Doom, Gloom and Reality

gainer · May 29, 2005

I have to agree with the statement that printing papers are NOT all made with the same H&D curve shape. Somewhere I have a Kodak publication with plots of curves for all the papers Kodak made years ago. They differ greatly. The curve shape alone may make a considerable difference in the rendering of a given subject. If this were not true, we would not tout our favorite developers for the shape they give the H&D curve of the negative. We will use different developers for landscapes than for product shots or portraits.

It may be that an expert printer can make any paper look the same as any other paper, but with how much work?

Photo Engineer · May 29, 2005

I guess I have to agree with Gainer - to a point. It should be obvious that a contrast 2 paper has a different curve shape than a contrast 3 paper. I thought that was obvious.

Also, Ilford papers differ from Kodak papers in the lower and upper scale due to the aims established by the company, but the mid scale for 2 grade papers (even VC papers of the same grade) should be the same. Contrast grade is an ANSI standard and is adhered to by all manufacturers. (or they are supposed to anyway)

But that is as far as I can agree. I felt that the points above were obvious in my reasoning. That is, I was not implying that a contact grade 3 was equal to an enlarging grade 2. Nor was I implying that an Ilford grade 2 was equal to a Kodak grade 2 except in the mid scale where contrast is measured.

So, a Kodak contact grade 2 paper should be equal to a Kodak enlarging grade 2 paper and the same would hold true for Ilford albeit the lower and upper scale between those manufacturers would differ slightly.

Blacks should have about the same tone, and so should browns within the products of a given manufacturer. A given manufacturer uses the same chemicals in both enlarging and contact papers.

Therefore to be specific, a Kodak grade 3 paper should be of the same curve shape if enlarging paper or contact paper, provided both are the same tone of image. The same would be true of Ilford papers or Agfa papers. Is that specific enough?

Manufacturers cannot have emulsions, chemicals and aims for every single product. They try to keep things as simple as possible for inventory purposes.

And, in any event, the user has a huge range of curves possible with developers and with VC papers, with split printing (even with contacts if he / she is adept enough).

PE

gainer · May 30, 2005

When we speak of curve shapes being the same or different, we should not include magnitude. That is, the curve shape of a grade 2 paper may be the same as the curve shape of a grade 3 0r 4 if you match the ends of the curves by multiplying by a constant. That is more likely to happen if the emulsions of the two grades are of the same type, I think. All bets are off with regard to VC papers. Chloride and bromide papers generally have different shapes as well as different responses to degree of development.

The contrast grade of a paper is determined by the end points of the curve. Two papers may have the same nominal contrast with very different midtone shapes. I can make two "straight" prints on different papers that have the same shadow and highlight values but which are very different in appearance.

The test of the truth of that statement will have to be done as one tests the quality of food or beverages. The observer must make a judgement without knowing what is being judged.

Whether we can or cannot get along with one type of paper by one manufacturer, we will find a lot of photographers crying when their favorite paper goes off the market. We have already seen it happen.

Photo Engineer · May 30, 2005

Mr Gainer, your description of the measure of contrast in paper is wrong, I'm sorry to say. The contrast is measured by the slope of the straight line portion of the curve done normally at a density of 1.0. The toe and shoulder vary according to specs determined by the individual manufacturer but remain rather constant between paper types of the same contrast grade.

Therefore, two papers with different contrasts have different midtone slopes, and different toe and shoulder shapes. This applies mainly to black and white materials. With color, where there is no stated contrast grade, the apparent grades are adjusted by manipulation of the mid scale and the toe and shoulder within a very narrow limit.

An excellent description of this for black and white papers is found in Dickerson and Zawadski, Photo Techniques March/April 2005, Page 19. The graphs illustrate my point exactly. The authors in this case show the mid tone pivot point matched at a density of about 0.7. Please note that they describe a poor VC paper, and it appears to be behaving somewhat as you describe, ie varying in the toe and shoulder while keeping the mid scale more nearly constant.

I agree completely with your last paragraph.

PE

gainer · May 31, 2005

Perhaps I should have stated my case in different terms. Two papers with the same mid tone slopes may have very different exposures at Dmax and Dmin, just as films may have long or short toes and rounded or sharp shoulders. In printing, we use both toe and shoulder. If you print for the accent blacks and clean whites, you will get different looking prints with different papers. If you print to make, say, Zones 3 through 7 the same, you will have very different looking prints. These differences are not always easy to correct.

Photo Engineer · May 31, 2005

Mr. Gainer, well said. I agree for with the following qualification. If you remain within a given manufacturers products such as Ilford, then there is a great probability that all grade 2 papers (contact and enlarging both) will have the same toe and shoulder. This is due to the nature of the definition of the aim and physical and chemcial laws coupled with the coating process. If you use a Kodak product with the same grade, the mid scale will (must?) be the same due to the ANSI definition of 'grade 2', but the toe and shoulder may differ due to those same physical and chemical laws accouting for the manufacturing process and chemical differences between manufacturers.

Inventory and testing procedures within a given manufacturer lead to this sort of behavior. They try to use common chemicals across products for similar purposes, and these tend to lead to the same toe and shoulder curves.

PE

Earl Dunbar · May 31, 2005

Ian Grant said:
Quite right Isaac

In fact the Agfa warm toned paper I used changed quite significantly when they had to remove the Cadmiun about 16 or 17 years ago, (Record Rapid possibly called Portriga in the US). Then the paper was replaced by VC Classic. So change is forced upon us by manufacturers.

We are talking fine nuances in tones and colours with different papers and there are various ways of altering these anyway.

Anyway my point was that if some popular papers disappear other manufactures will be asked to fill the gap and make a similar product.

I started this thread because the doom and gloom of companies possibly ceasing trading is actually going to boost the sales of the smaller companies who remain in the market if it happens.

Ian

Sorry to be "late" to reply to this post, but it did trigger something.

First of all, thanks for the references to Record Rapid and Portriga; brought back some pleasant memories. In Canada and the Excited States, those were different papers. I really, really liked Record Rapid. I didn't know it was changed (or vanished) due to cadmium being removed. Cadmium is nasty stuff, so I sadly agree with its demise. Portriga was a different animal, at least in my experience. I could never learn to love it, but did have spasmodic fits of joy with it. As its name infers, it was good for portraits and sometimes I was able to make a good portrait negative and it printed well on Portriga. Certain landscapes worked well, too.

I think the thing that bothers a lot of folks though is not that products come and go, but that given the devotion and effort many of us put in to testing, calibrating and "learning" a film, paper, developer, process, etc., it just gets so very tiring trying to keep up. This frustration is exacerbated by the fact that the changes are often so "unnecessary" given the fact that the changes comes from market conditions (i.e. digital juggernaut) that is currently giving us products that are inferior for the type of work we do.

There is a Weston exhibit here at the George Eastman House this Spring and Summer. I'm going to go see it and take a look at some of the papers I'll never be able to use. Thank goodness the images will be glorious enough to dull the pain.

Earl

gainer · May 31, 2005

Photo Engineer said:
Mr. Gainer, well said. I agree for with the following qualification. If you remain within a given manufacturers products such as Ilford, then there is a great probability that all grade 2 papers (contact and enlarging both) will have the same toe and shoulder. This is due to the nature of the definition of the aim and physical and chemcial laws coupled with the coating process. If you use a Kodak product with the same grade, the mid scale will (must?) be the same due to the ANSI definition of 'grade 2', but the toe and shoulder may differ due to those same physical and chemical laws accouting for the manufacturing process and chemical differences between manufacturers.

Inventory and testing procedures within a given manufacturer lead to this sort of behavior. They try to use common chemicals across products for similar purposes, and these tend to lead to the same toe and shoulder curves.

PE

Not to be contentious but hoping to be informative, I found my copy of the 1982 Kodak publication. "Quality Enlarging with Kodak B/W Papers". I quote from the portion dealing with use of spot metering:

"METERING FOR PAPER CONTRAST

By measurement of a diffuse highlight area and a shadow area of the negative image projected onto the easel, and finding the difference, the proper contrast of paper for the image can be found.

When the log-illuminance range of the image matches the log-exposure range of the paper, the paper will print the image with acceptable contrast."

There is no mention in this publication of the use of the slope of the linear part of the characteristic curve as a measure of contrast grade. The log-exposure ranges of the various paper grades are expressed as the difference between the values required to produce 0.9 Dmax and 0.04. It is quite obvious from the diagrams that these diffuse highlight and shadow points are well out on the non-linear part of the curve.

An examination of the characteristic curves shows that in fact a number of the papers have no appreciable straight portion. As of 1982, the toe and shoulder gradations of these papers are not any more likely to be like one another than to be like the curves of another manufacturer. The curves for AZO show why the AZO afficionados prefer grade 3 over grade 2. The difference in curve shape is rather large, as is the difference in Dmax.

The papers available now may be much more alike. If they were all alike, there would be no need for more than one general type. I am sure that if the manufacturers could lead us in that direction, it would be an economy for them. Perhaps it would not be such a bad thing for us, but then we might say the same thing about the move from silver to digital. Even so, we will still cry about it.

I'm going on 78 years of age, so I hope you understand why I wax nostalgic.

Photo Engineer · May 31, 2005

Mr Gainer, I never said papers were alike.

I said basically that you could find a contact grade 2 paper and an enlarging grade 2 paper that would be a very close match if not identical if made by the same manufacturer. I gave reasons to support my statement, and a reference to support it in part. I would go as far as saying that you could find a close, but not identical match across manufacturers with the same contrast grade paper.

I suggest you read that reference and look at the curves. There is in fact a considerable straight line portion to papers. The method you describe is an on-easel method of getting a good exposure, but not appropriate within the context of what we are discussing. We are trying to cope with the vanishing supply of contact papers, and whether an enlarging paper could suffice. I say yes, with the proper paper and exposure compensation, an enlarging paper can work.

And, btw, the very lack of a long straight line portion in many manufacturers papers does not make them good or bad, but it does make it essential to have a definition for measuring the true contrast of a paper. You know that this is basically delta density / delta Log E, and this is taken at some arbitrary straight portion of the curve between density ~0.6 and ~1.2. The ANSI contrast numbers are derived from this figure and the toe and shoulder of the paper contribute to making or breaking the overall image making capability of a paper.

I have given my reasoning and a supportive reference to counter your objections. I suggest that all interested read the article. It is quite informative.

PE

sanking · May 31, 2005

gainer said:
An examination of the characteristic curves shows that in fact a number of the papers have no appreciable straight portion. As of 1982, the toe and shoulder gradations of these papers are not any more likely to be like one another than to be like the curves of another manufacturer. The curves for AZO show why the AZO afficionados prefer grade 3 over grade 2. The difference in curve shape is rather large, as is the difference in Dmax.

This is certainly true. Papers vary considerably both in the shape of the toe and shoulder as well as in the straight line portion. If there are "family" characteristics by manufacturer I have not observed it.

With the specific case of AZO, the developer used also makes a lot of difference. The shape of an AZO 2 curve in Dektol is very different from the same paper in Amidol or Ansco 130. There are examples of this on the AZO forum.

Sandy

Photo Engineer · May 31, 2005

Gentlemen, to see what I am talking about, I suggest that you go here -

http://www.kodak.com/global/en/professional/support/techPubs/g10/f009_0104ac.gif

and here -

http://www.kodak.com/global/en/professional/support/techPubs/g27/f009_0042ac.gif

Except for Dmax, both papers (contact and enlarging) have the same overall charactereistic curve including mid scale and toe. Print them out and superimpose them. If you look at more curves you will see the similarity or near identical nature of the different papers at the same contrast grade.

Indeed, Sandy is correct, developer is vital in the overall curve shape and I would like to add that the surface is also vital in the upper scale. A matte surface gives lower dmax than a glossy surface. In this particular case though, the contact and enlarging papers are identical up to the dmax region but diverge even though they are both supposedly glossy materials.

If you make the comparisons, as I have, you will find that over and over you will find this equivalence between papers as long as the contrast grades are identical. To illustrate this, you might look at the polycontrast IV curves and compare them to the two I posted above.

PE

Jorge · May 31, 2005

Uh? I am sorry but these two curves are no where near the same. They appear to have the same slope, and a similar toe, but the shoulder is defintily different. From these curves it suggests that panalure has better separation in the highlights than azo, I dont know if this is true or not, but they are definitly not the same.....Given that well separated highlights are an important part of print making some, or at least me, might conclude that panalure is a better paper for their style than azo and would be upset if it was/is gone......If your argument is that it does not matter what paper is used we can always "fit" a different paper, IMO your curves prove differently.

Photo Engineer · May 31, 2005

Jorge;

I picked azo and panalure as grade 2 examples and stated in my post that the dmax values differed. You can see that much difference between glossy and matte.

I also referred you to the other curves there which show great similarity between different papers of the same grade. And yes, the panalure would probably be better than the azo paper given the curve, which was another point that I hoped people would pick up.

The real point is that there are a myriad of papers out there with identical curve shapes at the same contrast grade or that can be made to match by varying developer. Go look at some of the curves and read the Dickerson Zawadski article.

And again, the toe and mid scale are virtually identical across enlarging and contact papers in this example, not vastly different as one would believe from the other posts.

Another point might be that Azo isn't that great of a paper.

PE

avandesande · May 31, 2005

PE all these things have been discussed to death in the past. The developer is important.
http://www.michaelandpaula.com/mp/DJ_curves_article.htm

WarEaglemtn · May 31, 2005

"I didn't know it was changed (or vanished) due to cadmium being removed. Cadmium is nasty stuff, so I sadly agree with its demise."

So is selenium but we still use it.

I can still get cadmium red paints for brushwork and even though it was discontinued for awhile those who make these paints realized 'good enough' wasn't & started making the paint with cadmium it again.

I don't see a real problem with having cadmium in a line of photo papers as nothing that 'replaced' them is doing the job.

gainer · May 31, 2005

Photo Engineer said:
Mr Gainer, I never said papers were alike.

I said basically that you could find a contact grade 2 paper and an enlarging grade 2 paper that would be a very close match if not identical if made by the same manufacturer. I gave reasons to support my statement, and a reference to support it in part. I would go as far as saying that you could find a close, but not identical match across manufacturers with the same contrast grade paper.

PE

I doubt that answer satisfies the complaint of those who mourn the passing of their favorite papers. It may be that you can find two papers, contact and enlarging, that have identical characteristic curve shapes, but it also might be true that you would not want to use either one.

Nominal contrast grade is not the only governing factor in choosing an optimimal paper. Nominal contrast grade is NOT determined by the slope of the straight line part of the curve, or at least was not so determined in 1982. There are some curves in the reference I quoted that have almost no straight part. The slope varies all along the curve. A grade 2 paper had a log-exposure range between 1.05 and 1.2, over which range reflection density varied from 0.04 to 90% of Dmax. The prints of the same negative on any paper that fitted that definition of grade 2 would have the same Dmax and Dmin, but might look quite different to a discerning viewer.

Mark Layne · May 31, 2005

There is no paper out there that can give results identical to Azo, or Portriga or Kentona for that matter.
An English grade 2 is not the same as an American grade 2

Mark

Jorge · May 31, 2005

Photo Engineer said:
Jorge;

The real point is that there are a myriad of papers out there with identical curve shapes at the same contrast grade or that can be made to match by varying developer. Go look at some of the curves and read the Dickerson Zawadski article.

And again, the toe and mid scale are virtually identical across enlarging and contact papers in this example, not vastly different as one would believe from the other posts.

Another point might be that Azo isn't that great of a paper.

PE

Here is where I disagree with you, close enough is not identical. The curves you presented while seemingly identical in the middle tones, have an important difference, that difference might cause you to develop and print in a specific manner to give you the results you want. Lets use your panalure example, one could conceivably develop the negative to higher contrast to take advantage of the apparent better highlight separation. When you do this, the middle tones in the negative are also affected to some degree and they in turn will show this in the paper.. This is a special relationship that would most likely could only be found by printing with this paper, and no matter how much adjustment you make with a different paper, the special caracteristics of the shoulder in this paper might make it unique for some.

While looking at curves is a good indication of the paper's behavior, the print tells the tale. I am not an azo printer and I happen to agree with you in 99% of the time, but let me tell you in the hands of someone who knows how to use it, it is capable of some of the most beautiful prints I have ever seen. Wareaglemtn sent me a print that is absolutely exquisite, I dont know that the same results could have been acheived with a different paper, and I suspect most likely they could not.

phfitz · Jun 1, 2005

Hi there,

Did the world stop spinning when they stopped:

Illustrator's Azo?
Medalist?
Opal?
Defender?
Ansco?

Maybe they will all come back when China and India get up to speed and there is a market for them. I think Aggie is right, the doom and gloom sounds like PMS.

Darwin's rule applies:
the first to adapt wins

The new products will be different but just as amazing. It should be an adventure to play with them.

Kirk Keyes · Jun 1, 2005

Photo Engineer said:
Just a note to pyrogallol and wareagle above.

Ron - side note - How do you know his name is pyrogallol - maybe he's 1,2,4 and not 1,2,3?

gainer · Jun 1, 2005

"And again, the toe and mid scale are virtually identical across enlarging and contact papers in this example, not vastly different as one would believe from the other posts."

But the shoulder is where shadow contrast appears in the print. Compare the sketch of AZO you supplied with this from Kodak.

Photo Engineer · Jun 1, 2005

Mr Gainer, I am not sure what the family of curves you show above represents. There are no labels on them to tell me what they are. However, I do agree that development is crucial to obtaining the optimum result from any photographic material.

I would like to point out that Azo is deficient in upper scale density and latitude, and anything (developer or another paper) would likely improve this condition, and that is why I posted the two examples I did. I could have included some of the others, but Kodak saw fit to plot them with different scales on the x and y axis and therefore made it much more difficult for direct comparison.

I think that the point is that a good painter does not need one brand of canvas, brush or paint to turn out a good picture. The painter needs to be a good artist! The same is true in photography. We will all move on to new products and new techniques.

I might add that replotting some of those characteristic curves of Kodak's on the same scale might be of use to those interested in understanding the situation that I'm trying to convey. It is simply that two products from the same manufacturer, at the same contrast grade will have the same mid scale slope, and can have identical toe and shoulder. The example that I gave above shows the identical slope and toe, the shoulders differ. The one with the shorter latitude can give inferior results due to the shorter tone scale. It was chosen to illustrate just that point and also because the others were plotted to a different scale. Of course, variations in development will change this relationship, but then it isn't grade 2 anymore then is it.

PE

gainer · Jun 1, 2005

The scales are logarithmic and are the same for all characteristic curves I have ever seen when it comes to representing the shape of the curves. The curves represent the different grades of AZO available in 1982. The solid curve is grade 2. If you look at the 0.g feflection density level, the curves are in order left to right: grades 1, 2, 3, 4, 5.

If winning this battle means convincing an AZO aficianado that AZO is not needed, you must know by now you will never win. If you are trying charitably to ease the pain of their loss, you will find them inconsolable. A fellow once saw me distressed over something and said "Cheer up. Things could be worse." So I cheered up, and sure enough, he was right. Things got worse.

Jorge · Jun 1, 2005

Cheer up. Things could be worse." So I cheered up, and sure enough, he was right. Things got worse.

LOL......

gainer · Jun 1, 2005

I goofed. "0.g feflection density level" should have read "0.6 reflection density level. Also, all the curves in that Kodak publication were plotted to the same scale. I didn't show all of them, but they include Velox, Ektalure, Ektamatic, Kodabrome II, Kodabromide, Medalist, Mural, Panalure, Polycontrast, Polycontrast Rapid, Portrait Proof, and Polycontrast Rapid II.

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