Now we know.

David M

Well-Known Member
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The transmitted versus reflected light division is not new. We’ve all seen transparencies and viewed projected images. (A projection screen does not absorb light as a print does, so it functions as an emitter.)
Did we then say that there were two branches in photography?
A very competent friend one devised a demonstration. He rigged up a viewing box where one side held a print and the other a light box, both of which could be varied. By manipulating these, he could make a viewer decide that either side was either a transparency or a print.

I see we have defaulted to the Forum’s favourite topic: Magic Developers. Could we have a separate section for Angels on a Pin, please?
 

thronobulax

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Registered User
While I've not used D-23, I have tried many other films and developers, including Perceptol at 1+1 and 1+3. While a lot of them shoulder off, it's usually at a higher density, and with sagging low values (a classic "S"), thus only slightly reducing the need for darkroom heroics when printing. The curve of Delta 100 in Atomal is very linear for low values and changes slope at just the right point to match paper's reflective range.

The Web site from which I grabbed that plot shows characteristic curves for many film-developer combinations


which can be interactively selected. Some have complained that its images are not well scanned, but I find the curves more useful than any screen-displayed image.

Most interesting, thanks!
 

Sal Santamaura

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Registered User
...this is a revised form of Atomal as the original developing agent went out of production, it had an industrial use outside photography...
An update. I've just developed some Delta 100 in the current ADOX ATOMAL 49, and included "zone" testing as part of this batch. I can confirm that the characteristic curve included in post #15 above was duplicated exactly, so any reformulation had no effect on at least that aspect of developer performance.
 

David M

Well-Known Member
Registered User

Another view on developing film, from our Mr Karchel. I found it encouraging.
 
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