The Increasing Popularity Of Pyro.

[Kirk Keyes]

There is a problem here, which might only be that it is 1:30 AM, but from what you are saying, it seems that if you bleached the silver out of a pyro negative and printed it, the printed image would also ba a negative.

I never claimed that, or that could, would, or should happen.

I think it must be because it is 1:30 AM...

 

[Kirk Keyes]

Because of the claims that have been made, I presume someone has already done this test or something similar.

It sounds interesting. Just keep in mind that the stain varies throughout the neg, so you'll have to correct for that.

 

[ic-racer]

I'm not sure if I follow you on that. Realize I'm talking about a uniformly exposed or fogged test negatives. [For example one 4x5 sheet kept in the dark and another one set out on the counter with the lights on for a few seconds] If these pyro-developed negatives do not have a uniform stain, then pyro its going to be totally inappropriate for my purposes. I would hope the stain is proportion a to the silver density throughout the entire area of the negative. If you are telling me there is going to be more stain in the center or the edges I'm going to say 'not for me' before I even get started.

In practical terms I'll have a local pyro user process my test negatives (John?) and put the negatives in the light path of an enlarger to contact print a 21 step wedge on Ilford MG, in a manner identical to testing a standard MG filter. My personal goal is to see at least a change in density range of one step between a 'plain film base' negative and a 'film base + 2.0 silver density' negative (an ISO(R) change of 15 units). If its less than that, then I suspect I won't be able to appreciate pyro in my darkroom. If the change is more than that then I'd like to start using it on a regular basis.

To satisfy my curiosity I'm also going to quantify the color of the stain with a color transmission densitometer, but really, who cares what color it is. The important thing is how the stain affects the contrast of MG paper.

 

[mikebarger]

When I tested HP5 (4x5), Fred Pickers method, the negatives were uniform in their stain.

I used 510 Pyro, I suspect all of the Pyro's work about the same in this regard.

Mike

 

[Kirk Keyes]

I'm not sure if I follow you on that. Realize I'm talking about a uniformly exposed or fogged test negatives. [For example one 4x5 sheet kept in the dark and another one set out on the counter with the lights on for a few seconds] If these pyro-developed negatives do not have a uniform stain, then pyro its going to be totally inappropriate for my purposes. I would hope the stain is proportion a to the silver density throughout the entire area of the negative. If you are telling me there is going to be more stain in the center or the edges I'm going to say 'not for me' before I even get started.

I think I realized that. The stain will be as uniform as you can develop a sheet of film. I was just trying to point out that areas of low silver density areas will have less stain than areas of high silver density. The stain is fairly proportional to the silver density.

So if you expose the sheet evenly and process it evenly, you should have an even amount of stain on the sheet.

 

[Photo Engineer]

All pyro negatives should have a weak negative dye image and an overall uniform dye due to the inherent fog of the emulsion-developer combination. This is assuming they are properly processed.

The negatives should also have a weak relief image due to the tanning effects of the developing agent(s).

PE

 

[Kirk Keyes]

My personal goal is to see at least a change in density range of one step between a 'plain film base' negative and a 'film base + 2.0 silver density' negative (an ISO(R) change of 15 units).

If I understand you here, you might want to try a "film base + 1.10 silver density" or so neg as well.

A neg with a density range of 2.0 is a pretty dense neg (that is an ISO(R) of 200). That's softer than a Grade 00 paper. I would think you would want something that was suited to about a Grade 2 paper - something with a density range of 1.05 or 1.15 OD (an ISO(R) of 105 to 115).

 

[Tom Kershaw]

PE,

The films I've developed in Pyrocat-HD, TMY-2, Delta 100 & 400, and HP5 Plus have all had a relief image; sometimes more noticeable than at others.

Tom.

 

[Kirk Keyes]

Realize I'm talking about a uniformly exposed or fogged test negatives.

I took a Stouffer 21 step 4x5 tablet and contacted onto my test films. I measured the RGBV density of all the steps with a densitometer, bleached the negs to remove the silver, and then cut individual steps out of the bleached negs and scanned them on the spectrophotometer and measured them on the densitometer.

 

[Photo Engineer]

I took a Stouffer 21 step 4x5 tablet and contacted onto my test films. I measured the RGBV density of all the steps with a densitometer, bleached the negs to remove the silver, and then cut individual steps out of the bleached negs and scanned them on the spectrophotometer and measured them on the densitometer.

And lets see the results!

Remember though that bleaching leaves a faint residual stain just by itself due to unbleachable silver sulfides and iodides.

PE

 

[Photo Engineer]

PE,

The films I've developed in Pyrocat-HD, TMY-2, Delta 100 & 400, and HP5 Plus have all had a relief image; sometimes more noticeable than at others.

Tom.

This comes from the hardening effects of the developers and the formation of dye which swells the emulsion just as in Kodachrome but not to that extent.

Remember that these developing agents were used for Dye Transfer to form the relief image in Matrix and Pan Matrix film.

PE

 

[Kirk Keyes]

And lets see the results!

Remember though that bleaching leaves a faint residual stain just by itself due to unbleachable silver sulfides and iodides.

Didn't I post all this stuff back during the Second Year of the Infamous Pyro Wars?

I scanned B+F areas of film as well so that should show any included affects of the sulfides and iodides, I would think.

 

[sanking]

Didn't I post all this stuff back during the Second Year of the Infamous Pyro Wars?

I scanned B+F areas of film as well so that should show any included affects of the sulfides and iodides, I would think.

Kirk,

I think you posted that stuff on the LF forum. I don't believe Ron visits that site, at least I don't ever recall seeing him post there.

As best I can recall that was in late 2006 or early 2007. The last round of the great wars took place in early 2007.


Sandy

 

[Photo Engineer]

I have about 10 posts on the LFF. Sorry, never saw the data.

PE

 

[mikebarger]

Great Pyro war, sounds Russian, are there monuments and national parks?

No offense met to anyone (or nation), just sounded odd when I first read it.

I had a draft number in my younger years, but not for this conflict

Mike

 

[Sirius Glass]

I must have joined APUG as they were winding down.

Missed the whole thing by that much!

Steve

 

[sanking]

Great Pyro war, sounds Russian, are there monuments and national parks?

No offense met to anyone (or nation), just sounded odd when I first read it.

I had a draft number in my younger years, but not for this conflict

Mike

No monuments or national parks, and no medals for heroism. Even before the last major battle was even over I split for Mexico, and missed that battle and the final desperate suicide assaults. Others slunk off into the hills nursing their wounds. One who was already in Mexico snuck back into the US for a brief visit, then disappeared again. Like Lefty, where he got the bread to travel we will never know. One suffered some kind of personal tragedy and announced he could no longer practice photography.

Those were traumatic times, best left forgotten.

Sandy

 

[Kirk Keyes]

Great Pyro war

I said "Infamous"! ;^)

Anyway, I learned a lot out of my years of service.

 

[ic-racer]

So after wading through some old posts on the LF forums, I don't think the test I outlined will add any new info. Remaining "pyro-neutral" for now.

Here is a link to one of the threads: http://www.largeformatphotography.info/forum/showthread.php?t=22188

 

[Kirk Keyes]

Well, there's several other threads that are much more informative than that one.

 

[eclarke]

I agree with you about this and this has been one of my major complaints about the way some people have promoted pyro developers. But the compensation you can get with VC papers in the highlights can be pretty magical. I have been in some pretty heated exchanges with so-called experts who simply totally failed to understand the fundamental difference in using pyro negatives with graded (blue sensitive) and VC (blue and green sensitive) papers.

Definitely have not seen any kind of veiling in prints that could be attributed to pyro. But I have seen plenty of bad prints that were bad for a variety of reasons.

Sandy King

I always make at least 2 sheet of a photograph, regardless of format, which allows me to take different approaches to the negatives and also provides a nice backup. Film is still cheaper than all the other aspects of making photographs so I try to be a little more discerning in my choice of subjects and make the extra sheets. I can try my conventional developer, pyro or a different development routine to fine tune the photograph...Evan Clarke

 

[mikebarger]

I think that is the approach I'm going to follow. So far I've only made one negative with the 4x5. Making that second one may be a good idea as I learn this format. Sure wish work didn't take up so much time.

Mike