Edge efects with Pyrocat-HD

Dave Krueger · Jan 2, 2007

FX-1, FX-2, TFX-2, Beutlers, etc

Do all acutance developers require minimal agitation techniques for edge effects? FX-1, FX-2, TFX-2, Beutlers, etc are supposedly acutance devlopers. From what I've read, FX-1 may have edge effects too stark to be appealing and I assume that is with traditional agitation techniques.

Dave Krueger · Jan 2, 2007

Tom Hoskinson said:
Dave,here is my procedure For Semi-Stand development in a plastic tank:

Developer dilution = 1:1:100 (with 70F distilled or deionized water)

1.Distilled or Deionized 70F water presoak for 5 minutes (with ocasional agitation by gentle torus inversion), then dump presoak water.

2. Fill tank with 70F developer and agitate initially for 30 seconds by gentle torus inversion at 70 F.

2. Then stand for 9 minutes with no agitation AND:

3. Agitate for 30 seconds by gentle torus inversion

4. Stand for 9 minutes with no agitation, then dump developer.

5. Rinse with 70F water and dump

6. Fix in non-hardening rapid fix at 70F (with continuous agitation)

7. Wash in 70F water and dry

Didn't mean to ignore this. Just got sidetracked.

In order to increase edge effects, wouldn't I need to increase the time in the developer and less agitation? I used a developing time of an hour, while you're suggesting 18 minutes. Seems like that is going the wrong direction, although I admit that my dilutions are different...

What is torus inversion agitation? Is that inverting the tank and rotating it at the same time? That's what I presently do, but I worry that the chemicals sloshing end to end in that big ol' jobo drum will knock the sheets right out of the reel. I was thinking of switching to my combi-plan in the future. The combi also requires less chemical.

-Dave

Tom Hoskinson · Jan 2, 2007

Dave Krueger said:
Didn't mean to ignore this. Just got sidetracked.

In order to increase edge effects, wouldn't I need to increase the time in the developer and less agitation? I used a developing time of an hour, while you're suggesting 18 minutes. Seems like that is going the wrong direction, although I admit that my dilutions are different...

What is torus inversion agitation? Is that inverting the tank and rotating it at the same time? That's what I presently do, but I worry that the chemicals sloshing end to end in that big ol' jobo drum will knock the sheets right out of the reel. I was thinking of switching to my combi-plan in the future. The combi also requires less chemical.

-Dave

Dave, the semi-stand developing procedure I gave you works fine with single sheets of PL100 sheet film in a a BTZS type plastic tank. It also works fine in a Jobo tank with 35mm and/or 120 rollfilm. I fill the tank with developer. Pyrocat is a very low cost developer - especially so if you mix yours from scratch like I do.

I personally use 18 minutes total at 70C with the 1+1+100 dilution of Pyrocat with Efke/Adox PL100 because that combination works for me (I contact print). If I needed a higher or lower Contrast Index, I would change the dilution ratio and/or development time.

Torus inversion agitation is accomplished by gently inverting the tank while rotating it with a slow,gentle twisting motion.

Photo Engineer · Jan 2, 2007

Stand and semi stand development work by increasing the local concentration of acid, iodide, and bromide in dense image areas, and reducing the concentration of base and developing agent. That is what leads to the effect in the left hand graph I posted above.

However, since bromide and iodide drift in the solution, and are 'heavy' with respect to the solution density, they tend to drift downwards creating a smear in the edge effects commonly called "bromide drag".

You therefore have to be particularly careful of bromide drag if you under agitate during development. You can also get this effect through over agitation due to the 'pumping' action of the agitation creating flow patterns.

Agitation can be a two edged sword.

PE

sanking · Jan 2, 2007

Photo Engineer said:
Agitation can be a two edged sword.

PE

Very well said. This is something I always try to tell people about stand and semi-stand development.

The same is also true about staining developers with VC papers, IMO. Compensation in the highlights is a great advantage, but sometimes this comes at the cost of reduced separation (less contrast) in the mid and upper-mid tones.

So many important things to understand. So little time to learn them all.

Sandy King

sanking · Jan 2, 2007

Photo Engineer said:
However, since bromide and iodide drift in the solution, and are 'heavy' with respect to the solution density, they tend to drift downwards creating a smear in the edge effects commonly called "bromide drag".

You therefore have to be particularly careful of bromide drag if you under agitate during development. You can also get this effect through over agitation due to the 'pumping' action of the agitation creating flow patterns.

Agitation can be a two edged sword.

PE

PE,

Clearly some developer formulas work much better than others with reduced agitation. Is there any one (or two) things that might explain why?

I am particulary curious to know if the specific gravity of the solution might play a role in reducing or enhancing the results of bromide drag.

Sandy

Photo Engineer · Jan 2, 2007

Sandy, I agree, too little time.

Another big problem I warn of is using VC papers to print color negatives. This causes variable contrast as a function of color which is really odd.

PE

Photo Engineer · Jan 2, 2007

Well, SG of the developer is generally lower in areas of no development than in areas of development, and you can see a bloom of chemicals diffusing away from the film that varies as a function of the image density. This is due to bromide and iodide being released. In these areas, the SG is somewhat higher. Other components in the developer maintain a relative steady state in density (SG). (That is rather simplistic though but near enough)

So, the best developers for low agitation would be those well buffered in bromide and iodide. I think that might help more than anything else. But, I really don't know for sure, as Kodak always recommended good agitation, and our tests were run under 'normal' agitation which was standard for all release processes. Stand development was a no-no.

The old Kodak drum processor for color paper was notorious for giving bromide drag due to high agitation, the other end of the spectrum (two edged sword, remember?) and so a special CP5 developer was used there to mitigate the effects of agitation. It had higher bromide, an extra shot of an electron transport agent, and an antifoggant. It then required an after wash for about 30" or so to even out development effects.

I can remember hours of lab testing of paper and developer formulations for bromide drag in color products which are espeically prone to this effect with over or under agitation.

PE

Dave Krueger · Jan 3, 2007

Well, the results I got with minimal agitation with pyrocat seemed exceptionally even, in my narrow range of experience. I wouldn't hessitate to use the same reduced agitation again. The compression of the highlights does not seem so excessive as to be a reason to rule out Pyrocat HD for VC papers, although I didn't like Pyrocat MC for that specific reason.

But, to repeat my question, Do all acutance developers require minimal agitation techniques for edge effects? FX-1, FX-2, TFX-2, Beutlers, etc are supposedly acutance devlopers. Do they not provide the kind of edge effects we're discussing using simple traditional agitation techniques (every 30 or 60 seconds)?

noseoil · Jan 3, 2007

Dave, my understanding of the "edge effects" question is that they are a byproduct of reduced agitation. Not having used the above "acutance" developers (F series), I don't know how they work with respect to edges.

If you take a look at PE's answer about specific gravity and image density, he seems to be saying that the edge separation is partly due to the change in the film and partly due to the effects of reduced agitation and the migration of chemistry.

How did your minimal agitation negatives look at the edges of light and dark? Were they crisp and with plenty of shadow detail? tim

gainer · Jan 3, 2007

Some years ago I did some experiments with stand development using the "normal" strength of the developers and got lots of unevenness, some in the form of obvious streaks and some more subtle. Lately I have been using much greater dilution and much longer times, and if I'm getting uneven development, it is not enough to be seen in 35 mm. The scale effects may be such that the variation across the frame might be more apparent in 4x5 or larger.

The edge effects we seem to covet are difficult to avoid completely from what I have read and seen. There is a problem due to the fact that the eye provides edge effects when the image has sharply defined edges. These will vary with viewing distance and illumination. If you see obvious signs of edge effects in a print, look at them through a loupe and if they are in your eye, they will disappear or be greatly diminished.

Dave, a very small amount of blue or magenta filtration might change the highlights on VC paper.

Dave Krueger · Jan 3, 2007

noseoil said:
How did your minimal agitation negatives look at the edges of light and dark? Were they crisp and with plenty of shadow detail? tim

I didn't notice a pronounced effect, but I was only looking at an 8x10 print from a 4x5 negative. Greater enlargement may make the effect more obvious. The print from the reduced agitation negative did show an increase in contrast in the grass which consists of a lot of very fine detail. Before starting this thread, I was looking at the edges of broader areas and wasn't able to detect a difference. Some of the posts here made me think that I should re-examine the print and look in areas of finer detail.

-Dave

Dave Krueger · Jan 3, 2007

gainer said:
Dave, a very small amount of blue or magenta filtration might change the highlights on VC paper.

Most of my testing with pyrocat HD and MC have used Xtol negatives as a basis of comparison, always using identically exposed negatives. I found that HD compared very well to Xtol in terms of contrast even up into the highlights. The MC showed a significant compression of highlights which, after discussion on the forums, I attributed to the more yellowish stain color of the MC negative. I could have increased the magenta filtration to compensate, but that would have increased the overall contrast as well. That was sufficient to throw the MC out of the race, since I didn't see any other benefits of using MC that would compensate for the highlight compression.

Alan Johnson · Jan 3, 2007

"Do all acutance developers require minimal agitation techniques for edge effects?"
No,but you probably get more,IMO.
With development in a rotary machine there is some edge effect with D76 1+1 and with Beutlers,see Controls in Black and White Photography by R.Henry,p214,p240.
I tested Rodinal with with various agitation time intervals using Tri-X:
www.apug.org/forums/b-w-film-paper-chemistry/24818-visible-rodinal-stand-development-effects.html
In this case the amount of edge effect increased with time interval.

sanking · Jan 3, 2007

Dave Krueger said:
Most of my testing with pyrocat HD and MC have used Xtol negatives as a basis of comparison, always using identically exposed negatives. I found that HD compared very well to Xtol in terms of contrast even up into the highlights. The MC showed a significant compression of highlights which, after discussion on the forums, I attributed to the more yellowish stain color of the MC negative. I could have increased the magenta filtration to compensate, but that would have increased the overall contrast as well. That was sufficient to throw the MC out of the race, since I didn't see any other benefits of using MC that would compensate for the highlight compression.

How are you printing the VC papers? If you introduce enough magenta into the filtration highlight compression is entirely eliminated with all staining developers, regardless of the exact color, because the magenta filtrtation blocks light to the green sensitive low-contrast green layer. If you are using a VC or MC filter set, the number # at which all light to the green layer is blocked is about #3.5. If you use a #3.5 or higher VC filter and still get highlight compression, something else other than the stain is the cause.

Sandy King

Photo Engineer · Jan 3, 2007

I agree 100% with what Sandy says. This is a very important question here.

PE

Dave Krueger · Jan 3, 2007

sanking said:
How are you printing the VC papers? If you introduce enough magenta into the filtration highlight compression is entirely eliminated with all staining developers, regardless of the exact color, because the magenta filtrtation blocks light to the green sensitive low-contrast green layer. If you are using a VC or MC filter set, the number # at which all light to the green layer is blocked is about #3.5. If you use a #3.5 or higher VC filter and still get highlight compression, something else other than the stain is the cause.

Sandy King

I'd have to go back and look at my notes for those HD/MC prints. I don't use a VC filter set. I just dial in magenta on a color head. I'm at work, so the notes aren't handy at the moment.

But, I don't quite understand how adding magenta or blue is going to reduce just the highlight compression without increasing the contrast over the rest of the tonal scale.

Also, if a grade 3.5 filter prevents any exposure of the green layer, how can there be any increase in contrast when using higher numbered filters?

I'm like the little annoying kid who keeps asking why, why, why... haha!

sanking · Jan 3, 2007

Dave Krueger said:
I'd have to go back and look at my notes for those HD/MC prints. I don't use a VC filter set. I just dial in magenta on a color head. I'm at work, so the notes aren't handy at the moment.

But, I don't quite understand how adding magenta or blue is going to reduce just the highlight compression without increasing the contrast over the rest of the tonal scale.

Also, if a grade 3.5 filter prevents any exposure of the green layer, how can there be any increase in contrast when using higher numbered filters?

I'm like the little annoying kid who keeps asking why, why, why... haha!

It does not matter whether you use VC filters or dial in the magenta. At some point the magenta blocks green light, and when that happens the low contrast green senistive part of the emulsion is not exposed. This gives you a print made up mostly, or entirely, of the high contrast blue sensitive part of the emulsion. The result is increased contrast and no highlight compression.

This is a very important concept that has not been adequately addressed in the literature on staining developer.

Sandy King

Dave Krueger · Jan 3, 2007

sanking said:
It does not matter whether you use VC filters or dial in the magenta. At some point the magenta blocks green light, and when that happens the low contrast green senistive part of the emulsion is not exposed. This gives you a print made up mostly, or entirely, of the high contrast blue sensitive part of the emulsion. The result is increased contrast and no highlight compression.

That still doesn't answer my two questions.

1. How is adding magenta or blue is going to reduce just the highlight compression without increasing the contrast over the rest of the tonal scale? Sure, I might eliminate the highlight compression, but at a cost of having objectionably high contrast in the other tones.

2. If, as you say, a grade 3.5 filter prevents any exposure of the green layer, how can there be any increase in contrast when using higher numbered filters?

gainer · Jan 3, 2007

Can you see the clouds in the negative? When I have this problem it is usually because the combination of cloudy sky and sunlit ground is a dual scene. The total brightness range is too wide to make an interesting print without dodging or burning. I can see in the negative there are clouds to be had, but when I print with a paper grade (or VC filter) that prints the full range of the ground scene, that sky scene is washed out. There isn't any developer or developing procedure that will reallly cure this situation. I might better have used a yellow, red or green filter over the camera lans, but I seldom do. Let's assume I have a developing scheme that will produce a straight line on a density-log exposure plot all the way from the bottom to the max density of the film. It will not fit on paper unless I reduce the contrast index so far that nothing looks good. I want black to white in the ground scene, and dark sky with brilliant clouds. If I can see the clouds in the negative, I know I can print them, but not at the same printing exposure I use for the ground.

Maybe I'm not much help, but I know that if I can print the sky and the ground on paper but with different printing exposures, I can make a good print of the whole scene, but it will take some manipulation, and there's no way I can avoid it.

Dave Krueger · Jan 3, 2007

gainer said:
Maybe I'm not much help, but I know that if I can print the sky and the ground on paper but with different printing exposures, I can make a good print of the whole scene, but it will take some manipulation, and there's no way I can avoid it.

Ok, I found my previous thread. The picture is here:

http://www.kruegerphoto.com/pyrotest.jpg

Both the HD and MC negatives printed quite well without manipulation, but I noticed there was some contrast issues with the MC. I posted about it here:

(there was a url link here which no longer exists)

See the second last post by Sandy. I'm pretty sure he hit the nail on the head because there really appeared to be reduced contrast in the highlights.

sanking · Jan 3, 2007

Dave Krueger said:
That still doesn't answer my two questions.

1. How is adding magenta or blue is going to reduce just the highlight compression without increasing the contrast over the rest of the tonal scale? Sure, I might eliminate the highlight compression, but at a cost of having objectionably high contrast in the other tones.

2. If, as you say, a grade 3.5 filter prevents any exposure of the green layer, how can there be any increase in contrast when using higher numbered filters?

1. Because as you add magenta you progressively reduce the impact of the stain, since the green part of the emulsion is less and less in play. This reduces or eliminate shouldering, but the rest of the curve is not affected.

2. It is not that all green light is blocked by a #3.5 filter, but that as you increase the amount of magenta more and more, more green light is blocked. At 3.5 a very great percentage of the green light is blocked, but you have to go all the way to the highest number to block close to 100%. However, at 3.5 the blocking is already so great that the yellow/greeen/brown stain of the negative is no longer in play, I as mention above.

I have run curves on this and when you get to filter #3.5 with VC papers the curve is virtually identical to what you would see with a graded paper that has only sensitivity to blue light. That is, there is no shoulder compression that can be contributed to stain.

Sandy King

Photo Engineer · Jan 3, 2007

Sandy, some of this is covered in the article by Dickerson and Zawadski that I mentioned elsewhere.

All VC papers respond differently to VC filtration.

PE

sanking · Jan 3, 2007

Photo Engineer said:
Sandy, some of this is covered in the article by Dickerson and Zawadski that I mentioned elsewhere.

All VC papers respond differently to VC filtration.

PE

Do they treat staining developers in that article? I was under the impression that staining developers had been largely enlarged for decades in the scientific literature?

Sandy

Photo Engineer · Jan 3, 2007

No, D&S only cover the papers themselves and their atypical response in contrast to filtration.

PE

Edge efects with Pyrocat-HD

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