Using Graded paper vs VC paper

[RalphLambrecht]

Jed

I'm sorry, but I need to see the data to believe it. There are too many myths in photography due to the lack of hard evidence, and too many claims are hiding behind 'the results is all that counts for most people'.

With a little effort, one could come up with test and prove or disprove the claim. Until then, I'm with Ian, and must say that I have not noticed a visible contrast increase in highlights either.

 

[Ian Grant]

Sorry, but I really don't see a difference between the two statements.

One is setting exposure etc for the highlights then adjusting paper contrast grade to conrol the shadows, emphasis is on the highlights first.

The second is placing the emphasis on shadow detail and it's micro contrasts, then bringing the highlights under control.

The difference is in approach and while it may not be important in some images it may well affect choice of paper, development techniques and other controls etc in others.

Ian

 

[Jed Freudenthal]

Jed

I'm sorry, but I need to see the data to believe it. There are too many myths in photography due to the lack of hard evidence, and too many claims are hiding behind 'the results is all that counts for most people'.

With a little effort, one could come up with test and prove or disprove the claim. Until then, I'm with Ian, and must say that I have not noticed a visible contrast increase in highlights either.

A couple of weeks ago we had an APUG darkroom-workshop in the Netherlands with the theme 'contrast control with variable contrast papers' . The focus was: how to handle the micro and macro contrast with the three filters: magenta, yellow, and the proportional stain filter ( if present) and the exposure.
Here we had prints on graded paper as well as prints on variable contrast from the same stained negative. It are two worlds. I expose and develop my negatives, so that I can print on graded ( one grade) as well as on VC paper. I use the papers in a complementary way. But you have to see it, to really understand what I mean. If you are in the area.

Jed

 

[Ian Grant]

Jed, I can partly understand and agree with what you're saying but few Graded papers have direct MG/VC equivalents.

So if I took a stained and unstained negative and printed them both straight, no dodging, burning, developer controls etc on Graded and <G/VC papers of/at the same grade then yes I might well see some differences due to the stain. However if I then went on to make exhibition prints I could get very close with all combinations.

I guess I'd liken the effects of a staining developer with MG/VC papers to mild print flashing, helping to reduce the contrast in the highlights, but it's subtle because it's proportional. It's not something I've found detrimental, quite the opposite it's beneficial, but I'm not using one of the heavier staining developers.

Ian

 

[Jed Freudenthal]

Jed, I can partly understand and agree with what you're saying but few Graded papers have direct MG/VC equivalents.

So if I took a stained and unstained negative and printed them both straight, no dodging, burning, developer controls etc on Graded and <G/VC papers of/at the same grade then yes I might well see some differences due to the stain. However if I then went on to make exhibition prints I could get very close with all combinations.

Ian

I took pyrogallol negatives with subtle highlights and detail in the shadows ( the critical part) and I was unable to print on graded paper and VC in a comparable way. [ the graded papers where Oriental, Kerntona, an several Forte Papers; VC in particular Forte and the new Adox MCC 110].
The differences between graded and VC were consistent.
I like the result; I just choose whatever is the best. If graded and VC would have been the same, what wouild it bring you? I think it comes from the stain, but what does it matter? The result is what counts.

Jed

 

[Nicholas Lindan]

The differences between graded and VC were consistent.

I think you will find much the same with unstained negatives.

When making the comparisons it is important to be as 'double blind' [not a good term in this context, I admit] as possible.

I mark the back of the paper with all the details: negative, paper, developers, filtration etc., etc. .... I wait several days before making any evaluation and only look at the front of the print. If I can't reliably sort the prints then there really isn't any difference in the printing methods being used.

I find differences that seem apparent in the darkroom disappear when prints are judged impartially.

* * *

On another point: Many 'graded' papers are in reality VC-style papers with multiple emulsions with overlapping HD curves. The contrast is fixed when the paper is made as the graded variants are made without green sensitizers.

A carefully made HD curve of a graded paper, especially when the local contrast is plotted, shows the characteristic contrast hump in the middle of the characteristic curve where the curves for the constituent emulsions overlap.

 

[fschifano]

Ctein noted that some VC papers have a sharpness problem caused by the near ultra-violet part of the image focusing at a slightly different plane than the green part. This seems to be an issue with enlarging lenses and, as far as I know, most modern, quality enlarging lenses focus the UV and visual parts of the spectrum at the same plane. Nevertheless, when I read that, I was happy I didn't have to test my enlarging lenses...

That may very well be true; but I think that, in practice, this characteristic is a non-issue for enlargers using tungsten or tungsten/halogen light sources. These lamps put out very little or no UV radiation. Any little UV radiation that might be present will be filtered out by the condenser glass or the light mixing box dependent upon the type of lamp house. The situation for those using cold cathode or florescent tubes as a light source will be different, but the other challenges of obtaining a full range of contrast values using these types of lamps with MG/VC papers outweighs this.

 

[RalphLambrecht]

... If graded and VC would have been the same, what wouild it bring you? I think it comes from the stain, but what does it matter? The result is what counts. ...

An accidental result does not count, and for a result not to be accidental, it's important to understand the way it was achieved. So, it does matter.

Anyway, I'm still confused. What is the claim? That stained negatives produce better highlight contrast with graded papers only? I find that interesting and like to get more info, because it could be very useful. So, let's put our thinking caps on and design a test to prove and measure the contribution.

 

[RalphLambrecht]

... When making the comparisons it is important to be as 'double blind' [not a good term in this context, I admit] as possible.

I mark the back of the paper with all the details: negative, paper, developers, filtration etc., etc. .... I wait several days before making any evaluation and only look at the front of the print. If I can't reliably sort the prints then there really isn't any difference in the printing methods being used.

I find differences that seem apparent in the darkroom disappear when prints are judged impartially. ...

Very true, and very sensible approach!

... A carefully made HD curve of a graded paper, especially when the local contrast is plotted, shows the characteristic contrast hump in the middle of the characteristic curve where the curves for the constituent emulsions overlap.

And I thought, the lack of a 'hump' was the big benefit of graded papers?

 

[Mark Crabtree]

One is setting exposure etc for the highlights then adjusting paper contrast grade to conrol the shadows, emphasis is on the highlights first.

The second is placing the emphasis on shadow detail and it's micro contrasts, then bringing the highlights under control.

The difference is in approach and while it may not be important in some images it may well affect choice of paper, development techniques and other controls etc in others.

Ian

Exposing for the shadows allows for an easy way to adjust highlights with a colorhead. You can then use the magenta knob as a highlight control without the need to make adjustments to the exposure time.

You do need to set your exposure for the darkest shadow tones for this to work well.

 

[RalphLambrecht]

One is setting exposure etc for the highlights then adjusting paper contrast grade to conrol the shadows, emphasis is on the highlights first.

The second is placing the emphasis on shadow detail and it's micro contrasts, then bringing the highlights under control.

The difference is in approach and while it may not be important in some images it may well affect choice of paper, development techniques and other controls etc in others.

Ian

I still see no difference.

Of course, there is a difference between 'exposing for the highlights and controlling shadows with contrast' vs 'exposing for the shadows and controlling highlights with contrast',

... but I see no difference between the two approaches you guys stated:


Mainecoonmaniac
... I print for my highlights and use the contrast grade to control the shadows.

Ian
... Often it's necessary to use contrast grade to control and open up the shadow detail, and printing controls to control the highlights.

In both cases shadows are controlled with contrast.

 

[Jed Freudenthal]

An accidental result does not count, and for a result not to be accidental, it's important to understand the way it was achieved. So, it does matter.

Anyway, I'm still confused. What is the claim? That stained negatives produce better highlight contrast with graded papers only? I find that interesting and like to get more info, because it could be very useful. So, let's put our thinking caps on and design a test to prove and measure the contribution.

I agree that will be interesting to know how results are achieved. But Ralph please tell me what question is to be answered and what data you need, and how they are going to be used, considering the data we now have of VC papers in the context of comparing graded versus VC papers. This may be the start of a comparative study. In the mean time, I follow the practical course of just using both graded and VC paper.

I am not claiming that stained negatives produce a better highlight contrast with graded paper. I say that highlights with pure diffuse reflection{ white clouds] produce a better highlight on graded paper, but highlights with a lot semispeculars[refections on water and leaves] are better on VC paper. This is just one of my selection criteria for graded or VC paper.

Jed

 

[RalphLambrecht]

Jed

How do you feel about Vlad's post #23? I like to test his statements there. If true, I can see lots of opportunities.

 

[Bill Burk]

I feel unqualified to join this conversation because don't use Pyro and I use graded paper.

But I see where this can go.

Test three negatives:
A. Developed in standard developer to specific CI.
B. Developed in Pyro until silver + stain combine to the same CI as A.
C. Developed in standard developer to a lower CI, comparable to silver image of the Pyro negative.

Print all three on Multigrade paper under Green light, then print all three under Blue light

Assertion: A certain amount of Green light passes through stain, effectively lowering the negative's CI through Green light. Stain blocks Blue light effectively, delivering full CI.

---

Expected supporting results:
Green light: A. B. C. can be sorted in order.
Blue light: A. B. indistinguishable.

Possible disproving results:
Green light: A. B. indistinguishable.

 

[Nicholas Lindan]

highlights with pure diffuse reflection [white clouds] produce a better highlight on graded paper, but highlights with a lot semispeculars[refections on water and leaves] are better on VC paper.

That is due to the nature of VC and G paper. The highlight contrast of VC paper is low - grade 00 - until grades 4 through 5. The reason is the contrast is made up of two HD curves (green sensitive and blue sensitive) that slide over each other as contrast is increased. It is only when the two curves are over each other that highlight contrast makes any significant change. The same reasoning applies to deep shadows.

This behavior of VC papers explains the popularity of using a #5 filter for burning highlights. With this technique the deep shadows are first held back and them burned back in with a #5 filter.

Again - reference the white paper on the Darkroom Automation web site: http://www.darkroomautomation.com/support/appnotevcworkings.pdf

The contrast change in VC paper takes place almost entirely in the midtones - and not very well at that, as it grows a spreading contrast hump in the middle of the HD curve.

Graded papers have higher or lower contrast along their entire HD curve. Or used to, as many modern 'graded' papers seem to be crypto-VC papers.

I think the preference noted above - VC for specular highlights, graded for diffuse - has to do with just this phenomena: hard specular highlights benefit from the low highlight contrast of VC to keep them from blowing out; soft diffuse highlights benefit from the greater highlight contrast of graded to bring out detail.

 

[Jed Freudenthal]

Ian, I'm not talking about overall contrast. Of course, if you develop your Pyrocat negatives to the same CI as your Rodinal ones, you'll print them all with the same VC filter.
I was talking about something else. Most papers have a toe and a shoulder. The toe means that contrast in the highlights is lower than in the midtones, and that's regardless of the contrast filter (or paper grade) used.
The stain filters blue light, and its density is proportional to silver density, which means that on a paper that's mostly sensitive to blue and much less to other colors it increases local contrast slightly. Because the stain is denser in the highlights, its effect is to counteract the paper's toe to some extent.
On VC papers the stain favours green over blue light, so local contrast in the highlights is lowered. Not only doesn't the stain counteract the toe, but it actually adds to it.

The effect is subtle, and only noticeable with certain subjects. Most negatives, be they stained or not, would probably print exactly the same on both kinds of papers. But when you happen to have an image with difficult highlights, where you struggle to retain fine detail in the highlights while at the same time keeping them as white as possible without blowing them out, then you might be able to do it a bit easier on graded paper. A good printer could probably get the same result on VC paper, but it would take more time and work.

Ralph is referring to the paper above. I think this is an excellent description of the effect of proportional stain. In fact, some time ago, I had in mind, to respond to this post. And, when I understand Ralph: if there is such an effect due to stain, there are a lot of opportunities.
This is exactly what I had in mind. Therefore, I made a HD pyrogallol film-developer with a maximum of proportional stain [ very low sulfite and restrainer]. Subjects with (semi)specular highlights and details in the shadow should show the effect of the stain best. I made a comparative test by printing on graded papers as well as VC papers. And the result was a significant difference between graded paper and VC paper.
The amount of stain will depend on the developer used. Therefore the effect might be less when other film developers are used.
The pyrogallol stain has also other properties on the image quality of the print. A twenty or thirty years ago, I made a test on this subject. At that time some people wanted to remove the stain ( there was a recipe to do just that). I made a duplicate negative, and removed the stain from one of them. I did not like the image quality of the negative from which the stain has been removed. Therefore, I never repeated this stain removal. Apparently, the optical quality is influenced when the absorbed oxidized pyrogallol molecules are removed from the silver crystals. The adsorbed oxidized pyrogallol molecules may have a diffusive optical character.

Jed

 

[RalphLambrecht]

I think Bill's proposal is worth trying.

 

[RalphLambrecht]

... The contrast change in VC paper takes place almost entirely in the midtones - and not very well at that, as it grows a spreading contrast hump in the middle of the HD curve. ...

Nicholas is making an extremely valid point. Could the effect described be almost entirely related to the characteristic difference between fixed vs variable-contrast papers and has little or nothing to do with stained negatives? It's possible. We really need a test to quantify the effect of staining negatives on highlight contrast.

 

[Ian Grant]

There's been quite a few tests and articles, a quick search turns up this one from 1999, but I seem to remember something more recent, here on Unblinking Eye.

Ian

 

[Jed Freudenthal]

That is due to the nature of VC and G paper. The highlight contrast of VC paper is low - grade 00 - until grades 4 through 5. The reason is the contrast is made up of two HD curves (green sensitive and blue sensitive) that slide over each other as contrast is increased. It is only when the two curves are over each other that highlight contrast makes any significant change. The same reasoning applies to deep shadows.
I l.

I cannot follow your reasoning, but that may be my problem.

My reasoning is the following: the photographic process requires a compression in the highlights as well as the shadows, The problem is how to deal with the highlight compression when we focus our attention on the highlights.
We can then distinguish between 100% diffuse reflection, like white clouds, nebulous areas etc. In this case the differences in luminosity are small, and the range to be compressed is limited. For a good representation, a high modulation transfer for the highlight region will be required. That can be found in graded paper. When we have semi-speculars, the luminosity range is large and a lower modulation transfer ( and HD) will absorb this better. And this is what we find in a stained pyrogallol negative with VC paper.
I approach this problem from the modulation transfer, because the modulation transfer is meant to describe image quality. And in this case, the modulation transfer of the high spatial frequencies appear to be most essential. And a pyrogallol developer is strong in the high spatial frequencies ( textures). Then one can really see the power of modern lenses. To demonstrate that I have teststrips of 16x20" and square meter prints.

Jed

 

[RalphLambrecht]

There's been quite a few tests and articles, a quick search turns up this one from 1999, but I seem to remember something more recent, here on Unblinking Eye.

Ian

I'm missing the straight comparison. Sandy compares visual to blue-channel densitometer readings with stained negatives. I'll try if I can see a difference between the two with 'normal' negatives as well. I wonder how a pink TMax would compare?

 

[Ian Grant]

There's a comparison of Tmax 400 in D76 and a Pyro dev in the first link, which was a View Camera magazine article, this is a better version.

Ian

 

[John Bond]

One of the problems with understanding what happens with stained negatives is knowing how much of a contribution comes from the proportional stain and how much from the generalized stain and how this relates to development time. Increasing development time increases highlight density (steeper characteristic curve of the negative) but also increases proportional stain and generalized stain. The proportional stain has more effect in the highlights. The generalized stain effects the entire curve. I do not know this for a fact, and please correct me if I am wrong, but I have the sense that increased development time gives more and more generalized stain to the point that the generalized stain begins to dominate in its effects. This offsets some of the increased contrast from longer development and also exposes the VC paper to more yellow with the lumpy characteristic curve of lower contrast filtration. With less development, there is less generalized stain and proportional stain dominates resulting in a more prominent shoulder. Increasing overall contrast can be achieved by higher contrast filters which avoids the lumpy curves.

Any test we come up with has to distinguish how much effect comes from proportional stain and how much from generalized stain.

 

[RalphLambrecht]

There's a comparison of Tmax 400 in D76 and a Pyro dev in the first link, which was a View Camera magazine article, this is a better version.

Ian

Thanks. The test data presented is limited to negative densities, but judging by this data alone, there would be no difference in prints made from either negative.

 

[RalphLambrecht]

... Any test we come up with has to distinguish how much effect comes from proportional stain and how much from generalized stain.

Agreed, but it's a second step. First, let's see if the advertised effect even exists.