Tetenal E6, yellow cast

[BMbikerider]

BMbikerider, the information you have presented is quite brief and indicative for people who have a good experience with the color reversible process.
Do you have a more complete overview of E6 processing errors?
In cinematography there is something similar cine color slides process VNF-1:
Effects of Mechanical & Chemical Variations in Process VNF-1
http://www.kodak.com/KodakGCG/uploa..._en_motion_support_processing_h2412_h2412.pdf
Here are graphs of densities based on time, temperature, substance concentration, impurities.
In connection with your highlighted phrase, the increased yellow color is due to the increased ph to the color revelator - is presented at page 12.9.
The yellow color increased due to the lower temperature of the color revelator is not confirmed and does not seem logical.
When it lowers a temperature I do not see how to increase density to color development?
Perhaps the text has some fragmentation.

George

Sorry no I don't. I have not processed E6 for years now but when I did, I never ever had a problem with colour casts except as I said previously with one roll of Velvia which also had heavy yellow cast. I actually put that down as an error by myself. I have never looked into the technicalities of the process, but just trusted the chemical and film manufacturers settings and they have nearly always been OK with me. That text I copied over was complete and nothing was missed out, however it did not specify what manufacturer(s) chemicals were being quoted for the fault analysis.

I can fully understand the 'low temperature' reasoning for the yellow colour casts because I believe the different colour layers develop at different rates. So if a 2nd development time is suggested at 38C of 6 minutes but the temp is only shall we say 36-37 the yellow layer will possibly be developed more rapidly than say either of the other two thereby giving the yellow more prominence in the colour. It only takes a little temp shift to change things dramatically, hence the need for accurate measurments of the temp. At most, a deviation of .25 of a degree.

Even with C41 which I use more regularly now, if the development stage is not spot on, with under development you get weak colours with a bias and with over development the negative is dense and the colours which can be drawn as a graph with the lines representing the 3 colours running parallel If the film is over developed you will get what are know as 'crossed curves' where one colour line intersects one or both of the other two curves and getting a good print is neigh on impossible.

Over or under exposure, but with accurate development will not give this problem, only thin or dense images on the film.

The last E6 I processed if I remember correctly was one sold under the Rollei name and apart from being quite grainy, I never had a problem. The colours were always well saturated and clear, however another photographic forum (now closed down) had several reports of 'odd' colour casts with this film including yellow which were never fully explained. Perhaps some films are more sensitive to temperature changes than others.

I do believe that the Tetenal kits used to come with a warning that some plastic measuring beakers could absorb certain chemicals, which if the beakers not segregated and always used for the same chemical, this could leach back into a new mix and cause problems. I got around this by buying laboratory glass beakers and always washed them out thoroughly after each session.

 

[georgegrosu]

BMbikerider, we need to clarify the things.
The cine process requirements are much higher than for a home-made process.
If you carefully look at the graphs from the VNF - 1 process it is seen that the maximum variations encountered go to 0.15 - 0.25 density.
These visual variations, at the amateur level, are noticeable very little.
In connection with your explanation of yellow growth when the temperature of the color developer decreases I say the following:
- In any developer, when temperature decreases, density / densitys will decrease;
- your explanation „the temp is only shall we say 36-37 the yellow layer will possibly be developed more rapidly than say either of the other two thereby giving the yellow more prominence in the colour.
I do not agree because:
1. Does not write anywhere in the original text that the densities decrease, and on the yellow the decrease is the lowest and gives the feeling of the dominant yellow.
2. Tell that if the color of the developer drops to 36-37 ° C, the yellow layer will develop faster than the other layers.
The process of development is a process driven by the diffusion of components.
When the temperature of the developer decreases, the diffusion of the components is reduced and implicitly the resulting densities will be smaller.
Store the color balance of the film.
When crossing the color curves occurs, the causes are of a chemical nature.
- I was thinking maybe it is a text error (initially).
If instead of lowering temperature of color developer was the black-white developer, it could make little sense to me.
There is a given amount of photosensitive halide in the film.
In the black white developer, a lower amount of exposed halide is developed, leaving a larger amount of undeveloped halide for the color developer.
The color developer will form more dye (density).
It can be considered that in black-white development due to lower temperature, the first layer of blue-sensitive emulsion to be influenced more than the other two layers of emulsion.
This work will lead to a lower development of the first blue emulsion layer in the black white developer.
There will be more undeveloped halide in the first emulsion layer, which in the color development phase will form more yellow dye.
Sorry for my English.

George

 

[thuggins]

The last E6 I processed if I remember correctly was one sold under the Rollei name and apart from being quite grainy, I never had a problem. The colours were always well saturated and clear, however another photographic forum (now closed down) had several reports of 'odd' colour casts with this film including yellow which were never fully explained. Perhaps some films are more sensitive to temperature changes than others.

I have read that the Rollei film is the same as what Lomo is selling. It was apparently made for high altitude photography so it has a yellow cast to compensate for the blue light. It is grainy and the colors are noticeably shifted but it has an interesting retro look.

 

[thuggins]

Roll #8 came out fine, and the chemicals are just over two weeks old. I'm going to try for 10 rolls off of a single batch of chemicals.

 

[thuggins]

Roll #10 is still wet, but it looks great. The chemicals are just over three weeks old.

Even with shipping and handling for the Tetenal kit, at 10 rolls per batch it comes out to about $1.60/roll. Considering that this last one looks as good as the first, I suspect that you could get out a couple more rolls, just extending the times out proportionally.

 

[Rudeofus]

- your explanation „the temp is only shall we say 36-37 the yellow layer will possibly be developed more rapidly than say either of the other two thereby giving the yellow more prominence in the colour.
[...]
There is a given amount of photosensitive halide in the film.
In the black white developer, a lower amount of exposed halide is developed, leaving a larger amount of undeveloped halide for the color developer.
The color developer will form more dye (density).

There is more to E6 CD than just "develops all the silver ions left by FD and forms dye". As you know, there is a competitive coupler (Citrazinic Acid) in E6 CD, there quite a bit of Sulfite, there may be similar stuff embedded in the emulsion, and all these react with oxidized CD-3 at different speeds and with different temperature dependencies. Oxidized CD-3 diffusion speed into neighboring layers is also temperature dependent. It is very hard to predict how film will respond to temperature changes in CD phase, and there's a good chance that different emulsions at different age and storage will behave differently.

 

[georgegrosu]

Rudeofus,
With my poor English allow me to make a few remarks:
1. I do not understand why do you appreciate that in the first black white developer does the less silver halide from the emulsion develop than in the color developer?
I think the first developer will develop silver halide microcrystals that have been exposed and contain development centers, resulting a silver metallic granules.
If it is a day scene, exposure will be more consistent and more silver metallic granules will form.
If it is a night scene, the exposure will be weaker and fewer silver metallic beads will form.
The development black and white must form a sufficient black, which in the color development phase will lead to the formation of a normal white.
2. Discussions about the different reaction speeds on emulsion layers are complicated and seem to forget what we left off.
When a temperature drops a density can increase?
3. I totally agree with you that the developmental behavior of a film depends on:
- how the film is made;
- Changing physical parameters (time, temperature);
- the age of the film;
- how it was preserved.

George

 

[thuggins]

Based on my "vast" experience of ten rolls thru this kit, I'm guessing that you would have to be fairly careless with the times and temperatures to get a visible problem with the results. I've got a water bath and do try to manage the temperature, but it is not some fancy, automatic thermostat controlled thingy so the temperature drifts a degree or two during processing. That doesn't even include the fact that my two thermometers can disagree by more than one degree. The same with time. I use a standard, stainless steel tank so there is time involved with filling and emptying it, turning the timer off and on, etc.