E6 development troubleshooting, slight cyan cast

Hello

I decided to give E6 development at home a try and mixed some of the E6 first developer and colour developer from (there was a url link here which no longer exists) by @stefan4u. Since pH is critical in colour processing, I've also acquired a cheap pH meter. I also had to mix some pH buffers for calibration purposes and these had pH values of 9,5 and 12, for the FD and CD respectively. I had them measured by a lab and the pH 12 one seemed to be rather off (<12), something that I attributed to my NaOH being impure. To be honest, I don't know how well calibrated their pH meter is... Anyway, I mixed these two developers and for both of them I had to correct their alkalinity with some NaOH solution. In hindsight, I should have written down how much NaOH I added, but it was ~1g for the FD and >1g for the CD (for 500ml batches).

Being my first try, I only shot few test frames of Agfaphoto CT Precisa 100. I followed the Tetenal E6 kit instructions for the most part (FD, CD times and agitation pattern), but used a well aerated C41 bleach I already had and a scratch mixed pH 6,5 fixer (sodium thiosulfate + ammonium chloride based). The times for both bleach and fixer were 10' with generous agitation. Between the FD and CD, and CD and bleach, 5 water changes were made with vigorous agitation. The film reel was exposed to light from both sides after the first wash.

Anyway, the result isn't bad for a first try, but IMHO there's room for improvement. In the sample picture below, the gray card looks wrong. It has a fair bit more blue and also a bit more green than it should.



Dmax also has some strong blue-cyan cast, but other commercially processed films I have also have some kind of cast. So, what could be the cause? Is my CD more alkaline than it should? Should I try adding a small amount of acid?

I have seen it posted various places that the Agfa film is Provia. If that is the case, Provia is well known for a cold blue cast; there is an active discussion on that here now.

From the look of that image, the problem is more than a color shift. That image looks slightly faded or fogged. It looks a bit like the fogging that occurs with a folder that has a pin hole in the bellows. Maybe it is the camera you used, but I'm used to Provia being tack sharp. Cold and blue, but tack sharp.

thuggins said:

I have seen it posted various places that the Agfa film is Provia. If that is the case, Provia is well known for a cold blue cast; there is an active discussion on that here now.

From the look of that image, the problem is more than a color shift. That image looks slightly faded or fogged. It looks a bit like the fogging that occurs with a folder that has a pin hole in the bellows. Maybe it is the camera you used, but I'm used to Provia being tack sharp. Cold and blue, but tack sharp.

Click to expand...

I'm honestly surprised that you found them faded or fogged, because I can't spot any sign of such a thing. There are no signs of light leaks either. Also keep in mind that these are unmanipulated scans of the slides, which are tack sharp as you said, when viewed with a loupe.

Anyway I've searched the technical literature from Fuji, Kodak and Tetenal and, to answer my own questions, there are two possible causes for this cast - crossover* problem. First of all, both the FD and CD have slightly higher pH than they should, about 0,1 unit. A CD with higher pH can shift the colour balance to green. That alone can't explain the blue - cyan cast though. A blue cast is a sign of using less (or no) developer starter for the FD. The starter provides various halides to the developer. I added both KBr and KI to the FD, but adding a bit more KI could be the solution to this problem. Iodide mostly acts on the top layer and adding more could shift the colour balance to yellow. Less would shift it to blue.

* Yes, careful examination of gray card shots from different exposure levels reveals that a mostly cyan cast at dark to middle tones becomes a warm cast at light tones. This is confirmed by density readings from the scanner.

As the image looks, it seems like a process issue.
A gray plus color scale would have helped determine the failure.
I only know the documentation for cine films.
Sure, we're talking about different films.
But it is more than nothing.
Here, the presentation is comprehensive enough to clarify you with a process issue.
Look at page 12-9. Figure 12-5 Effects of Time, Temperature and pH Variations-7240 Film in Process VNF-1 Color Developer.
http://www.kodak.com/KodakGCG/uploa..._en_motion_support_processing_h2412_h2412.pdf
In film processing there are two things you need to trust:
- chemicals + weighing and preparation of the solution;
- test stripe (test).

George

George, yes, a test target with a gray + colour scale would be better, but lacking this I have to improvise. The documentation for the E6 process can still be found on the web. The Z-119 manuals from Kodak can be found (among many other interesting manuals) here (scroll down to "Process E-6 Manual"). Fuji's relevant document is here. My problem can be described by the chart on page 15-4 in Z-119-15 and on page 93/111 of the Fuji document.

For the most part, I trust my chemicals, except for some that might be a bit dodgy, but probably usable. I'm especially worried about anything highly hygroscopic, but I do my best to store everything as best as I can. My scale is ok for the task, but pH measurements and meter calibration is a source of potential errors.

Thanks for the reply.

Anon Ymous, you can use a color + gray scale that you do.
And you will always report to her.
What I see in your picture seems different to me to the fault on the Z-119 manuals - FIRST DEVELOPER-STARTER Chart 3.
If you look at your image through a yellow or orange filter, the image becomes normal?

George

An orange or yellow filter distorts the colour balance way too much. It's a fairly small cast, so this kind of filtration over-corrects things. Also keep in mind that different monitors can make the same photograph look very different both in terms of contrast and colour reproduction. In any case, the density readings from the scanner also suggest this kind of cast and crossover.

Anon Ymous said:

I'm honestly surprised that you found them faded or fogged, because I can't spot any sign of such a thing. There are no signs of light leaks either. Also keep in mind that these are unmanipulated scans of the slides, which are tack sharp as you said, when viewed with a loupe.

Click to expand...

It might be handy if you were to upload an image that looks like the actual slide. The image you uploaded looks like a poor quality scan of a print made from a consumer grade C-41 film that came from a Walmart minilab. It doesn't look at all like any "proper" Provia transparency I've ever seen.

I'm certainly no expert in this area, but I have used the Tetenal kit a number of times now for Fuji, Kodak and Lomo E6 films. They have all come out just as I would expect from a top quality pro lab. The chemicals are (usually) mixed in distilled water, but the washes are always with tap water. I just follow the instructions as close as practical and have never had any need or desire to check the pH.

When I said a color filter, I was thinking about the substractive filters used to make color photos 40-50 years ago.
In the set are the 3 substractive colors (yellow, purple and azure) with 11 increasing density filters from 05 (0.05 density) to 99 (0.99 density).
Sorry for misunderstanding.
My English is not great.
https://picclick.es/Original-ORWO-Color-Kopier-Filter-7-x-322411171618.html

George

georgegrosu said:

When I said a color filter, I was thinking about the substractive filters used to make color photos 40-50 years ago...

Click to expand...

Oh, I see what you mean... that would be handy, but I don't have any of these.

Anon Ymous, if you do not have the color filters you can do this with the filters in PhotoShop and you look at your film.
Change filter color and filter concentration until you get the best image quality.
The point is to see if you have color debalans.
That is, if the three color curves intersect or not.

George

I've done so and the gray card becomes neutral when adding yellow (practically removes blue) and removing cyan (removes blue and green) when in cmyk mode.

Anon Ymous, the hardest test for a color film is to reproduce correctly all gray tones.
From white, light gray to black.
You tell me about that reference gray (photo) is OK with filter correction.
The other gray tones do you appreciate?
It is good to have all the tones of gray so when they say to you alone where the problem is.
With a single gray point, it is not possible to completely characterize a processing process.

George

The test shots also included gray card shots at different exposure levels. These, combined with Dmin, the black end caps of the film cassettes and the white paper can give some data points for plotting a characteristic curve, which I've done. The spacing between most of these data points at the X axis isn't accurate (except for 2 of them), but is reasonably close. In any case, this is the curve:



This shows the cast and crossover that I'm talking about and is very close to what you'd expect from too low FD starter used (mostly too low KI content). The slightly elevated CD pH affects to a lesser extent the colour balance. The CD has wider tolerance anyway.

Anon Ymous, you worked with this chart.
Dmax is missing from the graph.
For caracterisasion a film processing there are two very important things:
- D0;
- DMax.
If the minimum and maximum densities are good is sure that the other densities will be placed correctly on the curve.
For a color film the maximum density should be over 2.7 - 3.0.
If the maximum density is below 2.5, the projected image will appear rather washed out.
At you, the contrast on the yellow layer is smaller than on purple and cyan.
The image of you shows a color debalans (intersecting curves), ie yellow in white and indigo in black.

George

Dmax is missing because the density readings fluctuated too much between different points of the same film leader. Scanner can't cope with that much density and the readings are just noise. Dmax is a bit thinner than commercially processed samples I have, but a higher than normal FD pH can cause this. Possible Dmax values are probably above 2,7, but below 3. Dmax isn't neutral, shows a blue - green cast, but it shouldn't necessarily be neutral. From what I've seen at various datasheets, Dmax isn't neutral.

Anon Ymous, I explained to you how I stand with diplomacy.
l tell you something that I learned from my first boss.
It asked me to do something my boss.
After a while he asked me you did that?
I started telling him I was there, like ...
The boss asks me again, did you do it?
Then I understood how important it is to be concise and to assume everything you did.
Explanations have no value.
That's how it is with you.
Okay, you do not have a densitometer to read the film densities.
You can use your eyes.
Put your film alongside a film developed in a minilab on a white monitor.
Your film (Dmax) is "slightly more open," as you say.
It does not tell me exactly anything.
Put a 0.30 grayscale or a negative b&w without image (has a density ~ 0.25) and look at Dmax.
When Dmax in your film + filters approaches Dmax from the film developed in a minilab, you determine how much you are lower than normal development.
In relation to the maximum densities, I'm sure to say that there are films that have densities over 3.
I saw this in WinDense (http://www.windense.com/) in 1997.
Maximum density values are not equal, but film curves do not intersect like you.
You have to get maximum normal densities, and then you will determine if you modify something at the developer.
I would shorten the time in the first developer to increase Dmax.

George