Dynamic Range of photo Paper

[rconey]

Hello.

 

Any significant difference in dynamic range of various types of photo papers? What have the highest values?

 

Thanks,

 

R Coney

[conrad_hoffman]

Yes, and AFAIK it's mostly surface finish. As you move away from full glossy, you lose maximum black and the curve moves up in that region. Paper base matter a bit too. I recently posted a link to Practical Sensitometry, which seems not too useful these days, but it shows the difference between papers on page 5  

Now that said, or shown, you can make a perfectly fine print on all manner of different matte or art papers. The eye isn't very good at detecting maximum black, in fact in the old film days, an exposure time on the enlarger that gave true maximum black was usually way more than was appropriate for the print/negative. Almost every decent print never achieved maximum black. Today I'd just say, if it looks like black and the print works, it's black enough.

[paddler4]

I'd give a somewhat different answer. I agree of course that coated papers in general have larger dynamic range than uncoated papers. However, I think there are some images for which the difference is quite substantial. It's not just a matter of losing blacks on matte paper. Papers with smaller dynamic range have less contrast, less pop. Moreover, the surface influences how much fine detail is apparent.

So IMHO, it's an important choice, and the best choice depends on the image and what you want to do with it. I do a lot of photography that emphasizes small details and relies on contrast, e.g., close-up and  macro work, so I use mostly coated papers. for some other things, however, that's not a good choice.

There are also differences among papers of a type, as Conrad noted. My go-to paper for most serious printing used to be Canson Baryta Photographique. when they discontinued it and replaced it with a paper with a smoother surface that I didn't like, I ended up spending a lot of time and money printing test prints on a bunch of different papers looking for replacements. However, these differences are generally much smaller than the general difference between coated and uncoated papers.

[conrad_hoffman]

Certainly agree that you have to pick a paper that's appropriate to the subject! I just recently measured some papers so here's a couple numbers. Red River Polar Matte #1870 went from a density of 0.05 to 1.65, a difference of 1.6 and a dynamic range of 39.8:1. Red River UltraPro Gloss #1656 went from 0.07 to 1.98, a difference of 1.91. That's a dynamic range of 81.3:1, quite a bit better. In spite of the difference, the Polar Matte is one of the nicer matte papers I've tried, giving good contrast and detail. It's especially suited to locations where windows and such cause a lot of reflections. I still prefer glossy for most things.

[conrad_hoffman]

We're in the digital darkroom, but the numbers aren't much different for wet process papers. My printer is a Canon PRO-100 with dye based inks. I don't know if pigment inks can give a deeper black.

[rconey]

Thanks, all

[glen_h]

In addition to the dynamic range, there is the shape of the whole characteristic curve.

It is easy to see if the image isn't using full black or full white, but not so easy to see in between.

Otherwise, Ilfobrom Gallerie FB data sheet is:

https://www.ilfordphoto.com/amfile/file/download/file/1741/product/722/

 

It seems the maximum density is about 2.4 for glossy and 1.4 for matte.

[Ed_Ingold]

Divide the density (reflectance) range by 0.301 (the square root of 2) to calculate the dynamic range in f/stops. The curve is rather pronounced, so a good method is to measure from the intersection points of the high and low densities with the slope of the curve at its inflection point. That compensates for the heel and shoulder curvature.

The characteristic curves (log exposure vs log reflectance) can be obtained from the manufacturer's data sheets.

[rconey]

What are the largest ranges, in F-stops? I don't think about the calculations enough to do them. I recall the old slide film was about 5 stops. I think the modern cameras are 12-14 stops at capture. The challenge is then to compress that say 12 stops onto the range held by the paper.

I think.

[Glenn McCreery]

11 hours ago, Ed_Ingold said:

Divide the density (reflectance) range by 0.301 (the square root of 2) to calculate the dynamic range in f/stops. The curve is rather pronounced, so a good method is to measure from the intersection points of the high and low densities with the slope of the curve at its inflection point. That compensates for the heel and shoulder curvature.

The characteristic curves (log exposure vs log reflectance) can be obtained from the manufacturer's data sheets.

Ed - as I am sure you know, the square root of 2 is not 0.301.  Log base 10 of 2 is 0,301, which I think, is what you were trying to say?.

[Ed_Ingold]

Brain f**t

[glen_h]

On 4/27/2023 at 9:54 AM, rconey said:

What are the largest ranges, in F-stops? I don't think about the calculations enough to do them. I recall the old slide film was about 5 stops. I think the modern cameras are 12-14 stops at capture. The challenge is then to compress that say 12 stops onto the range held by the paper.

I think.

In another discussion today, I decided that Ektachrome is about 6.5 stops, but that depends on how far you go on the curve.

The reason for that, and it isn't especially obvious even when you know, is that the contrast for slide films has to be greater than one.

(The gamma is about -1.5 for Ektachrome.)

https://imaging.kodakalaris.com/sites/default/files/files/products/e4000_ektachrome_100.pdf

If it isn't, the slides look dull. 

So, it is about 2 log10 units for exposure, and -3 log10 units for density, for a slope of about -1.5.

 

And one reason some people like slides more than prints, is that you can get more dynamic range

in a projected slide than in a viewed print.

 

Cameras might capture 12 to 14 stops, but the useful part of actual scenes is much less.

They don't compress them into the range for the print, but instead select an appropriate subset.

 

If you do the math, it seems that it should never work. 

With about 5 (matte) to 8 (glossy) stops for prints, and with an appropriate print contrast,

only about 3 to 5 stops of dynamic range go in.  (As with slides, the viewed contrast

needs to be higher.)

 

But somehow we live with it.

 

The data sheet for Endura paper is here:

https://imaging.kodakalaris.com/sites/default/files/files/resources/paper-endura-techpub-e4070.pdf

the slope is about 4 over the straight region.  Multiply by about 0.5 for Portra, and the overall

slope is about 2, between exposure and print.

The density range is about 2.3, or 8 stops, but only about 4 stops in the original scene.

But you get to select at printing time, which four stops you want in the print.

(Or whoever, or whichever machine, makes the print.)

 

 

 

Edited May 2, 2023 by glen_h
fix spelling

[glen_h]

On 4/7/2023 at 11:52 AM, rconey said:

 

Any significant difference in dynamic range of various types of photo papers? What have the highest values?

 

 

Forgot to answer this one:  glossy.  But try not to get too much reflection right to your eyes.

[Alan Marcus]

@Ed_Ingold: The square root of 2 is 1.414 (1.4 will do nicely). To find the dynamic range we indeed divide the density range by 0.30. We do this because the time-honored unit of exposure is the f-stop. The increment of change of the f-stop is a doubling (2X increment). Density is measured using logarithmic notation base 10. The value (number) 2 converted to logarithmic notation base 10 is 10 elevated to 0.301 power. In other words, 1 f-stop exposure change yields a density change of 0.30 density units.  However, this requires that the plot of film have a slope angle (gamma) of 1. Most films have a gamma of 0.8. This reduces the effect of one f-stop change to 0.30 X .8 = 0.24. Photo papers have a gamma of about 2. Thus 1 f-stop change yields 0.30 X 2 = 0.60. This gamma of 2 is due to the fact that we view prints by the light of a nearby source. This light plays of the paper traverses the image on the paper, hits the white undercoat and reflects back through the image to our eye.  In other words, the viewing light makes two transits through the image to arrive at our eyes. The typical dynamic range of film is about 256 (about 8 f-stops). The dynamic range of chemical-based photo paper is about 32 (5 f-stops) for a glossy paper, less, maybe 4 f-stops for a matte paper.

[rconey]

I would not pretend to follow the math, but the results you give are in line with my expectations.

My impression that "the camera dynamic range of 12-ish stops is compressed into the paper dynamic range of 5" was questioned above. Not true? I guess the other part of the question is  what is the scientific result? What I see printing (or at least soft proofing in photoshop) is some loss of contrast in the image.

[paddler4]

On 5/18/2023 at 9:06 AM, rconey said:

I would not pretend to follow the math, but the results you give are in line with my expectations.

My impression that "the camera dynamic range of 12-ish stops is compressed into the paper dynamic range of 5" was questioned above. Not true? I guess the other part of the question is  what is the scientific result? What I see printing (or at least soft proofing in photoshop) is some loss of contrast in the image.

Yes, the DR captured by the camera is compressed to a narrower range when printing. And yes, a loss of contrast is a common phenomenon, depending on the type of paper. It's most severe with matte and fine art papers and least severe with glossy and metallic papers, to overgeneralize. I print most often on either luster or baryta papers, which don't lose too much contrast, but I often end up increasing contrast a small amount when softproofing. One has to be careful doing that because that boost will compress the tails of the distribution, and in the case of some images, you can lose shadow or highlight detail.

[NAwlins Contrarian]

Talking about inkjet photo papers, there are two ways to look at this, and a basic issue underlying the discussion.

The basic issue is that although paper white is the same regardless of the printer / inks, maximum black can vary to a substantial / visible degree depending on the printer / inks.

Now the two ways to look at it:

(1) The easy thing to do is to compare the ICC profiles for the printer + inks + driver settings + paper combinations of interest. Various tools can do this, and if the ICC profiles are the older-type v. 2 profiles instead of the newer-type v. 4 profiles, then the free ICC View website will calculate paper white (and gamut volume) and let you optically inspect maximum black (bot darkest neutral and darkest color). You might find e.g. that a particular combination has, on the L* scale from 0 to 100, a range of 90, e.g., L* min = 6 and L* max = 96. With my little Epson, the papers with the largest range (Hahnemühle Photo Rag Pearl, Mitsubishi Pictorico Pro Hi-Gloss White Film, Epson Legacy Platine, and Epson Ultra Premium Glossy) have a range of 93, although some are on the whole darker (range 3 to 96) or brighter (range 5 to 98). At the other end of the performance envelope, the the paper with the smallest range (Epson Ultra Premium Matte) has a range of 77 (19 to 97).

(2) The more traditional thing to do is measure optical density. I'll use the examples above to compare. If as stated Red River Polar Matte has a density range in some unspecified printer of 0.05 to 1.65, then right, that's a difference of 1.60 and a dynamic range of 10^1.60 = 39.8:1. To convert instead to f-stops or EV, 1.60 / log(2) = 1.60 / 0.301 = 5.3 f-stops. Likewise, if Red River UltraPro Gloss has a density range (again) in some unspecified printer of 0.07 to 1.98, then right, that's a difference of 1.91 and a dynamic range of 10^1.91 = 81.3:1:1. Again, to convert instead to f-stops or EV, 1.91 / log(2) = 1.91 / 0.301 = 6.3 f-stops. So with this unspecified printer, Red River Polar Matte has printable range of about 5.3 f-stops, and Red River UltraPro Gloss improves that by about (just a hair more than) 1 stop to about 6.3 f-stops.

FWIW, in most cases non-matte and matte papers have relatively similar paper whites, but non-matte papers can usually show substantially darker blacks.

And if there's a way to convert between L* and optical density, I don't know what it is--but I'd love to know.