Tetenal E6 3-bath kit contrast

[Chris Bronson]

I am using the Tetenal E6 3-bath kit with a Jobo CPE2plus for a few months now. My results are acceptable but shadows are generally too dense and details in low-light areas are becoming difficult to recover when scanning. This leads to my question: is there a way to reduce/control the contrast of a film during the E6 development process?

To illustrate the phenomenon here are the development curves I am getting using Provia 100F. The 3 plain lines are for the Tetenal E6 3-bath kit at 3 different FD times with the Jobo CPE2plus. The dashed line is for the same film developed at a professional lab using Kodak E6 chemistry.



The process used at the lab is much more lighter in the low-light areas and is substantially increasing the film's usable latitude. How could I achieve similar results with the Tetenal E6 3-bath kit?

Thanks in advance for your advice.

Chris

 

[albertphot]

You could try to overexpose your film and shorten the FD,( like a B&W film!).
Question: is your temp. 38,0°C? this could also be to hot and increase contrast.

 

[Chris Bronson]

Thanks for your suggestion. Unfortunatly, adding exposure and reducing the FD time won't reduce much the slope of the curve. Fyi, the temperatures of the chemicals are all kept within E6 process tolerances.

 

[Rudeofus]

I see your lab processed film max out at D=2.1 or so, are you sure that is correct and if yes, are you sure that's what you want?

 

[Chris Bronson]

The step chart used for the Kodak E6 test was limited to -1.9 log exposure. Dmax is around 2.6.

 

[pukalo]

You should see absolutely no diffrence between the lab processed (probably Kodak chemistry) and the Tetenal chemistry. I use both, hand developed in a Paterson tank, and can vouch for the fact that the end results are identical. That is, perfect colors and exposure. The only sub par chemistry is the Arista, which gives very vibrant colors, but too much saturation for people pics (bad skin tones). The culprit is almost certainly your JOBO equipment. Search the net and you will find similar complaints about underdevelopment with JOBO equipment. I suggest trying 1 run hand developed in a Paterson tank at the correct temperature. If it comes out fine, you will have confirmed that your JOBO is at fault.

 

[Chris Bronson]

Thank you pukalo for your input. My question was: is there a way to reduce/control the contrast of a film during the E6 development process?

Edit: Issue solved. E6 contrast can indeed be reduced by using citrazinic acid and sodium hydroxide in the CD. For further information read the following APUG thread:

(there was a url link here which no longer exists)

 

[pukalo]

I wouldnt mess with that. You should be getting good/normal contast using the Tetenal kit, UNLESS you are over using the chemsitry or using chemistry that is too old. Mix up and use fresh chemistry, and discard it if not used within the week or 10 days at most. And stay within the capacity limits stated (12 rolls max/per liter). I have run the Tetenal 5L kit to 60 rolls, irs advertised capacity and found it to be true/give good results up to the 60th roll. But I did all this within a 3-4 week period, mixing up 1 liter at a time.
In fact, the Kodak chemistry (FD) builds up contast much faster - 30 rolls max out of the 5L kit. And between 25-30 rolls and I had to run only lower contast slide films like Astia and EC200. Now, in a constantly replenished lab system, not an issue, but limiting for home users.

 

[Photo Engineer]

The Dmax of Ektachrome film should be about 3.0!

This indicates to me that the "check" is low in contrast and Dmax.

But, if you insist that the Tetenal kit is too high in contrast/Dmax, then I would look at the level of Citrazinic acid.

Well seasoned E6 developer should be bright green. If it is not, then the level of CZA is low.

PE

 

[Chris Bronson]

Thank you PE.

Update: According to Tetenal their E6 process is slightly more contrasty than Kodak's. This choice was made at a time when slides were mainly used for projection or scanned on PMT devices with high Dmax. Most users were satisfied with the results and the chemical recipe was kept until nowadays. In fact, Tetenal was selling a CZA based contrast reducer for its E6 process to adress the issue, but the product was discontinued due to low demand.

 

[Photo Engineer]

Chris;

IMHO, the Tetenal looks more normal than your reference slide. That Dmax is really low. Do the blacks in your slides look gray? Do the slides look milky? If so, then something is wrong with that reference process.

PE

 

[nworth]

The Tetnal 3 bath E-6 process uses a blix, rather than separate bleach and fix. As PE has pointed out several times, films do not do well with blix. I have used this kit, and I found that the transparencies consistently came out darker and somewhat more contrasty than those processed in the Kodak six solution kit. That effect was probably due to retained silver.