Using Graded paper vs VC paper

[Cor]

Throwing in another test:

Properly expose (matter of debate) a negative and develop in a pyro developper (also matter of debate, but say: Pyrocat-HD). Make good prints on VC and fixed paper.

Bleach the stain (there is a bleach based on potassium permangate, have to dig that one up though) which only removes the stain, not the silver image.

Repeat the printing on VC and fixed paper.

Compare results and draw conclusions.

Anybody with spare time.....?

(if you want to extend one could shoot different scenes (high and low contrast) and different development times to address the point raised by John Bond, even bleach the silver image and print the stain image)

Best,

Cor

 

[Ian Grant]

You're making it too complex, a permanganate bleach would be acidified Potassium Permanganate and Potassium bromide but there's no point.

The point that Jed's made which is correct is that the stain with a Pro dev is proportional. I'm 100% certain that the stain has a slight effect on localised contrasts.

The simple test is two negatives one processed in a standard developer like D76 the other in a staining developer like Pyrocat HD or PMK, both developed to give a normal contrast image printed on say Gd 2 fixed grade paper. Then comparable prints made to match on a VC/MG paper. There should then be a difference, the stained negative needing a higher contrast setting than the unstained.

Ian

 

[Jed Freudenthal]

Throwing in another test:

Properly expose (matter of debate) a negative and develop in a pyro developper (also matter of debate, but say: Pyrocat-HD). Make good prints on VC and fixed paper.

Bleach the stain (there is a bleach based on potassium permangate, have to dig that one up though) which only removes the stain, not the silver image.

Repeat the printing on VC and fixed paper.

Compare results and draw conclusions.

Anybody with spare time.....?

(if you want to extend one could shoot different scenes (high and low contrast) and different development times to address the point raised by John Bond, even bleach the silver image and print the stain image)

Best,

Cor

I mentioned the removal of the stain before.

And maybe that might help:
a quotation of wikipedia:


http://en.wikipedia.org/wiki/Photographic_developer

Other developing agents in use are*p-aminophenol,*glycin*(N-(4-hydroxyphenyl)glycine),*pyrogallol*and*catechol. When used in low sulfite developer composition, the latter two compounds cause gelatin to harden and stain in the vicinity of developing grains. Generally, the optical density of the stain increases in the heavily exposed (and heavily developed) area. This is a property that is highly sought after by some photographers because it increases negative contrast in relation to density, meaning that highlight detail can be captured without "blocking" (reaching high enough density that detail and tonality are severely compromised). Hydroquinone shares this property. However, the staining effect only appears in solutions with very little sulfite, and most hydroquinone developers contain substantial quantities of sulfite.

So one do the test with a high and low sodium sulfite content in a pyrogallol developer, like has been done before.

Jed

 

[Nicholas Lindan]

Suggested protocol:

• Contact step tablets to a number (say 10) of sheets of film - overexpose as the films' response will be somewhere along the step tablet
• Develop the sheets in D-76 and one in a repeatable pyro developer: PMK or PCat. Pull the sheets at -20%, -10%, 0, +10%, +20% of nominal developing time. Changes in overall gamma will effect the 'highlight separation' so it will be important to find a pair of negative with equal gamma from each developer.
• Contact the equal-gamma negatives to the papers and VC filtrations in question
• Measure the HD curve densities, paying particular attention to the highlights
• Calculate and plot the local contrast - density change in the print per step
• Sit back, scratch head and wonder what the results mean

I suggest contacting as we are looking strictly at the effect of pyro stain - the elimination of all other variables is important to getting the best results. Contacting removes any effects due to cameras, enlargers and flare.

Doing experiments with pictorial negatives is a waste of time - evaluation is purely subjective and the discussion soon devolves into something akin to one of those impassioned and nonsensical discussions of audio gear. You have to put numbers to it.

 

[Doremus Scudder]

How about this:

Make a negative of a normal-contrast scene and develop it in a non-staining developer, or better, and for more quantifiable results, use a step wedge.

Evenly expose another negative to, say Zone VII and develop it in a staining developer, preferably one using pyrogallol as its developing agent, since, as Sandy King's articles point out, the pyrogallol stain is a more reactive color for VC papers than pyrocatechol stain.

Bleach the silver from the pyro negative, effectively creating a VC filter the color of the pyro stain and corresponding to the stain in a Zone VII portion of a pyro negative.

Print the first negative or the step wedge on both VC paper and graded papers using white light (using the same light source, of course), with and without the pyro negative filter in place. Adjust print exposure to match a shadow density and take a look at the highlights. Densitometer readings would quantify the effect of a "Zone VII stain" on the higher print values for both types of paper. This may be enough to draw some conclusions from.

If you need more data, make pyro-stain filters for other negative densities (e.g., Zones IV, V, VI and VIII) and do the test with all those and use the data to plot curves.

BTW, Ralph, Nicholas, Ian and others, I believe our claim should be a dual one, something like:

The color of pyro stain acts as a proportional variable-contrast filter for VC papers by blocking blue light and lowering contrast in proportion to the amount of stain. In addition, this same property, i.e., the proportional blocking of blue light, increases contrast on graded papers that are blue-sensitive only, since it reduces the amount of blue light reaching the paper in proportion to the amount of stain.

My suggested test should eliminate all variables except the stain by doing the test with and without stain for both types of paper using the same neg or step wedge.

I'd be interested in your thoughts on the validity of my proposed test.

I'm unfortunately in Vienna for some months and away from my darkroom, but maybe someone is interested in trying the test. It would be interesting to get to the bottom of this. For me, the notion that a pyro stain works as stated in my "claim" above is logical and plausible and well-worth investigating.

Best,

Doremus Scudder
www.DoremusScudder.com

 

[Jed Freudenthal]

The point that Jed's made which is correct is that the stain with a Pro dev is proportional. I'm 100% certain that the stain has a slight effect on localised contrasts.

Ian

In my test with and without stain, I observed an effect on the local contrast ( probably as result of optical conditions). The 'look' of a print ( 4x linear) is rough without the stain, maybe as result of light scattering on silver crystals. The 'look' of a print ( 4x linear) with stain has a pleasant tonality. Moreover, the stain seems to blur the shape of the grain. In enlarged prints, the stain seems to lead to better smoother tonality-changes. The stain might scatter light in a diffuse manner.
Therefore, the stain adds more than just optical density. But these changes are probably not significant on contacts. I observe them in enlarged prints.

Jed

 

[RalphLambrecht]

Suggested protocol:

• Contact step tablets to a number (say 10) of sheets of film - overexpose as the films' response will be somewhere along the step tablet
• Develop the sheets in D-76 and one in a repeatable pyro developer: PMK or PCat. Pull the sheets at -20%, -10%, 0, +10%, +20% of nominal developing time. Changes in overall gamma will effect the 'highlight separation' so it will be important to find a pair of negative with equal gamma from each developer.
• Contact the equal-gamma negatives to the papers and VC filtrations in question
• Measure the HD curve densities, paying particular attention to the highlights
• Calculate and plot the local contrast - density change in the print per step
• Sit back, scratch head and wonder what the results mean

I suggest contacting as we are looking strictly at the effect of pyro stain - the elimination of all other variables is important to getting the best results. Contacting removes any effects due to cameras, enlargers and flare.

Doing experiments with pictorial negatives is a waste of time - evaluation is purely subjective and the discussion soon devolves into something akin to one of those impassioned and nonsensical discussions of audio gear. You have to put numbers to it.

This will work just fine. I have this done for several film in D76. All I need is someone to make the pyro negatives, and we will have development times to create two negatives of identical gamma. That's the first step.

Who can help with the pyro negatives?

 

[pawlowski6132]

Easy to prove using Densitometry.

Vlad

I have doubts. The trouble is one could not compare a before and after negative to prove the point.

 

[RalphLambrecht]

Easy to prove using Densitometry.

Give me the data and I'll do it!

 

[Jed Freudenthal]

Suggested protocol:

• Contact step tablets to a number (say 10) of sheets of film - overexpose as the films' response will be somewhere along the step tablet
• Develop the sheets in D-76 and one in a repeatable pyro developer: PMK or PCat. Pull the sheets at -20%, -10%, 0, +10%, +20% of nominal developing time. Changes in overall gamma will effect the 'highlight separation' so it will be important to find a pair of negative with equal gamma from each developer.
• Contact the equal-gamma negatives to the papers and VC filtrations in question
• Measure the HD curve densities, paying particular attention to the highlights
• Calculate and plot the local contrast - density change in the print per step
• Sit back, scratch head and wonder what the results mean

I suggest contacting as we are looking strictly at the effect of pyro stain - the elimination of all other variables is important to getting the best results. Contacting removes any effects due to cameras, enlargers and flare.

Doing experiments with pictorial negatives is a waste of time - evaluation is purely subjective and the discussion soon devolves into something akin to one of those impassioned and nonsensical discussions of audio gear. You have to put numbers to it.

Some comments to your suggested protocol:
I would like to see a statement what the objective of the study is, and the strategy how to answer this.
From your protocol, I get the idea that you are trying to determine densities. Stain, however will contribute to the optical density not to the density. Therefore you should determine the optical density.
Moreover, you should not contact your negative, but have it enlarged. Your enlarger is part of the optical system ( like with the Callier effect).

I would use a developer with a considerable amount of proportional stain. A pyrogallol developer with low sulfite is the common solution. Neither pyrocat or PMK are good candidates for tis test.

The pyrogallol negative has an advantage in the highlights. With D 76 the high lights will be blocked. How is this going to be handled?

Jed

 

[RalphLambrecht]

Jed

Please explain what you mean with 'optical density'. The density we measure with a densitometer IS optical density by definition.

http://en.wikipedia.org/wiki/Optical_density

Maybe you're using an 'unfortunate' term? Any other way to describe it?

 

[Jed Freudenthal]

Jed

Please explain what you mean with 'optical density'. The density we measure with a densitometer IS optical density by definition.

http://en.wikipedia.org/wiki/Optical_density

Maybe you're using an 'unfortunate' term? Any other way to describe it?

Optical density is the same as (wavelenth dependent) absorbance. When I want to measure the contribution of a yellow stain, I filter in blue. This is the usual way to measure the contribution of a yellow stain. Bob Herbst has published this e.g. for a pyrogallol stain:
http://unblinkingeye.com/Articles/Pyro/pyro.html and has measured the absorbance of the stain and showed that it is proportionalto the stain. Bob calls it the density in blue, but that is really an absorbance in blue. But many people, including myself made such measurements. Within APUG, Tom Hoskinson made such measurements, at least he told me that.
But, the absorbance of the stain is just part of the story. The physical (optical) properties of the stain differ in more ways than just the wavelength from those of the silver crystals. That is the reason, that one should include the complete optical arrangment (the enlarger).
As far as I see it, you are are going to repeat the measurements of Bob. If that is not true, I do not understand your objectives. And Bob is using a pyro developer with moderate staining to avoid to high optical densities. In your experiment you could optimize for maximum stain.

Jed

 

[RalphLambrecht]

... As far as I see it, you are are going to repeat the measurements of Bob. If that is not true, I do not understand your objectives. ...

Ian pointed us to Bob Herbst's article, and I already wrote a comment in post #74. I do not wish to repeat his test, but I like to measure the contrast effect on paper. Unfortunately, without some help from people who actually use staining developers and can provide negative of a step wedge, it won't happen.

 

[Ian Grant]

Ian pointed us to Bob Herbst's article, and I already wrote a comment in post #74. I do not wish to repeat his test, but I like to measure the contrast effect on paper. Unfortunately, without some help from people who actually use staining developers and can provide negative of a step wedge, it won't happen.

I don't have a step wedge, but if you shoot the film I'll process it for you, or send you some developer when I'm back in the UK in a couple of weeks.

Ian

 

[Jed Freudenthal]

Ian pointed us to Bob Herbst's article, and I already wrote a comment in post #74. I do not wish to repeat his test, but I like to measure the contrast effect on paper. Unfortunately, without some help from people who actually use staining developers and can provide negative of a step wedge, it won't happen.

Is that your objective. I can hardly understand this. If yellow is measured; is that not enough? First of all, use the enlarger to make the print.
I made a photo of a landscape with 98 % deep shadows but full detail. 2% of the photo was a house with a white wall in the sun. A lumiminosity range well above 7. The developer in case was catechol.
I made a print on grade 2 paper ( ISO range =100), such that there was some detail in the wall of the house far away ( one can just observe the bricks in the wall). Then the shadows have little detail, and the shadows are not completely black, but not really acceptable.
Now I made a print on VC( MCC 110). I set yellow=0 and give it some magenta. The house is printed like on the graded paper, but the shadows come out with full detail. And when I increase the modulation ( magenta =65 on a Devere) the details in the shadows are getting more and more pronounced. The shadows are coming alive. The more magenta the softer the print looks in the shadows. It sounds contradictory. And with changing the exposure one can fine-tune the appearance of the high lights.
This is a typical example where I prefer VC above graded. And at the same time it demonstrates the difference on a paper print.
VC has an additional advantage over graded in situations with high luminosity ranges with stained negatives. Hans Windisch has already described in the 1930 's the advantage with graded paper. With VC you can go a step further.

Jed

 

[RalphLambrecht]

I don't have a step wedge, but if you shoot the film I'll process it for you, or send you some developer when I'm back in the UK in a couple of weeks.

Ian

Yes, I can shoot the film and send it to you. 4x5 or 120?

 

[RalphLambrecht]

Is that your objective. I can hardly understand this. If yellow is measured; is that not enough? First of all, use the enlarger to make the print. ...

I'm with Nicholas on this one. Only a step wedge will do, everything else leaves too much room for subjective interpretation. Also, if the final print is to benefit, then the final print is what has to be measured. Yes, the enlarger will be used to make the prints.

 

[Ian Grant]

Yes, I can shoot the film and send it to you. 4x5 or 120?

It depends what range of development times you want etc, I use an old Jobo tank for 5x4 so individual sheets is not easy but not impossible - just a risk of scratching or finger marks, and with 120 rolls can be cut and placed in more than one spiral. So it's really down to what you need.

I've not booked our flights yet but we will be in the UK sometime just after the 25th so there's no immediate rush.

Ian

 

[RalphLambrecht]

Ian

I would be interested in an average gradient of roughly 0.57. If you get close to that, I can adjust my D76 process to match it reasonably close.

What do you think about Jed's concern about what staining developer to use?

'I would use a developer with a considerable amount of proportional stain. A pyrogallol developer with low sulfite is the common solution. Neither pyrocat or PMK are good candidates for tis test.'

 

[2F/2F]

Some of the graded papers around right now are very beautiful. That alone is reason enough for me to use them. However, since they are available in such a limited range of grades (Oriental and Ilford have only 2 and 3, for example.) I generally only use them when I am shooting using precise tonal placement using sheet film or separate 120 backs. For the average roll of film that I shoot, I use VC paper, as there is usually so much variety within the roll, and I cannot tailor each shot to the paper with roll film.

If you want to experiment with graded papers, I'd suggest the Fotokemika Emaks as a great starting point. It has a beautiful look, and is available in three grades: 2, 3, and 4.

I'd also suggest a little darkroom trick I have picked up. Keep one bottle of 10 percent carbonate and one bottle of 10 percent bromide on hand when printing. Add some carbonate to your paper developer to raise contrast a bit, and bromide to lower it a bit.

But this "spiking" of your stock developer will only get you so far. When working with graded papers, it is almost a necessity to really explore different paper developers and how they can be used to manipulate the graded paper.

And I am sure someone has said this by now, but you do not use filters with graded papers.

 

[Ian Grant]

Bromide increases contrast with most emulsions, that's why it's used in very high quantities in Graphic arts developers like ID-13.

However with Chloro-bromide emulsions it increases warm tones and suppresses development/paper speed, but develop long enough and the contrast would be higher and the speed restored.

Ian

 

[Nicholas Lindan]

an average gradient of roughly 0.57

Last week I cleaned the place up and in the general tossing of things threw out about 100 step-wedge pyro negatives that were used in the development and testing of the Pyro enlarging meter. Never wanted to see the damn things ever again. Oh, well, c'est la vie.

A few notes:

It would be interesting to know how it is planned to determine the CI of a pyro negative.

A point to keep in mind is that the stain to silver ratio isn't necessarily linear. Some combinations of film and developer are, some aren't. This throws a big monkey wrench into attempts at using a densitometer. It is possible to correlate densitometer readings to print densities - but the densitometer readings themselves have little meaning when it comes to measuring the niceties of the image.

Low sulfite pyro formulations go bad minute-by-minute from oxidation with contact with the air. Sensitometric results are not repeatable. Additionally these formulations produce copious and variable amounts of over-all stain; the overall stain is often mistaken for image stain as it masks a true appreciation of the real amount of image stain.

 

[Ian Grant]

Ian

I would be interested in an average gradient of roughly 0.57. If you get close to that, I can adjust my D76 process to match it reasonably close.

What do you think about Jed's concern about what staining developer to use?

'I would use a developer with a considerable amount of proportional stain. A pyrogallol developer with low sulfite is the common solution. Neither pyrocat or PMK are good candidates for tis test.'

Well he has a point about starting with the extremes. Maybe one of the older Pyro's like Ilford ID-1 would be better, I don't use them but could easily mix one up.

On the other hand we are really more interested in the developers in common use now, and the two main staining developers are Pyrocat HD & PMK.

Needs some thought, what's the Step wedge ? Would it be easier for me to shoot and process.

Ian

 

[cowanw]

If you can snag a set of filters of the old Bakelite screw on lens holder design, either Kodak or Dupont, I think you will get a much better grade 5

I bemoan the loss of Grade 5 paper --I cannot seem to get Grade 5 with Magenta filters in my LPL or Durst with the built-in filters and have tried some 'below lens' filters and they seem to have faded .

 

[Jed Freudenthal]

Ian


What do you think about Jed's concern about what staining developer to use?

'I would use a developer with a considerable amount of proportional stain. A pyrogallol developer with low sulfite is the common solution. Neither pyrocat or PMK are good candidates for tis test.'

This is not really a concern. You want to test a response on the stain. So my advice is to optimise the stain for the test. It is a pure technical advice.
My main interest in staining developers is from an artistic point of view and their ability to cover a large luminosity range. There are thousands of staining formulas around, each with their own qualities.
Formulas like D-76 were introduced around 1926, when the 35 mm film came on the market. The reason was that the grain of pyrogallol developers was unacceptable. But in the mean time the film emulsions have been modified in such a way, that pyrogallol negatives can have much smaller grain. An 8-10 x magnification is possible without problems. This fact is possibly one of the factors that the staining formulas got more attention in the last 20 years.

I would suggest to Ralph, just try the staining developers and see how they behave. There are properties you cannot see in density measurements. The artistic note.

Jed