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When processing reversal as a negative how much should you over-expose?


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#1 grantsmith

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Posted 24 November 2006 - 01:15 PM

Hi there,

I have some reversal (tri x and quartzchrome) which I want to process at home using d76.

How much should I over-expose by to get the best results? One stop?

Also, if anyone has any recomendations for the tri-x development time and temperature that would be great.

Thanks
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#2 James Erd

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Posted 24 November 2006 - 02:37 PM

Hi there,

I have some reversal (tri x and quartzchrome) which I want to process at home using d76.

How much should I over-expose by to get the best results? One stop?

Also, if anyone has any recomendations for the tri-x development time and temperature that would be great.

Thanks


I think it would be around 1-2 stops based on having gone the other route ( neg to reversal ). At my U we used to develop T-max 100 as reversal and the ASA turned out to be around 25 using our chems. Kodak's kit recommended 50 ASA if I recall correctly. We found our ASA by doing a good bit of shooting and a fair amount of testing. On the other hand Tri-X negative film is usually 400 ASA ( if memory serves ) but I always shot it a little slower by about 1/3 of a stop. I'm not familiar with quartzchrome, but I can look up the times and temps for the Tri-X and probably get some better recommendations.

Edited by James Erd, 24 November 2006 - 02:39 PM.

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#3 grantsmith

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Posted 24 November 2006 - 05:40 PM

Thanks James,

The Quartzchrome is asa 50.

Thats really cool. I had no idea that it was possible to develop a neg as reversal. I think I will have a go at trying that also. Much appreciated!
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#4 James Erd

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Posted 24 November 2006 - 07:35 PM

Thanks James,

The Quartzchrome is asa 50.

Thats really cool. I had no idea that it was possible to develop a neg as reversal. I think I will have a go at trying that also. Much appreciated!


I see from your other posts that you do your own processing. If you like I'll send the formulas for the chemistry I use.

James
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#5 grantsmith

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Posted 25 November 2006 - 02:21 PM

That would be great thanks James,

Cheers
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#6 Robert Hughes

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Posted 25 November 2006 - 02:34 PM

From the Kodak website on Plus X:

Plus-X 7265 Technical Specs

"Negative Processing
"Although designed for reversal processing, this film is capable of yielding useful negative images or conventional quality and contrast if developed in a developer such as KODAK Developer D-96 and them fixed. When a developer of this type is used, the speed is not more than 1- 1/2 to 1- 2/3 that is normally obtained in reversal processing (using KODAK B&W Reversal First Developer and Replenisher (D-94A)).

"If negatives are required, it is preferable to use films designed for that purpose."

From my experience, that means that 100 ASA reversal film processed as negative has an effective sensitivity of about 50 ASA.

I home process b&w negative film in D76, stop with dilute vinegar, fix in rapid fixer, wash and dry.

Edited by Robert Hughes, 25 November 2006 - 02:37 PM.

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#7 James Erd

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Posted 25 November 2006 - 05:39 PM

From the Kodak website on Plus X:

Plus-X 7265 Technical Specs

"Negative Processing
"Although designed for reversal processing, this film is capable of yielding useful negative images or conventional quality and contrast if developed in a developer such as KODAK Developer D-96 and them fixed. When a developer of this type is used, the speed is not more than 1- 1/2 to 1- 2/3 that is normally obtained in reversal processing (using KODAK B&W Reversal First Developer and Replenisher (D-94A)).

"If negatives are required, it is preferable to use films designed for that purpose."

From my experience, that means that 100 ASA reversal film processed as negative has an effective sensitivity of about 50 ASA.

I home process b&w negative film in D76, stop with dilute vinegar, fix in rapid fixer, wash and dry.


Kodak's recommendations not withstanding, the watchword of home processing is "Your millage may vary" but that really is one of the nice things about hand processing. You control the process based on your own esthetic judgment. The results are dependent on time, temperature, PH, variations in the chemistry and the subtle ways that agitation varies from person to person and tank to tank.

Some times the choice of processing equipment makes a huge difference. The Lomo tank has a more classic agitation scheme, where the film is in contact with the chemistry throughout the process and agitation is intermittent. The Morse G3 however, is reel to reel and agitation is continuous but the film is only exposed to fresh chemistry as it passes from reel to reel. With such huge differences in the equipment, manufacturer's recommendations for exposure and processing are best used as a guide, and the final judgement should be that of the filmmaker. In the end if it doesn't look rite, it isn't.

D76 is a great developer. It's flexible, predictable and convenient. What more could you ask for? It's important to have that predictability when you need it, especially if you are doing work for some one else, but experimentation is also very rewarding. Unfortunately film isn't cheap when you are shooting 100' at a time. Almost everything I know about processing movie film comes from my background in still photography. It was never a big deal to shoot a roll of film and experiment with alternative processing, because we were only burning up about 5' of film at a time.

These days to keep the cost down I shoot about five or ten fen of film in my bolex to keep cost down. When I feel I have some thing that looks good I try it with 50' or 100'. I keep track of the results for future use, wether or not I like the result.



That would be great thanks James,

Cheers


Give me a few days. Most of my formulas are in an old lab index, so I have to transcribe them and I type very slowly.
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