C41 process at home

[Scuba_Phil]

Hello out there...

I have been doing my own B&W developing at home for some time now and I love it. But recently I have gotten a wild hair to try my hand at trying to develop some of my color films. I was wondering if anyone could help me out with how the process would work (for a beginner) or if you know of any good materials that I could teach myself how to develop the C41 films that I have. I appreicate any and all help on this one.

Thanks,
Phil.

 

[Akki14]

Presoak (turns dark green due to washing out the antihaliation layers - scary when you first do it because no one warns you of these things!!)
Developer, about 3minutes15seconds depending on kit or process
stopbath (semi-optional) 30seconds
Blix or bleach then fix
Warm water rinse (3+ minutes)
Stabliser (about 1 minute)

C-41 and colour film is pretty much standardised. You don't change anything usually. Faster ISO film deplenish your developer more than the lower ISOs. There's not much else to it. I keep everything warm in a big storage tub of water and check the temperature with a thermometer probe.

Someone else will probably come along and tell you the more specifics and what you should and shouldn't do. I'm a maverick and get told off for using Blix so I'll shut up now. I'll just say that I've not had any problems so far and I've done 12 rolls without problem.

 

[Ian Grant]

As Heather says C41 film processing is very simple and by far the easiest kit to use is the Photocolor II kit, which has been around for years now, and is generally regarded to be one of the best on the market.

The only really critical stage is the Colour Development but its easy to keep the temperature stable for such a relatively short dev time with a developing tank and a bowl of warm water.

I've processed many hundreds of rolls of C41 films over the years with no problems.

Ian

 

[AgX]

Akki,

No one wants you to shut your mouth, I assume. You have been using the chemistry and procedures (except for the presoak) of a renown manufacturer. I’m doing the same.

 

[Akki14]

eh? I do presoak. The directions that came with my kits says to do a 5minute presoak.
I just use Blix instead of Bleach and Fix separate steps. I never thought to not do a presoak, actually... I think a presoak gives me more leeway with my timings to a point because my film isn't getting cold otherwise. I'm just not using a jobo system or the like...

Ian, What brand is the Photocolor II kit? I've never heard of it.. just Tetenal and Speedibrews and a few other brands for c-41. I use a Tetenal liquid c-41 kit.

 

[Ian Grant]

Heather, Photocolor has been around for a long time, the company who originally made it were the successors to Johnsons Photochemicals, Pip Pippard was the chemist.

Now I think they are made by Paterson. But for many years they were predominant in the UK market for their C41, RA4 and E6 kits.

It's available online at Retro, but maybe its not currently manufactured, Paterson have only just resumed B&W chemistry after their outsource manufacturer stopped making photo-chemicals in the UK.

Ian

 

[Photo Engineer]

I always say "Use what works for you", and you should.

I like to point out that a good film blix must be very energetic. So much so that it can decompose the blix by destroying the iron complex and the fixing agent. Therefore, most film blixes are too weak to remove all of the silver from the film.

This small amount of silver can desaturate the color and can give a grainier image.

This is why Kodak, Fuji and Agfa never released a blix for any color film product.

So, these companies recommended a C41 process which was prewet, color developer, bleach, wash, fix, wash and stabilze (called final rinse now).

A stop can be added between the developer and the bleach, but I have never needed one. It is usually 1% or 2% acetic acid.

PE

 

[Shypii90]

So am i considering processing my own films at home so thanks for starting this thread Scuba_Phil.

So just to get it confirmed the steps must be:
Pre-wet/soak, Developer, Rinse/Stop-bath?, (Bleach, Wash, Fix)=(Blix), wash & stabilize.

Is everything usually included in the kit? And at what temperatures do you have to pre-wet the film with?

I'd appreciate anyone's answers. Thanks.

 

[Akki14]

100F for the pre-wet, 100F for the development, sticking as closely as possible to that 100F. The blix, wash and stabliser can be around 100F but not so strictly adhered to depending on the kit. The stabliser in my kit can even be used at room temperature days after you've done everything else, but I do it after I finished my rinsing because it's just easier that way.
If you get a "press kit" you may only have developer and blix. I recommend the Tetenal Rapid kit because it has everything in liquid form and includes stabliser. The pre-wet/soak is just normal tap water, ditto the rinse water (though that should be warm, not cold... pain in the butt for me with a really poorly on-demand boiler!). The optional stop-bath can just be the usual stopbath you use for B&W developing but keep the working solution just for c-41 to avoid cross contamination. My kit says the stopbath just helps keep the blix from going bad sooner but it's optional, so I'm not sure if you'd bother with a rinse inbetween the developer and blix (or bleach and fix steps).

If you're used to doing B&W, it's not really that different if you think about it.. you have your developer, your stopbath (which is semi-optional just like in B&W), your fix (but it has added bleach in or you have the extra bleach step), then rinse, then you can think of the stabliser as the equivalent of photo-flo, so you don't rinse it off afterwards but just hang it up to dry with it dripping off.

 

[Photo Engineer]

So am i considering processing my own films at home so thanks for starting this thread Scuba_Phil.

So just to get it confirmed the steps must be:
Pre-wet/soak, Developer, Rinse/Stop-bath?, (Bleach, Wash, Fix)=(Blix), wash & stabilize.

Is everything usually included in the kit? And at what temperatures do you have to pre-wet the film with?

I'd appreciate anyone's answers. Thanks.

If you do not use a stop, don't rinse. Go directly into the bleach. I suggest prewet/develper/stop/bleach/wash/fix/wash/stab or prewet/developer/bleach/wash/fix/wash/stab.

A water rinse after the color developer with no stop can introduce crossover.

PE

 

[chorleyjeff]

Heather, Photocolor has been around for a long time, the company who originally made it were the successors to Johnsons Photochemicals, Pip Pippard was the chemist.

Now I think they are made by Paterson. But for many years they were predominant in the UK market for their C41, RA4 and E6 kits.

It's available online at Retro, but maybe its not currently manufactured, Paterson have only just resumed B&W chemistry after their outsource manufacturer stopped making photo-chemicals in the UK.

Ian

Paterwson no longer produce RA4 or C41 developers. I e mailed them to ask and that's what they told me.
Cheers
Jeff

 

[pentaxuser]

As Jeff has confirmed, Paterson no longer does RA4 or C41 kits. Their supplier, Champion I think, moved, I believe, to Spain and there seemed to be a problem with the quantities Champion would have required Paterson to buy per consignment. Paterson's sales might have left it with stock on the shelves too long.

Pity. It was easy stuff to use and relatively cheap.

I couldn't find any mention of Photocolor on the Retro site. It seems to only deal in Tetenal kit. Most of the off the shelf kits for the low volume user have C41 blix not separate bleach and fix. Again a pity. Morco for one does the Kodak kit which has separate bleach and fix but not in small quantities.

If anyone were to find old Paterson photocolor C41 or RA4 stock for sale, he should be wary as it has to be quite old stock now.

pentaxuser

 

[ben-s]

I started doing my own C41 earlier this year. It's really easy, and my results have been good. I use the Tetenal 5 litre kit, which uses a blix, but that hasn't caused any problems yet - possibly because I don't run it to exhaustion.

I decided to get a jobo processor off e*bay, as I wanted better temperature control and auto rotation, but you don't actually need one.

It's much cheaper than having it processed commercially, and the results are just as good.
You can also take the executive decision not to charge for pushing and pulling films

 

[Bob F.]

Fotospeed, unlike Paterson's chemicals, are still around; I think I bought mine from Firstcall, but I've seen them in other online shops.

Don't have much to say as I've only just started dev and printing my own colour too (and most of that cross-processed...) and have been using Tetenal C41 and Fotospeed RA4 although I will probably buy Kodak C41 chems when the Tetenal runs out - I just wanted something simple for my first few rolls.

I already have a Jobo CPE2, so keeping the C41 at 38C is fairly straightforward. Without such equipment, a tempering bath of hot water is required to hold the working chems - possibly in an insulated container such as a picnic cooler.

Have fun, Bob.

 

[AgX]

This is why Kodak, Fuji and Agfa never released a blix for any color film product.

So, these companies recommended a C41 process which was prewet, color developer, bleach, wash, fix, wash and stabilzer.

Agfa offered within their AP70 process chemistry range (compatible with C-41) a so called `AP 70 Kit´, which used a bleach-fix.
[Aside from 37,8°C a process temperature of 30°C was advised without limitations.]

Agfa did not advise a prewet (if you mean wetting the film before employing the coulour-developer) for their CN processes, nor have I seen any hint at that in any other datasheet.

 

[Photo Engineer]

Agfa offered within their AP70 process chemistry range (compatible with C-41) a so called `AP 70 Kit´, which used a bleach-fix.
[Aside from 37,8°C a process temperature of 30°C was advised without limitations.]

Agfa did not advise a prewet (if you mean wetting the film before employing the coulour-developer) for their CN processes, nor have I seen any hint at that in any other datasheet.

I am sure that they could devise one just as we did at Kodak, but the keeping quality of a film blix is very low. It would probably be close to a one shot blix if it removed all of the silver.

OTOH, it may only have worked on Agfa films. IDK.

Here is a good blix process for C41.

Develop in C41 developer

Stop in 2% acetic acid + 10 g/l sodium sulfite (clearing stop) for 2 minutes

Wash 2 minutes

Blix in 50 g/l Potassium Ferricyanide + 200 ml /l of 60% ammonium hypo for about 5 minutes then throw this solution away.

Wash 10 minutes

Stabilize.

This is all at 100F.

That should work, as the Ferricyanide/hypo blix was one of the earliest and least stable and would never survive a deep tank replenished process.

BTW, I have not tried this with current films so I do not warrant the process. I have not done this since about 1970 or thereabouts.

PE

 

[AgX]

Tetenal state for their `fast blix´ (4min in contrast to Agfa's 10min blix) a shelf life of the working solution of 2-4 weeks.
Well, they don't state whether this is for fresh or used blix.



But what about that `prewet´ thing, PE?

 

[Photo Engineer]

Either way, at a useful pH and at a high enough concentration to blix modern C41 films from Kodak and Fuji, the lifetime of the hypo will be rather short. A good blix for fillm, using hypo, will need ammonium salts and will begin to go bad the minute the two parts are mixed. One part is an oxidant and the other is a reductant.

BTW, Kodak RA blix mixed at 2x concentration and then brought down to pH of about 4.5 (it turns orange like orange juice from the original blood red color) will make a passable blix for C41 film, but is only stable for hours.

PE

 

[Photo Engineer]

I would like to add that I spent nearly 50% of my time for over 5 years on the subject of blixing C41 films and have a patent on the topic with 2 of my co-workers. I also designed the current paper blix which is esssentially unchanged from my original formula of 10/1966.

PE

 

[AgX]

PE,

I know about your work on blixes and your knowledge is highly appreciated.

I just referred to the fact that other companies offered blix processes. Whereas that very Agfa chemistry was seemingly intended for amateur use, the Tetenal chemistry is intented for rather large volumes of working solution too, especially allowing repeated runs with blix solution.
From that I conclude that it works. The quality of such a blix-process may be another issue…


And again:
You referred to the use of a pre-wet. There is no hint at such in any type of C-41 datasheet I got.

Did I miss anything?

 

[Ian Grant]

Try this page, was listed yesterday and is still listed today. Scroll down the page. Dead Link Removed

Yes unfortunately the Champion relocation ended production of all Paterson photo-chemicals until the recent link up with Calbe for B&W chemicals. A little known fact is that the original manufacturer of Paterson chemicals was Ilford !

Ian

A
I couldn't find any mention of Photocolor on the Retro site.
pentaxuser

 

[Photo Engineer]

AgX;

I always use a prewet in a tube processor, but do not in rubber tank or tray processing.

The reason is one of tempering and of getting even development. In a tray, for example, it is easier to dunk the sheet in at once, but with a drum, there is an initial swirl pattern on dry film that is not present with wet film.

I've tried all combinations, and now feel that the stainless racks in tanks should also get a prewet based on the initial temperature shock of the relatively cold stainless hitting the developer.

A prewet certainly does no harm to the film that I have ever detected.

As for a blix for film, I have seen considerable degradation of colors due to blixes which leave in some silver. I have seen poweder blixes using sodium salts that are very weak indeed in bleaching film.

I have seen the effects of silver on grain and surprisingly it makes it worse sometimes instead of better as you might expect from experience with staining developers. I would think that the grain would be better, but it is the way the grain is distributed unevenly in dmax areas that show it up in prints.

In any event, I'm still working on this problem. It is very hard to make a stable active blix for film. It may appear to remove silver, but if the level is much above 1 or 2 milligrams per square foot, you can see it in the highlights of the print as increased grain.

Over exposure makes it worse.

I'm sorry for my comment about my experience, but I was trying to emphasize the fact that I have worked almost fruitlessly on this effort for a large portion of my life and have seen others sell these 'film blixes' when I have mixed the identical blix in the 60s or 70s and found that it just is not effective.

I have found additives that will work, but they are either toxic or expensive. For example, adding about 20 g/l of thiourea to such a blix will make it quite effective, but thiourea is a carcinogen and is banned in some states. Our efforts in this can be seen in the patent. The cost or toxicity are issues that ruled a blix out for Kodak and Fuji. As I said, I cannot speak for Agfa. But, at the start, Agfa didn't sell one either.

PE

 

[Ian Grant]

Ron, the blixs used in the best amateur C41 kits are far better than those you may have worked on for the old dunk dip, and roller transport machines for one simple reason. They aren't used to anything like their full potential capacity and they aren't replenished.

Cost is far less of an issue with Blixs in amateur kits where the major costs are the packaging, transport. So a formula un-economic for commercial use can be more appropriate for an amateur kit.

Ian

 

[Photo Engineer]

Ian;

All of the blixes that we tried were fresh mixes and used one time only for the film in question. We exposed sensitometric strips from dmin to dmax and measured the density and the retained silver.

We also measured sharpness, grain and leuco dye formation.

Color reproduction studies were done with undercut and double undercut images.

None of the blixes that we made, when used fresh, made the cut except for the ones in the patent. I see none today that offer anything new. They are all either ammonium or sodium ferric EDTA and sodium or ammonium hypo at a pH of about 6.5.

There was, at that stage, no consideration of deep tank use, roller transport or anything including cost. That came later when every possible approach came under review. So, while I appreciate the comment and understand it, you are looking at it backwards from the way we actually did the R&D.

I really do wish there was a good blix out there, but they all follow the same pattern. I have had samples of all of them including many now defunct versions. I have the original Agfa paper blix here in a packet unopened left over from early experimentation, and I just disposed of two Japanese blixes by using them for color paper, but not film.

I used to get samples of these from everywhere and everyone. All got tested for paper and film, but not in seasoned or mechanical processes as you mention. Only if they survived this first cut did they go on for machine testing. They were all compared to our own blixes and bleach then fix technology for image quality.

If any passed our test, they went to Photographic Technology for testing in the continuous machines to see how they survived in a real world situation. Most all that got through the first cut failed there. We then had to fall back to the bleach then fix situation.

I have reams of patents on bleaches and blixes and stll remember some of the hallmark numbers such as BP 991,412. ( I think I got that right)

We also studied patents on removing metals from ores to see if there was any technology there. There was, but it would not work in film. We even had special chemicals synthesized, and just before his death, Keith Stephen was working on a new silver halide solvent that might have done the job.

As far as bleaches go, we worked with quinone, persulfate, Ferric ammonium citrate and chloride, copper salts and etc. None worked well either as a bleaching or blixing agent for one reason or another.

So, the best amateur C41 kits are nothing more than things I saw over 30 years ago. I stand by this. I see nothing new here, truly I do not.

PE

 

[Discpad]

If you do not use a stop, don't rinse. Go directly into the bleach. I suggest prewet/develper/stop/bleach/wash/fix/wash/stab or prewet/developer/bleach/wash/fix/wash/stab.

A water rinse after the color developer with no stop can introduce crossover.

PE

Could you please elaborate on the wash/crossover issue? I never heard that one before; and I have a wash cycle programmed into my ATL-3 in order to prolong the life of my bleach...