Chloride with a base and you should get Ferric Hydroxide. Even bicarbonate will do the trick, but it will bubble a lot, so it can be messy. You'll get a brown sludge (Ferric hydroxide is insoluble), which you have to wash and use as is to react with EDTA. Should be doable and there will be no Chloride ions.

 

[Photo Engineer]

Ferric Hydroxide does not react with EDTA at room temperature and pressure. It requires a quite elaborate method of manufacture. See the patent by Steven and Surash from EK.

And that method above is what I used in some of my early work to make the first RA4 type Bleach-Fix at Kodak.

PE

 

[fdonadio]

Treat the Ferric Chloride with a base and you should get Ferric Hydroxide. Even bicarbonate will do the trick, but it will bubble a lot, so it can be messy. You'll get a brown sludge (Ferric hydroxide is insoluble), which you have to wash and use as is to react with EDTA. Should be doable and there will be no Chloride ions.

Thanks, Anon, for keeping that chlorine away!

I happen to have sodium hydroxide, which should work great and give me NaCl as byproduct — which I can separate by filtering or through a stopcock, after centrifugation.

... But I suspect Fe(OH)3, being a base, won't work the same as FeCl3, which is acidic. But maybe EDTA will want to bond with that iron stronger than the OH ions.

EDIT: @Photo Engineer just confirmed my suspicions.


Cheers,
Flavio

 

[fdonadio]

PE,


In that post up there, I meant to really thank you, not ask you a question. Somehow, I typed the wrong sign. Sorry.

So, my question remains: did you just use the resulting solution as it was? Or did you purify the ferric ammonium EDTA chloride?


Cheers,
Flavio

 

[Anon Ymous]

Ferric Hydroxide does not react with EDTA at room temperature and pressure. It requires a quite elaborate method of manufacture. See the patent by Steven and Surash from EK.

And that method above is what I used in some of my early work to make the first RA4 type Bleach-Fix at Kodak.

PE

Oh, that would be a bummer.

Anyway, I'm also wondering if the ammonia solution can be substituted by treatment with ammonium bicarbonate. That should take care of the stench, when dealing with ammonia.

 

[Photo Engineer]

Flavio, I did not purify it.

I don't know if Ammonium Bicarbonate could be used. I never tried it.

PE

 

[fdonadio]

So, I'll be using it as it will be. If it worked for PE, it will work for me.

Thanks, again, PE and everyone involved.