Pyro for thick emulsion film?

[Jay DeFehr]

Armando,

It seems you can be fairly certain the increased agitation is responsible for the increased development, but what we still don't know is how different from your more developed negative one developed to the same contrast at lower speed would be. What your test seems to show is that the two rotation speeds lie within the range in which increased rotation speed results in increased development, and that the faster speed doesn't cause streaks or other defects including increased general stain, even when developed to a higher contrast. None of these were foregone conclusions, so your test was not a wasted effort. It might very well be the case that development at the higher rotation speed for a shorter duration produces better results than lower rotation speed for a longer duration, but your test doesn't show this, because the two films were developed for the same time instead of to the same contrast, which is a more demanding test.

510-Pyro was designed for just the scenario you've tested. The ascorbic acid content was optimized for very vigorous agitation and development to high contrast without producing significant general stain. I think you'll get different results from the same test using Pyrocat HD.

[onnect17]

Jay,
I scan most of the negatives so I'm OK with densities above 3.0. Also the brown stain give me differents contrast levels in each channel if scanning in color mode.

I think I will use a dilution of 1:200 next time for 510-pyro. Something tells me the developer is very active with agitation. I'll let you know.

In the meantime, here's a one of the shots developed at high agitation (no part of control strip, of course).

[fridrik]

A lot of information here, thanks!
I would like to ask then, for grade paper does the stain work similarly as toning the negative in selenium? Also can you explain what is the effect that produces the stain, does it affect longevity of the negative?

[Cor]

A lot of information here, thanks!
I would like to ask then, for grade paper does the stain work similarly as toning the negative in selenium? Also can you explain what is the effect that produces the stain, does it affect longevity of the negative?

Indeed the stain works as added density when you switch to a graded paper, another benefit of the Pyro stain is that you obtain a dual purpose negative: I print my 8*10 negatives both as silver gelatine print and as pure Platinum prints, because under UV the stain acts as extra density, density needed in alt. photo processes.

As far as I know the stain is as archival as the silver image, but perhaps other people have more definitive information.

Best,

Cor

[Jay DeFehr]

Very nice, Armando!

[Drew Wiley]

Greg - I found tweaking pyro with amidol a bit unpredictable, simply because the action of this chemical is much more fussy than when used as a print developer, and
miniscule differences in quality or freshness had a significant effect. Even when I
used the best stuff I could find it was a bit of a crap shoot.

[Greg Blank]

Greg - I found tweaking pyro with amidol a bit unpredictable, simply because the action of this chemical is much more fussy than when used as a print developer, and
miniscule differences in quality or freshness had a significant effect. Even when I
used the best stuff I could find it was a bit of a crap shoot.

I honestly have never seen that sort of issue, been using the same batch of amidol for over ten years, when I run out in 2015 or so, maybe I will.

[onnect17]

Very nice, Armando!

Thanks Jay,
Here's another shot, this one developed in Pyrocat-HD at high speed for 10 min ended up with a lower max density (compared to around 5 min for 510-pyro)
The 1:200 test still pending.

[bobherbst]

Pyro image stain is more archival than the silver. Attached are two images for illustration. The first is a scan of a negative on which virtually all of the silver is gone. The negative was shot around 1910, is on nitrocellulose film, and was developed in pyro. As you can see, there is virtually no silver left - only stain. The second image is how this negative prints on Azo grade 2.

As far as I know the stain is as archival as the silver image, but perhaps other people have more definitive information.

Best,

Cor

[Ken Lee]

That's a very interesting observation Bob - Thanks for sharing !