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IanMazursky
13-Jan-2010, 02:02
Hi,

I was processing some Tmax 100 4x5 and 8x10 in my PhotoTherm processor.
Usually the results are perfect with Tmax film but this last batch left a lot to be desired.
It has a brownish stain (dichroic fog?) over the film.
It looks worse at the edges and if i wipe it with my finger, it comes off a bit.

Should i be looking at anything specific in my processor or processing for the culprit?
Phototherm recommends Tmax Dev (Not RS) 1:5. I do have some RS hanging around.
Would that be worth trying and would the times be the same?

Many Thanks!
Ian

MIke Sherck
13-Jan-2010, 07:55
If it wipes off, it isn't fog. Also, "dichroic fog" isn't usually brown or muddy; iridescent is how it's often described.

What water did you use for the chemistry? Will the brown gunk wash off?

Richard M. Coda
13-Jan-2010, 08:52
I don't know what a PhotoTherm processor is, but Kodak recommends RS for TMax. I would stick with them.

Phil Hudson
13-Jan-2010, 09:33
Sorry to add another question rather then contribute an answer but how do you develop 8x10 in your phototherm? I have the 4x5 holders but have not seen the 8x10 version.

I did experience dichroic fog using Tmax developer in the Phototherm so I have always used Tmax RS since with good results and no more fog.

Maybe the local tap water is being pumped from different sources at different times of the year (they sometimes do this to assure the quality of tap water here in the UK). Perhaps that might induce the fog?

Mike1234
13-Jan-2010, 09:35
How old is the developer?

neil poulsen
13-Jan-2010, 09:51
This is exactly why Kodak recommends not using the original TMax developer for sheet film. It has to do with the surface physics of the film. I forget the details; it's been a while. If Kodak still has technical film support, you could call and ask.

nolindan
13-Jan-2010, 09:53
TMax RS is recommended by Kodak for TMax sheet film as the regular TMax developer will deposit dichroic fog on the film.

When wet dichroic fog looks like a brown sludge that can be partially wiped off. When dry it has an iridescent sheen, often looking brown by transmitted light and yellow-green by reflected light.

Change to the RS version of the developer and your problem will go away.

Keith Tapscott.
13-Jan-2010, 10:48
Is it just the regular Kodak T-Max developer that can cause dichroic-fogging, or can other brands and types of commercially available developers do so as well?
I don`t use T-Max developers, I`m just curious to know.

IanMazursky
13-Jan-2010, 11:00
Phil, The water quality here in Westchester NY is really good. We get it from the catskills i think.
I have been able to mix anything over the years with it without issue.

Ive only had this problem once or twice with Dichroic Fog on Tmax in the PT.
It went away before i could figure it out. The developer, fix and perm wash are all new.
Its so strange that this comes and goes but i also processed some 120 trix and it came out fine.
Well except for some photo flo marks but that was my fault. 1:200 accidentally turned into 1:100.

As to the 8x10 in a PT, well that is a bit of a mess.
I took a 35mm reel and cut into it to make a larger groove for the 8x10 to sit in.
I had to tape one of the ends to the spindle of the 8 reel tube.
Once the film is all the way, you have to tape the ends together or they will come out.
This will leave some AH residue that may or may not come off but im only using it to test my LVT film recorder.
It works but not well and you can only do 1 at a time safely.
I am buying a jobo atl 2200 or 2300 soon and that will take care of any remaining issues with 8x10 dev.

Regarding Tmax RS, Do you have any times for it in the PhotoTherm? I have a lot of it hanging around from a darkroom i bought out.
Would the dilutions be the same as on the box or different? PhotoTherm recommends Tmax dev at 1:5 instead of 1:4 as kodak recommends.
PhotoTherm doesn't have any times and when i called they didnt want to test it.
Any help would be appreciated.

IanMazursky
13-Jan-2010, 11:11
Hi Nicholas,
Thanks for the description of Dichroic Fog! That fits it to a T.
When dry it can also be wiped and the brown does go away but the silvery sheen remains.
I forget where i read it but a book said something about using farmers reducer to remove the stain?

Keith,
Im not sure if it happens with other developers.
Regular Tmax dev and Tmax sheet films seem to have this problem.

nolindan
13-Jan-2010, 11:33
I forget where i read it but a book said something about using farmers reducer to remove the stain?

I think that was Richard Knoppow on the Pure Silver mailing list or on the rpd usenet newsgroup.

I have never tried it, but in theory it should work (famous last words). I would use a very quick dip in rather dilute reducer.

jnantz
13-Jan-2010, 12:09
Hi Nicholas,
Thanks for the description of Dichroic Fog! That fits it to a T.
When dry it can also be wiped and the brown does go away but the silvery sheen remains.
I forget where i read it but a book said something about using farmers reducer to remove the stain?

Keith,
Im not sure if it happens with other developers.
Regular Tmax dev and Tmax sheet films seem to have this problem.

i got the fog by using regular tmax developer instead of rs
and i removed it by using farmers reducer.
it worked like a charm!

john

madmax12
13-Jan-2010, 13:04
whats farmers reducer I have the same problem happening now.

jnantz
13-Jan-2010, 13:15
i believe it is potassium ferrocyanide ( pt a ) and non hardening fixer ( pt b )

(pt a) is mixed and the film is soaked in it, refixed and then washed.
it might take a few dunks to remove the fog.

Bruce Watson
13-Jan-2010, 14:49
If Kodak still has technical film support, you could call and ask.

Of course they do: +1.800.242.2424 and extension 19 for Kodak Professional. Twelve to one they know the answer to this riddle.

jnantz
13-Jan-2010, 20:23
Of course they do: +1.800.242.2424 and extension 19 for Kodak Professional. Twelve to one they know the answer to this riddle.

LOL

in 1991 they suggested i use regular tmax developer instead of the tmax rs to process sheet film.
when i contacted them and asked them about the funny greenish metalic fog on my film
they told me there was nothing i could do about it, and the only solution was to
throw my film out and reshoot whatever was on the negatives.

paul krot at sprint systems ( sprint photo chemistry ) was the one who saved my skin.

the folks at extension more than likely will not know how to use their own product
(kodak sells farmer's reducer) to get rid of the fog.

while paul passed away many years ago, his company is still around
and it still make some of the best and easiest to use photo chemistry around.

IanMazursky
13-Jan-2010, 20:51
In my case Kodak has not had the answer in the past for rotary tube questions.
Not their fault at all but its beyond what the knowledge base has on file. They have been geared to D&D small tube and tray.
Back when i ran my wing lynch, I was on the phone with kodak almost everyday trying to figure out some painful e-6 and B&W stuff.
They were only able to quote the tech pubs back to me and some off the top of the head suggestions. Nothing firm or really useful.

One issue is that they don't have times or tables for every type of processor and chemical combo.
As an example wing lynch had a few different models, each one had a slightly different timing requirements and dilutions.

I think im just going to use up the rest of the Tmax dev tank on some 120 film i haven't processed yet and mix up an RS batch.
I hope it works, 8x10 film is to expensive to keep testing with. Has anyone tried Tmax RS dev in a Phototherm?

Phil Hudson
14-Jan-2010, 00:43
Ian,

I use RS at 1+6 and 30rpm setting for 5' 15'' although admittedly this gives me quite dense negatives. I have not done any exhaustive testing (mostly use the Phototherm for E6) but these settings are a starting point. I pre-mix the concentrates A+B and dilute from there. No problem keeping the mixed concentrate for 2-3 months in my experience.

If you arrive at different settings or times through testing please do let me know! I'm not vastly experienced in the Phototherm use for B+W but it is a great simple to use machine.

Cheers, Phil

PViapiano
14-Jan-2010, 01:14
I have a PhotoTherm but have never processed sheet film in it...but...

John Sexton has written about the dichroic fog you can get by using plain TMax dev with sheet film, and I believe he uses a Jobo rotary.

Keith Tapscott.
14-Jan-2010, 08:57
Hi Nicholas,
Thanks for the description of Dichroic Fog! That fits it to a T.
When dry it can also be wiped and the brown does go away but the silvery sheen remains.
I forget where i read it but a book said something about using farmers reducer to remove the stain?

Keith,
Im not sure if it happens with other developers.
Regular Tmax dev and Tmax sheet films seem to have this problem.It seems to me that Tetenal Ultrafin-Plus is a competitor to Kodak T-Max developer, so I was wondering if that might also cause the same problem with sheet-films.
I haven`t read about any problems with Ultrafin-Plus and I was going to suggest it as an alternative to T-Max RS.
Thanks for the reply.

IanMazursky
14-Jan-2010, 15:13
Hi Keith,
I would love to try some other developers but the PhotoTherm was designed a bit differently then a Jobo ATL.
Its not as flexible when it comes to chemistry and times. A lot is pre programmed.

PhotoTherm has a table that comes with the machine for most films but its only for Tmax dev 1:5.
Most of the times are not the standard published ones for rotary tube but they work for the combo of film, chems and times.

Phil,
Thanks for the suggestions. I need to keep the same densities in the negs that come out of the processor.
I am using them to help calibrate my LVT Rhino. The LVT is extremely sensitive to processing.
Ill try to experiment with Tmax RS soon. Hopefully i can match what i get from the regular Tmax dev.


I did some more research on the net and found that a acidic stop bath might help.
The PhotoTherm uses a water bath between the dev and fix. Maybe that could help to stop the Dichroic Fog?
Ill try to mix up some kodak indicator stop bath and reprogram the machine.
Hopefully that works.

Thanks to everyone for the suggestions.

Robert Hughes
14-Jan-2010, 20:46
But, what if I stick with Tri-X? Will I suffer from Trichroic fog? :confused:

percepts
14-Jan-2010, 20:51
But, what if I stick with Tri-X? Will I suffer from Trichroic fog? :confused:

No you'll just be very tri-ing:D

IanMazursky
14-Jan-2010, 21:59
Hi Robert,
Nope, TriX is fine. Ive processed a lot of it from the same Tmax dev tank and they are 100% OK.
Its seems to be only Tmax 100 that causes the problem.
Of course it has to be that Tmax 100 is giving me problems and thats the only film that Durst recommends for the LVT.
Some days you just cant win.

I was also thinking about what Phil said about the water quality. While our water is fantastic, i wonder if the PH changed.
The PhotoTherm uses a water bath as a stop, maybe its not acidic enough in the winter.
I should get a PH meter or find those little strips from my old chemistry sets and make a running record.

I know some of you are wondering why i don't use distilled water, the PhotoTherm requires the metals that are naturally present in tap water to run.
In the tempering chamber (a lab stir plate/heater with a stir bar), it has a number of metal wire electrodes at different heights that sense the water level.
It uses them to tell the pump when to stop pumping fluids and when the proper level of fluid is reached for the different sized drums.
I even bought one of those home water distillers off of ebay, it works but i cant use it for the PhotoTherm.

PViapiano
15-Jan-2010, 01:29
Ian...did you know that PhotoTherm will make you a new custom chip with times and temps for basically the return of your current chip plus shipping?

IanMazursky
15-Jan-2010, 02:48
PViapiano, Thanks for reminding me, i knew they could make a custom chip but i didn't know the second part.
It might be where i have to go.

I just tried using an acid stop and it didn't help so Tmax RS is next.
Im going to call PhotoTherm in the morning to see if they any more recommendations.

Sal Santamaura
15-Jan-2010, 09:15
...While our water is fantastic, i wonder if the PH changed...The latest water quality report for your supply is here:

http://nyc.gov/html/dep/pdf/wsstate08.pdf

Note that, since the Catskill/Delaware and Croton Systems are blended, your tap pH runs from 6.5 - 8, with an average around 7.2 (98.3% of delivered water comes from Catskill/Delaware).

I hope those data will keep you from having to do your own measuring. As a former New Rochellean, I've certainly missed the water quality since leaving there for southern California 33 years ago. Here, we simply describe ours as "crunchy," just like the air. :)

Brian Ellis
15-Jan-2010, 10:12
Is it just the regular Kodak T-Max developer that can cause dichroic-fogging, or can other brands and types of commercially available developers do so as well?
I don`t use T-Max developers, I`m just curious to know.

I used D76 1-1 almost exclusively with TMax 100 and never had any fogging or similar problems. Also used Rodinal once in a while and another brand - LPN? LFN? - something like that - without a problem. John Sexton uses TMax RS but IIRC he dilutes it differently than Kodak suggests or does something else differently, I don't recall exactly what.