"Optimized for digital" color papers...only legend?

BetterSense · Mar 22, 2011

I want to do some color printing just because I'm worried that materials won't be available in the coming years. I understand that Kodak's paper is only available in rolls right now, whereas Fuji has some paper available in sheets (does anyone else make color paper?).

On top of the Kodak paper being available in only rolls, I have heard that color paper in general is optimized for digital printing. But I don't understand what this means. What is different about a paper optimized for digital printing vs. enlarging? How do digital printing machines work? Don't they still use R G B light? Why wouldn't they just design the printing machines to work like a negative? How big of an issue is this supposed "digital optimization" for the darkroom worker? How does it affect film choice? Overall, how much worse is it now compared to the absolute heyday of color printing (which I'm guessing was the late 90s)?

hrst · Mar 22, 2011

BetterSense said:
I have heard that color paper in general is optimized for digital printing. But I don't understand what this means. What is different about a paper optimized for digital printing vs. enlarging? How do digital printing machines work? Don't they still use R G B light?

"Digital optimization" simply means that they can slack in some of the design rules and use that effort towards other goals.

In optical enlarging, the curves for R, G, B must match in contrast and curve shape so neutral appears neutral in shadows, midtones and highlights. In a "digital" paper, the contrast (and curve shape) can be modified digitally, so this design parameter is not needed for paper. Also, it is quite irrelevant what the contrast is. It can be modified in printing.

Thus, a paper that is "optimized for digital exposure only" -- or, not optimized for optical enlarging, may have non-optimal contrast, and some contrast mismatch in curves, causing color crossover. How bad this is -- the only way is to test. Some people say it's usable.

Read the new Endura VC datasheet from Kodak. It says that in optical enlarging, contrast is high and neutrals appear cyan if balanced for skin tones.

BetterSense · Mar 22, 2011

I printed the same image on both Supra Endura papers and posted the results here somewhere. The VC digital version showed a slightly different color balance and slightly more contrast.

What is the VC digital version? Does VC mean variable contrast? Is there another non-digital version?

MattKing · Mar 22, 2011

As I understand it, most (all?) of the machines that print from digital files are set up to provide very short, high intensity exposures. The light sources used may also be more similar to electronic flash than incandescent or halogen light. So being "optimized for digital printing" actually means being optimized for the print times and light sources found in digital printers.

MattKing · Mar 22, 2011

Is KODAK PROFESSIONAL ULTRA ENDURA High Definition Paper available, and has anyone used it?

The data sheets indicate that it is optimized for both digital and optical printing. It is only available in F (glossy) surface.

Photo Engineer · Mar 22, 2011

Digital papers are optimized for high intensity short exposures. They are also optimized for printing via scanning the paper with the light in lines rather than a single overall exposure. To do this, the reciprocity and some other factors had to be changed with regard to this new method of exposure.

It is indeed a new emulsion set.

PE

John Shriver · Mar 22, 2011

The digital papers also don't have the different sensitivity for each of the three emulsions, they have the same sensitivity. So you need to use drastically different color filtering for optical exposure, since they don't compensate for the orange mask.

They are also very wide gamut, such that the C, Y, and M dyes are very far out in the color space. That's because the wider the gamut of your paper, the wider selection of colors you can actually have it come out. This means that exposed optically, they wind up being high color saturation.

The wide gamut is mostly important for labs taking in color images in Adobe RGB and other wide color spaces. If they only take in images in sRGB, the older papers with less gamut will do fine, since those color spaces can't really represent the wide gamut.

Photo Engineer · Mar 22, 2011

John Shriver said:
The digital papers also don't have the different sensitivity for each of the three emulsions, they have the same sensitivity. So you need to use drastically different color filtering for optical exposure, since they don't compensate for the orange mask.

They are also very wide gamut, such that the C, Y, and M dyes are very far out in the color space. That's because the wider the gamut of your paper, the wider selection of colors you can actually have it come out. This means that exposed optically, they wind up being high color saturation.

The wide gamut is mostly important for labs taking in color images in Adobe RGB and other wide color spaces. If they only take in images in sRGB, the older papers with less gamut will do fine, since those color spaces can't really represent the wide gamut.

John;

I'm sorry, but your post is absolute nonsense to me. I cannot figure out a word of it at all.

The paper has just about the same sensitivity and most other properties except for reciprocity and latent image keeping among others.

BTW, I had lunch a year or so ago with the head of the project and he explained it all to me. Who explained this all to you?

Again, sorry.

PE

hrst · Mar 23, 2011

John,
You can also see the datasheets that are available on Kodak website, and they show that the RGB sensitivities are very close if not the same as in the old product. That's definitely not a problem. Filter pack changes are minor.

Go to www.kodak.com/go/professional, product information, papers. See spectral sensitivity curves.

The sensitivities are as they are for technical reasons in paper manufacture (the layer order & lack of yellow filter layer, PE can definitely explain more), and it "happens" to compensate for orange mask, too.

Photo Engineer · Mar 23, 2011

Well, as I have said, if you consider red speed = 0, then green = about 0.8 log E faster and blue = about 1.2 log E faster. This balance is needed for several reasons.

1. It makes it tungsten balanced
2. It compensates for the mask
3. It removes the blue sensitivity of the R/G layers from the image

The Yellow layer is on the bottom, for reasons of dye stability and there is no yellow filter layer in the coating for this reason.

These have not changed for over 50 years. The changes for digital printing are those I mentioned earlier regarding the ability to print with the high intensity scanning printers.

PE

EdSawyer · Mar 23, 2011

Would additive printing via RGB (say with a Minolta Beseler 45A head) be able to accommodate using "digital" RA-4 paper? It can vary the exposure on a per-color basis easily, using the additive colors. It also powers the head via electronic flash, so the short/high intensity side of things might be covered a bit too?

Just a thought.

-Ed

Photo Engineer · Mar 23, 2011

It might improve color, but IDK for sure.

The problem is that it might increase individual exposure times and worsen the reciprocity situation. This paper needs very short high intensity exposures.

PE

hrst · Mar 23, 2011

EdSawyer said:
Would additive printing via RGB (say with a Minolta Beseler 45A head) be able to accommodate using "digital" RA-4 paper? It can vary the exposure on a per-color basis easily, using the additive colors.

What? You can vary the exposure on a per-color basis just as easily with subtractive dichroic enlarger heads. There might be a small difference in spectral response but I think you have understood something fundamentally wrong.

My point earlier was that there might be a need to adjust CONTRAST per color. It cannot be done by modifying light. You have to make separation negatives and adjust their processing parameters to do that.

Maybe, if the crossover is mostly in highlights and is very slight, color-filtered preflash could help.

But, OTOH, some people say that the color crossover really is not a problem. If the overall contrast is too high, it can be handled with methods given in (there was a url link here which no longer exists) .

John Shriver · Mar 23, 2011

Flibber, flubber, you're right. Dang! I'd somehow imprinted on my mind that the characteristic curves of RA-4 papers were offset like the characteristic curves of C-41 films, to complement that offset. Instead it must the "default filter pack" that cancels out the offset of the C-41 curves. My apologies for having something so wrong so firmly wedged in my mind! So you can print with the same filter packs on this paper.

However, right on the promo page for Supra Endura VC Digital, it says "expanded color gamut". To me, that means that if you plotted the positions of the cyan, yellow, and magenta dyes on this paper, they would form a larger triangle on the CIE Chromacity Chart. Closer to the outer boundary, which is the "spectral" locus. That's what larger gamut means when you're shopping for a printing system or a monitor. (Just that the monitor triangle is red, green, and blue.) Am I interpreting this correctly? It's certainly what I would want a "wide gamut" printing system to do.

The ink-jet vendors have been working on wider gamut for years. They are Kodak's real competition, not Fuji. So Kodak has (properly) responded with wider gamut RA-4 papers for digital printing. Good move in my opinion. (Kodak has had the wrong competition or market in mind too many times in the last 20 years.)

Unfortunately, Kodak only gives the "spectral dye density" curves for papers. They don't give the CIE coordinates of the three dyes. That would be the way to see what the gamut of each paper it. However, looking at those curves for Supra Endura VC Digital (E-4042) and Portra Endura (E-4021), the ones for the VC paper look to more "sharp cutting", that is narrower. I suspect that indicates that the dyes in VC are closer to "spectral".

(I'm painfully aware of the quirks of wide-gamut devices, because I use an HP LP2745w monitor, which has a gamut the same as Adobe RGB, rather than the much smaller sRGB monitor most LCD monitors support. Great when color management works, a headache for non-color-managed applications, or broken ones like Firefox 3.x, which only properly color manages images with ICC V2 profiles, but not ICC V4 profiles.)

hrst · Mar 23, 2011

I think you are right. Sharper-cutting dyes indeed create wider gamut (of course if the absorbance peak is at the correct wavelength). There might be a drawback; under some cheap fluorescent lights, the sharper dyes might look worse if they don't match with the peaks in the light's spectrum. I don't know if this is a real problem, just speculation. I have however seen problems under some fluorescent lights with standard Supra Endura. Prints shift in magenta-green depending on light source more than "neutral" paper or grey card appears to shift.

Note that the final dyes and the spectral sensitization dyes do not need to have any connection with each other. So, the spectral sensitization dyes should be selected to match the RGB lasers used in digital exposure, or the C-41 film dye absorbance peaks, but luckily, I think that the lasers were matched first at the time the paper was optimized for optical printing only, so there's no need to change this anymore.

MattKing · Mar 24, 2011

Adjust through developer chemistry?

Photo Engineer said:
Digital papers are optimized for high intensity short exposures. They are also optimized for printing via scanning the paper with the light in lines rather than a single overall exposure. To do this, the reciprocity and some other factors had to be changed with regard to this new method of exposure.

It is indeed a new emulsion set.

PE

PE:

Just wondering here.

Could the response of these digital papers be made more suitable for optical printing by adjusting the development chemistry?

I envision an additive for the developer (no doubt with a difficult to locate Kodak catalogue number ) which is intended to be used only by photographers and labs who are only printing optically. The now main-stream labs that print digitally wouldn't use it, but the individual photographers and labs with older equipment could.

Photo Engineer · Mar 24, 2011

Matt;

AFAIK, there is no such thing. Sorry. Reformulation of the entire developer might help, but that would take a lot of work and may not yield anything useful.

PE

GeorgK · Mar 27, 2011

From personal experience:
I tried to print on "Kodak Metallic Endura" (a digital paper) a few weeks ago. These were landscapes with blue sky, green and brown grass, grey rocks and some trees. The results were absolutely un-usable. If rocks and clouds were neutral, the sky was pure cyan; when the sky was o.k., rocks and clouds were pink. The brown of the trees was awful. Parallel prints on Supra Endura ("analog" paper) were perfect (BTW, is was Ektar 100 in MF)
In clear words: These were not minor color shifts, but the colors were really way off.
Conclusion: "Digital" paper might be usable with genres where color fidelity in all colors is not necessary, like (mostly) monochrome sceneries, some product photos, or experimental work. But for anything with a palette of "natural" colors, they are useless.
In my experience, many amateurs have extremly low standards when it comes to judging own prints (it's like "my child"). This might be where the positive opinions on the web are deriving from.
For me, when "analog" papers are gone, the traditional color darkroom will be history.

Georg

hpulley · Mar 28, 2011

Used to do this in the '80s with help. Just getting back into it now (and by myself), hope I didn't pick the wrong time! Should I buy all the Endura I can afford??? From labs all I've received for years and years is Fuji Crystal Archive. IIRC I used to get Kodak Royal paper at labs before they went to Kodak Royal Digital paper.

hrst · Mar 28, 2011

There is nothing wrong with the current "plain" Fuji Crystal Archive. It is optimized for both digital and optical exposure and is still available. Of course, if you prefer Kodak Supra Endura, stock it while you can.

frotog · Mar 30, 2011

hpulley said:
Used to do this in the '80s with help. Just getting back into it now (and by myself), hope I didn't pick the wrong time! Should I buy all the Endura I can afford??? From labs all I've received for years and years is Fuji Crystal Archive. IIRC I used to get Kodak Royal paper at labs before they went to Kodak Royal Digital paper.

Probably not a good idea seeing as how most of what's still out there has already expired. FYI - the last production run has a exp. date of 5/2011. If you can find it (good luck) and freeze it you're good for the next year and change.

frotog · Mar 30, 2011

Conclusion: "Digital" paper might be usable with genres where color fidelity in all colors is not necessary, like (mostly) monochrome sceneries, some product photos, or experimental work. But for anything with a palette of "natural" colors, they are useless.
In my experience, many amateurs have extremly low standards when it comes to judging own prints (it's like "my child"). This might be where the positive opinions on the web are deriving from.
For me, when "analog" papers are gone, the traditional color darkroom will be history.

Georg[/QUOTE]

Even the old supra endura from ten years ago (as well as portra endura and ultra endura) was designed for digital exposure. I imagine that one of the design constraints was to make that paper compatible w/ optical enlargements as there were labs that had not switched over the laser light exposure.

Color printers will recall how the emulsion in the endura line underwent several changes in the years before VC. With every new emulsion color balance for neutral became increasingly difficult to obtain. Most vexing was the way these papers rendered blues - a much narrower palette of blues compared to the non-endura line of papers.

Of course the most recent wave of c-paper (Supra VC et al) was not at all designed for optical enlargement but, as many here have discovered for themselves and despite your proclamation that the color drkrm. is history, it works.

Photo Engineer · Mar 30, 2011

Way back in the 60s and 70s, when we had a problem with cyan fog or a soft cyan toe, we had a solution. It would only work one-shot and had to be tailored for the number of sheets processed in 1 batch of 1 shot developer. But, we had something that worked and gave us usable results from otherwise useless paper.

If anyone is interested, here it is:

Dissolve PMT (Available as a solution from the Formulary and from Sigma Aldrich - full chemical name on request in this thread). Add 1 mg - 10 mg / of PMT per liter of developer. Determine that level that works for you. Use developer as a one-shot as the PMT is used up with the first and only use. So, if you do 1 sheet in 100 ml and it needs 1 mg/L of PMT, then 2 sheets would probably need 2 mg/L in the same quantity of developer and etc. This method is NOT guaranteed to work because the emulsions have changed drastically over the years, BUT, if it does, this can make the "digital" paper usable as if it were the old paper. It works simply because the PMT acts on the top (cyan) layer to lower fog and sharpnen the toe.

There is also a fix for a pink (magenta) toe, but I see no complaints of that here.

PE

Photo Engineer · Mar 30, 2011

Greg;

I will as soon as I can find it. I always think of it as PMT or Phenyl Mercapto Tetrazole, but the IUPAC name is about 3/4 of a mille long. I can never remember it. I have to look it up every time.

PE

Photo Engineer · Mar 30, 2011

Greg;

It is listed as PMT in the "old" catalog, but is not in the new one. Ask Sherry by phone or e-mail. I know they have it as I made a batch there. They have both solution and powder on the shelf.

PE

"Optimized for digital" color papers...only legend?

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