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7231 plus X negative processed in reversal


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#1 Richardson Leao

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Posted 09 May 2006 - 12:37 AM

I suppose that is a pretty dum question, but I can process 7231 plus X negative in reversal right? What is the difference between 7231 and 7265 plus X, is that only the film base?

thanks!
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#2 John Pytlak RIP

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Posted 09 May 2006 - 07:56 AM

I suppose that is a pretty dum question, but I can process 7231 plus X negative in reversal right? What is the difference between 7231 and 7265 plus X, is that only the film base?

thanks!


Although 7231 and 7265 share the name "Plus-X", they are NOT the same formulation:

http://www.kodak.com....1.4.4.10&lc=en

Processing 7231 in a B&W reversal process may yield unpredictable results.
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#3 Leo Anthony Vale

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Posted 09 May 2006 - 01:43 PM

I suppose that is a pretty dum question, but I can process 7231 plus X negative in reversal right? What is the difference between 7231 and 7265 plus X, is that only the film base?

thanks!


---I tried this ages ago while in school.

Negative emulsions are thicker than reversal emulsions, thus the film did not dry properly in the revesal processing, leaving water marks and ferrotyping.

In reversal processing, the exposed halides are process and that silver image is bleached out.
The remaining unexposed halides are then exposed and processed, yeilding the positive image.

With the PXN, the camera exposure did not expose all that much of the silver, after bleaching and second development there was a lot of excess silver fog, giving a very dense image with no actual whites/clear area.

In addition there were very strong edge effects beteen light and dark areas.
It looked like a positive with an unsharp density mask, but with water spots.

---LV
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#4 Richardson Leao

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Posted 11 May 2006 - 07:35 PM

I recentely developed orwo negative as reversal with no problems, they turn out great, also, the fomapans are good when processed reversal. With photo films, the ilford also works when reversed. What would be the problem with the kodak? Thanks again.

---I tried this ages ago while in school.

Negative emulsions are thicker than reversal emulsions, thus the film did not dry properly in the revesal processing, leaving water marks and ferrotyping.

In reversal processing, the exposed halides are process and that silver image is bleached out.
The remaining unexposed halides are then exposed and processed, yeilding the positive image.

With the PXN, the camera exposure did not expose all that much of the silver, after bleaching and second development there was a lot of excess silver fog, giving a very dense image with no actual whites/clear area.

In addition there were very strong edge effects beteen light and dark areas.
It looked like a positive with an unsharp density mask, but with water spots.

---LV


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#5 Charles MacDonald

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Posted 11 May 2006 - 07:40 PM

I recentely developed orwo negative as reversal with no problems, they turn out great, also, the fomapans are good when processed reversal. With photo films, the ilford also works when reversed. What would be the problem with the kodak? Thanks again.

The FOMA r-100 is apprenetly ONLY for reversal, they use a silver anti-halo layer which will not be cheared if it is processed as a negative. Many films do have a different effective speed when reversed. I wonder if that is the problem? Of course the Dmax may not be as high in some cases.
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Metropolis Post

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