View Full Version : strange colors in home processed C41

13-Mar-2013, 13:10
I recently processed my first sheet of 4x5 Portra 160 (C41) at home using the taco method and the Unicolor 1 liter kit.

I thought it had gone well but the colors are not looking right at all and I'm wondering if anyone has any suggestions on what I may have done wrong. One possibility is that I may not have washed the film properly before developing.

Perhaps I will try another test sheet and see how it turns out.

Any suggestions are welcome.



Light Guru
13-Mar-2013, 13:16
The temperature of your chemistry was probably off.

13-Mar-2013, 13:29
Hmm... yes it is also possible that the temp was off. I'm going to try again and see if I can manage the temp a little better.


Light Guru
13-Mar-2013, 13:53
Hmm... yes it is also possible that the temp was off. I'm going to try again and see if I can manage the temp a little better.


Color film developing requires VARY consistent and accurate temperatures.

Bruce Watson
13-Mar-2013, 14:13
Color film developing requires VARY consistent and accurate temperatures.

In addition, C-41 requires very consistent and, IIRC, constant, agitation. It's an agitation / temperature thing -- the chems have to diffuse through like 24 layers or so to get to the inner-most layers and develop them, without cooking the outer-most layers. In particular, if you don't hit the temperature exactly, and maintain it exactly through the process, you'll likely induce color casts that are highly resistant to correction.

The taco method is a B&W method AFAIK.

13-Mar-2013, 17:32
Hi, Bomzi,
I think your negative is probably OK and it has not been properly gamma corrected and balanced on the 3 channels . Blue dominates after the neg is inverted
I suggest download the data sheet for the film and scan the neg as a positive with no correction, then apply the reciprocal gammas and gains. After that some manual adjusting is needed.
Not an easy job, I am doing same now on 35 mm Fuji 400 and 800

Daniel Stone
13-Mar-2013, 17:50
Shadows under open-sky conditions are naturally "blue" remember, so that might be adding to your color cast issue.
Density looks good though, at least according to your scan posted here in your original post.

Getting a quality scan from the start is important, but negatives CAN(they don't always) give you more "leeway" in terms of exposure.

Just try grey balancing your scan for the street, the rest might just fall right into place.


14-Mar-2013, 03:57
Is that a scan from the negative? Heaps of ways in which that can go wrong if you're not experienced in scanning C41. Have you tried an RA4 print from it?

Peter Gomena
14-Mar-2013, 08:28
Ditto the above. Your scan is off, and most of the foreground of the shot is is shadow, which will have a deep blue to blue-cyan cast. The sunlit building will likely be very warm. You have a color temperature difference between sunlight and shadow of several thousand degrees Kelvin.

15-Mar-2013, 03:09
If you want to check that your home C41 is working properly, I suggest making a range of identical exposures on two rolls of film - I suggest using a pair of backs on a medium format camera and alternating backs while iterating through a bracketing range Make sure you have white light (e.g. strobe), all the primary colours, a full range of greys (6 stops) and some skin tones in each image. Send one to a good pro lab and do the other yourself. You can visually compare the negs, e.g. look for shadow transitions, etc. And once you've setup the lab-developed roll to print nicely to RA4, stick your home-developed film in and see how well the output matches.

15-Mar-2013, 08:32
thanks for all the advice! I will try and rescan and see if that works.

I have done a test on another sheet of film and that one seems to have come out fine. I was very careful with regulating the temp this time.


Daniel Stone
17-Mar-2013, 22:00
That looks much better.
Now, VISUALLY compare the negatives side by side on a light table, or back lit against an evenly lit surface. Look at the color of each negative. When you've become used to looking at(and printing from, optically) from well-shot/processed negatives w/ good color balance in-shot, it will become easier to 'adjust' your workflow (even if scanning) to work with film that might have a potential color shift.


Jim Andrada
18-Mar-2013, 11:48
I played with it for a while - the relative curves for each color are pretty badly messed up - I suspect issues with both exposure and development. I think it's possible to make a usable image, but I don't know the original colors so it's just a guess.

http://farm9.staticflickr.com/8107/8569757812_4b5d40f59b.jpg (http://www.flickr.com/photos/89514126@N05/8569757812/)
Test shot for collor shift updated (http://www.flickr.com/photos/89514126@N05/8569757812/) by Kirigakuresaizoh (http://www.flickr.com/people/89514126@N05/), on Flickr

19-Mar-2013, 18:38
One possibility is that I may not have washed the film properly before developing.


Hi Randhir,

I want to mention you should never wash the film before developing, this negatively impacts the process which is timed very specifically. The process has no wash before the first developer.

Perhaps it was the pre wash or less regulated temperature? ... I think there's some wiggle room with temp, though not very much.

While developer should be carefully regulated, bleach and fix temps are safe to vary, usually between 75-105f.

Pre heating is fine. I carefully stand my Paterson daylight tank in a sink with 100f water, along with the chemistry bottles.

You don't want any water drops to touch the film before the developer.

I learned about this, making final rinse with distilled water only (for no water marks), and the finger squeegee method, though not really applicable beyond medium format, from:


The Unicolor kit is decent, but if you plan to do C-41 more often, I recommend buying Kodak Flexicolor and replenishing the developer, which sounds harder than it is.

I believe the Unicolor kit is the Jobo C-41 Press Kit, which I think I heard was produced for photojournalists to process C-41 quickly in their hotel rooms.

I've also heard separate bleach / fix steps as with Kodak Flexicolor (vs. BLIX as with Unicolor), produce better negatives.

Around NYC, I think Unique Photo in NJ is the best place to obtain.

I once ordered the Fuji X-Press 5L kit from macodirect in Germany, but that is much more expensive, and of comparable quality.

According to one of the owners, LTI (the lab in NYC) uses Kodak C-41 and Fuji PRO-6 for E-6.

Sometimes negatives are hard to scan, often auto settings on scanners are not ideal, sometimes film is expired, or is over or under exposed.

I'm not sure what happened to your shot.

Keeping temperature around 100f and following the process is not rocket science, exposing a photo sometimes is closer to it :D

I usually get good results with DIY C-41. I live close to Cooper Union, if you want to discuss the process sometime, I would be happy to (PM me).

Here are two medium format home processed C-41 negatives I am particularly happy with ...