How does "staning" developers like Pyrocat HD or others effect printing?

[stradibarrius]

When you use a staining developer like Pyrocat HD how does it effect print-ability. Does the stain filter some of the colors from the enlarger light or from the scanner for that matter?

[Kirk Gittings]

Not sure how to answer that scientifically (been a long day) except to say that with multi-grade papers you get better detail in the highlights and generally I prefer them for scanning too as I get a more linear neg. with good shadow and highlight detail. That is with FP4+.

[Steve Sherman]

When you use a staining developer like Pyrocat HD how does it effect print-ability. Does the stain filter some of the colors from the enlarger light or from the scanner for that matter?

A staining developer adds stain (density) proportionally to the exposed negative. The more highly sensitized areas of the image gain and accept more stain.

The stain has two major positives, first, the film will require less time in solution which directly impacts the sharpness or accutance of the negative and resulting print, the grain is masked to a degree which effectively produces sharper appearing prints.

Second, the stain will increase the effective contrast index of a given negative when the light source is Ultra Violet, used primarily in alternative processes which normally requires a more contrasty negative. Pyro based negatives have the unique ability to produce very good Silver Gelatin prints and also other processes such as Platinum / Palladium prints because of the UV blocking characteristics.

Pyrocat HD because of the root Pyro being Pyrocathol produces an Amber colored stain which is more conducive to producing more inherent contrast in the highlights of Silver Gelatin enlarging papers. Pyrogallol based developers produce a green stain and therefore are not as desirable when using Silver Gelatin enlarging papers.

Lastly, Pyrocathcol produces a much tighter grain structure than Pyrogallol. Pyrocat developers are Pyrocathcol based while Pyrogallol is used in PMK, ABC and Rollo Pyro,developers as an FYI

Cheers !

[Kirk Gittings]

I was hoping you or sandy would chime in :) I just use the stuff-not sure why it works so well.

[Ken Lee]

You might find it helpful to read some of the many previous discussions of staining developers on this forum.

See https://www.google.com/search?q=staining+developer+site%3A+largeformatphotography.info&ie=utf-8&oe=utf-8#q=staining+developers+site:largeformatphotography.info

(Although the forum's built-in search engine is limited, Google does a good job and allows you to limit your search to a specific domain by simply adding site: followed by the domain name.)

[Taija71A]

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In your search Barry... You will 'no doubt' come across the following Excellent URL's:
(*Amongst many others...)


http://www.largeformatphotography.info/forum/showthread.php?16066-VC-Papers-Staining-Developers
http://unblinkingeye.com/Articles/PCat/pcat.html
http://www.viewcamera.com/pdf/2006/pyro.pdf

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Best regards,

-Tim.
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[Sirius Glass]

A staining developer adds stain (density) proportionally to the exposed negative. The more highly sensitized areas of the image gain and accept more stain.

The stain has two major positives, first, the film will require less time in solution which directly impacts the sharpness or accutance of the negative and resulting print, the grain is masked to a degree which effectively produces sharper appearing prints.

Second, the stain will increase the effective contrast index of a given negative when the light source is Ultra Violet, used primarily in alternative processes which normally requires a more contrasty negative. Pyro based negatives have the unique ability to produce very good Silver Gelatin prints and also other processes such as Platinum / Palladium prints because of the UV blocking characteristics.

Pyrocat HD because of the root Pyro being Pyrocathol produces an Amber colored stain which is more conducive to producing more inherent contrast in the highlights of Silver Gelatin enlarging papers. Pyrogallol based developers produce a green stain and therefore are not as desirable when using Silver Gelatin enlarging papers.

Lastly, Pyrocathcol produces a much tighter grain structure than Pyrogallol. Pyrocat developers are Pyrocathcol based while Pyrogallol is used in PMK, ABC and Rollo Pyro,developers as an FYI

Cheers !

Nicely related.

[Will S]

Another effect (of pyrocat-hd anyway) is how it affects the same negative for enlarging on silver-gelatin and contact printing on graded silver-chloride like Lodima because of the stain as Steve Sherman outlines above, allowing you to use the same negative for both processes.

[stradibarrius]

Steve, Thanks for this answer. It answers my question completely. For those of us who are not knowledgeable about chemicals and chemical reactions this answer hits the bullseye. Also thanks for the info on Pyrocat vs. PMK, Rollo Pyro.
Would the effect be the same when using a scanner.

A staining developer adds stain (density) proportionally to the exposed negative. The more highly sensitized areas of the image gain and accept more stain.

The stain has two major positives, first, the film will require less time in solution which directly impacts the sharpness or accutance of the negative and resulting print, the grain is masked to a degree which effectively produces sharper appearing prints.

Second, the stain will increase the effective contrast index of a given negative when the light source is Ultra Violet, used primarily in alternative processes which normally requires a more contrasty negative. Pyro based negatives have the unique ability to produce very good Silver Gelatin prints and also other processes such as Platinum / Palladium prints because of the UV blocking characteristics.

Pyrocat HD because of the root Pyro being Pyrocathol produces an Amber colored stain which is more conducive to producing more inherent contrast in the highlights of Silver Gelatin enlarging papers. Pyrogallol based developers produce a green stain and therefore are not as desirable when using Silver Gelatin enlarging papers.

Lastly, Pyrocathcol produces a much tighter grain structure than Pyrogallol. Pyrocat developers are Pyrocathcol based while Pyrogallol is used in PMK, ABC and Rollo Pyro,developers as an FYI

Cheers !

[IanG]

Pyrocat negatives are remarkably easy to print., they also scan very well.

Just a correction it's Pyrocatechin, also known as:

Catechol
pyrocatechol
1,2-benzenediol
2-hydroxyphenol
1,2-dihydroxybenzene

Ian

[Vaughn]

...Would the effect be the same when using a scanner.

Never scanned a pyro negative, but the effect would be different (when scanning there is no emulsion to react to different wavelengths of light). I suppose one could play with the yellow channel to make the effect more similar.

[Peter De Smidt]

When you scan a stained negative in color, you will have three different channel of varying density ranges. With Pyrocat negatives, the blue will have the greatest range, the green a mid range, and red the lowest range. You can pick or blend to your heart's content.

[jp]

With scanning, it mostly shifts the blue in the histogram slightly. Easy to adjust for.

[Patrick13]

When you scan a stained negative in color, you will have three different channel of varying density ranges. With Pyrocat negatives, the blue will have the greatest range, the green a mid range, and red the lowest range. You can pick or blend to your heart's content.

This is neat to know! I will have to try this next time I can experiment for a while. Thanks :)

[Taija71A]

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All uses of the term 'Pyrocathol' in this thread...
Are of course referring to Pyrocatechol (Pyrocatechin).
--
Best regards,

-Tim.
__________