What can you say about dMax that has not already been said?  A little. And tons.

In the analogue days of old it was drilled into us by our teachers that a darkroom print required a strong black and a white. Yet, they never literally meant that. They attempted to get us to see contrast in order to awaken our senses. We needed a strong white and a strong black in order to first see that. Then, those same areas in the print became less desirable as we consciously began to see and to express light. Fine printing became more about the vast possibility of grays. It is often easy to forget how difficult it is to finely tune a print, and how easy it is to make contrast.

Carole Seborovski, Three Black Bars, 1986. Aquatint gravure from charcoal drawn tissue plates. Printed and Published by Cone Editions.

dMax really changed for me back in the 1980’s when I was printing aquatint photogravure  for painters and photographers. Etching black ink has a way of forever transforming dMax into something more substantive than absolute black. I had many different black pigments in my studio back then. Each had its own quality. Some were often too dark.

I believe dMax can be characterized in two ways. 1) It is the darkest black that is possible to produce given a specific technique/materials. 2) It is the darkest black that one chooses to generate given a specific technique/materials. These two can be mutually exclusive, and the latter does not necessarily conclude that it is less dark than the former.

dMax perhaps, should be just black enough to support the content. Like torqueing a bolt with a wrench until the threads strip, and then backing off a half-turn. That’s the target for me.

Sometimes, I do pay more attention to producing a definite black. But, I don’t do so at the expense of the near blacks. I have a technique I use that I have mentioned before that allows me to draw dMax out of the deepest darks while preserving the detail of near black. It’s especially useful when no black actually exists in the image file.

Piezography can only print dMax when a pixel value is at LØ, or RGB 0,0,0, or 100%K.

L1 prints lighter. L2, just lighter than L1. That’s one of the greatest features of Piezography: how deliberate one must be in order to print absolute black. Piezography is unique in being able to produce such a wide tonal latitude and to define it with such a huge amount of both highlight and shadow detail.

That simply is not something that Minor White, nor Ansel Adams, nor even my teacher Arnold Gassan could have achieved in silver. I mean no disrespect to these Masters. I just comment on silver’s reluctance to render detail at the toe and shoulder. This is precisely the areas in which Piezography uniquely out prints any other system.

And while silver quickly forms black, Piezography easily differentiates right up to the point of sliding into dMax. So, when I print Piezography I am reluctant to force detail to black that would otherwise print with beautiful differentiation. Then I am reminded by one who I used to print for that told me “nothing really interesting happens in the shadows, so just let it all go black!” And in Piezography if you want black, you just need to make sure that you have a lot of LØ pixels.

Cathy Cone, White Line, 2012. Piezography Warm Neutral on Canson Rag Photographique. Printed at Cone Editions.

I think about dMax in Piezography as a black that is supporting content. I don’t actually have to have a dMax and a specular. Sometimes (even often), a strong black detracts from the beauty of the grays. In White Line by Cathy Cone, the print was made without a true black. In this example, strong black would have destroyed the light that was difficult to originally capture. The darkest areas of the image are in the high L40’s. While some people might consider the image to be lacking dMax, its dMax was very deliberately chosen and defined as only a very dark gray.

For me, dMax is optional rather than requisite. Many of my own landscapes simply do not have a white point and a black point. Seldom in nature do I shoot on such bright and contrasty days that this is imposed on me. And mostly, I love shadow detail that goes on forever.


“I wanna see it painted black, painted black
Black as night, black as coal”

Mick Jagger and Keith Richards, 1966

Black itself is a context. I really like printing on a handmade paper of 50/50 kozo and cotton. It is highly absorbent and it doesn’t have an inkjet pre-coating like nearly all inkjet papers. By pre-heating this paper and printing with a very unique combination of inks, I am able to hit a dMax of 1.40. And it “feels” hugely black in relation to the print.

Standard Piezography matte printing can reach into the high 1.60‘s on some papers like JonCone Studio Type 2, Hahnemuhle Photo Rag, and Canson Rag Photographique. And some printmakers use a special but now rare and discontinued black ink (Piezography Portfolio Black) to hit the 1.80‘s on these papers.

Piezography Glossy can easily reach into the 2.80‘s on many different papers. When I make Piezography translits for customers, I hit 3.00 nervana! So, dMax is attainable.

But, keep in mind with Piezography that dMax is measured at absolute black – and absolute black is measured only by pixel values LØ (or RGB 0,0,0). While your display image may seem black, it may only be an illusion from too bright a display. Too bright equals too black. But, it is quite easy to determine if you actually have a strong black in your image using either the Histogram or the Levels tool in Photoshop.

When you open the Histogram window or palette in Photoshop it gives you a direct analysis of the pixels in your image in its current state.

In the example above I have placed the Photoshop Histogram on top of a slightly over-exposed digital capture from my Canon 5D MKII. I have positioned the mouse/cursor over the Level Ø value and it returns that I have a “Count” of 4,092 pure black pixels (Level Ø), which out of 21,026,304 Pixels is a mere 0.02% Percentile. Just doing the math, there simply is not enough pure black to make a visual reference in the print as dMax or maximum black. And as you may have gathered, I am totally fine with this because that is the dMax and it is subtle. This is how I shoot. I can repair the sky where it is overblown (notice the huge jump in pixels at the far left Level 255). Yet, the image “looks” like it has a lot of black in the tree trunks on the left hand side.

They aren’t black at all. The image is being Soft Proofed with an ICC profile for Carbon Glossy inks on JonCone Studio Type 5. The trees are actually in the L27 range…nicely very dark gray. If I wanted to print a lot of black, which I don’t, I may be disappointed. Luckily, I’m a fan of dark grays and near blacks.

Another way of looking for dMax, and one which is more visually intuitive, is to look at the image black levels using the black point Input slider of the Levels tool. When Levels is opened as in the illustration below, the same histogram is presented in the Levels Window.

If you press the alt or option key while clicking the mouse on the Levels black point Input slider, the display image will show white except for those pixels that are at or below the Input level selected. In this case in the illustration below, an Input Level of 0 reveals that the 4,092 pure black pixels are incredibly hard to notice.

In fact, I need to click and drag the black point Input slider while simultaneously pressing the alt or option key to nearly the Level 22 point before I actually notice a sizeable amount of pixels. This Level 22 area however represents 94.5% gray. You can see this in the illustration below.

So, my choices here? Live with endless gorgeous ever darkening grays, or compress everything from 94.5% to 100% together in order to form a larger mass of pure 100% black. I can do so if I choose with or without regards to the other grays near 94.5%. Or, I could just leave gorgeous near blacks be. I think by now, the reader can foretell my choice. Though, I may be tempted to finesse something in between these two choices with my technique.


Mapping dMax to dMax, or how my display dismays


So then…what about the relationship of the density range in a digital image between dMin and Dmax – and the print? That’s a loaded question. It’s loaded because the print is a definite. The image file is a definite. The display however, can be all over the place. Therefore the relationship between dMin/dMax of the display image to print can easily be askew.

For those who use hardware calibration like the Eizo CG series it is easy to get very, very close as long as they are willing to calibrate to print. But, for those using ordinary LCD/LED displays via software calibration through the video board (e.g. datacolor, x-rite), it can be hugely challenging. Calibration has been well-covered on this blog and not much has changed since.

The short of it is that the contrast of a print cannot be dialed up because there is no luminance level adjustment knob on a print to make the paper brighter and the ink darker. Using non-calibrated displays and staring at images through a blast of light makes it difficult to judge dMax when dark grays appear black on the display. The resultant print therefore “seems” to be lacking in dMax. But, it isn’t. The image file is lacking in dMax, but the display or the way it is calibrated does not reveal this to the viewer.

While a CG model Eizo can be adjusted to match the contrast ratio of a print, many other LCD/LED displays cannot. Buying a software calibration system from x-rite or datacolor necessarily decreases the fidelity of the computer’s video board which these software use to “calibrate” ordinary displays. While the instrument is placed on the display, the software actually changes and limits the video board in order to make the display “calibrated”. This necessarily reduces the output from 8/24 bit on the video board. Software calibration is better than doing nothing, but it is not a substitute for a true hardware calibrator display such as the CG Eizo. So, this is the rock and hard place.

It is really not advised to put tons of imaging work into files on uncalibrated systems, especially if the output is not matching. You really should only be editing images on systems which have displays matched to the output.

By example, we image at Cone Editions on hardware calibrated 10bit Eizo displays that are as bright as our viewing booths which are located just adjacent to the displays. The viewing booths have dimmers and 5000k light sources. Our displays are calibrated to 5000k, Gamma 2.2 with a luminance about 88. We choose 5000k because this is the light source which humans see as achromatic (neither redder, nor bluer, nor greener). 5000k is the white point (or white color temperature) which the standard human observer sees as “neutral” and can best judge color differences with. We choose Gamma 2.2 because this is the contrast at which Piezography prints. The room is very dark – mostly illuminated by the light of the display and the dimmed viewing booth. We know not to wear bright colored clothing, lest we see it reflecting off the display and “coloring” our judgement. This may sound extreme, but it is actually the standard viewing condition in nearly all professional print environments. Prints that we put in our viewing booth look uncannily like the images displayed on the Eizo when we view them through a SoftProof ICC. 100% accurate? No. We’re satisfied in getting within 95-97% accuracy.

Not to rewrite a calibration article, but a display needs to be calibrated to print. The average LCD has a luminance level over 200. The average luminance level of a correctly calibrated display (for print) is under 90. Once a display is calibrated to about the same contrast ratio of ink on paper, it can be used to judge contrast, tonality, dMin and dMax. To perfect it, a SoftProof ICC can be used to preview the image in Photoshop (and someday in Lightroom). The SoftView ICC is created using the QTR CreateICC and a spectro such as the X-Rite i1. The ICC records not only the current linearization of tone in the Piezography print, but also the paper color and how it effects the highlight shades, and it also reduces the black on the display to look like the dMax on the paper. When the ICC is selected in Photohop’s View/Proof Setup, the grayscale images turns into the color of the Piezography ink complete with highlights and dMax correct to the printed results.

SoftProofs take some getting used to. Truly, calibrated displays take some getting used to. If you think about it…when you image on an uncalibrated display you are imaging with a contrast ratio that may be as high as 800:1. Bright and sexy! When you print on matte paper you may see a contrast ratio of 250:1 in the print. On glossy this may increase to 400-450:1. Human visual systems can not possibly map dMin/dMax from uncalibrated displays to their equivalents in ink and paper. Incidentally, the SoftProof accuracy is limited by the quality of the calibration of the display. A SoftProof on an Eizo CG will be substantially more accurate than a Spyder calibration on a Mac LCD.

I tend to buy the best display, rather than the most expensive imaging station.


Just wanted to mention…


Minor White, Haags Alley, Rochester

What if years ago, an image that was captured on silver film could have been transposed onto a projector of sorts where endless tweaking and turning of knobs could have transformed the latent image into anything in real time prior to committing it to silver paper…would that actually have been appealing to Minor White?

It is so easy to rationalize that White would have used these tools were they available, or would have embraced digital were it available. But, they weren’t. And we don’t know if we would have accepted or rejected them when film was still available. Contemplative photography was not a bi-product of digital imaging.

Light reflecting off ink and transmitting through a display are so vastly different from each other. They even require different parts of our brain to visualize.

For 200 years right up until the 1990s, the Print was so dominant in the life of nearly every photographer. Today it seems more like Adobe has become the dominant factor in Photography. I still believe that fine prints come from fine printmaking, and that printing should not be an “output” activity. I’m so old school that it’s embarrassing.

I know that most Photoshop masters teach Photoshop mastery and that it is very difficult for photographers to learn digital printmaking when all their best efforts never seem to match the output. Photoshop is actually a virtual space (no matter who told you what to the contrary). The output if printed correctly, is actually the reality. I do not know how Adobe gained such dominance over printing. It wasn’t always that way, I can assure you.

One way to gain mastery over the printer is to revert to a little old school digital.

Ask yourself if you know the L values in your digital images. There are 256 of them. Only LØ produces dMax in Piezography. Only L255 produces dMin (paper white) in Piezography. You should know the range of LØ-L31 like the back of your hand. You should also know the range of L240-L255. These are the Photoshop struggle zones. This is where you adjust your shadow and highlight details. You should know what these values look like in print. You should know your gray values both in the image and in ink. You can start by printing the 21 and 51 step gray charts from QTR or go straight to 256.

As photographers we think, we see, we even speak in terms of gray value. There should not be guessing nor estimating what Photoshop L value produces what gray, what near black, or what near white. Printing always comes down to finite ink possibilities. Piezography is a very well designed and consistent system because of the K7 curves and über-steady QTR driver. Printing out test charts of grays is in my opinion, still critical as a first step until you know them like you knew your silver negs and silver prints. dMax is just the first gray on the chart.

What are your favorite printed grays? Where do you see gray giving over to dMax? Maybe you need to print only the grays from L15 to LØ. Can you identify these same values in your digital image? Have you set your eye dropper tool for 3×3 matrix? Is your Info palette set to Grayscale and RGB so you can see both % and L? Never close it. Unlike your display, it will never mislead you.

I know that dMax is desirable, but L2 and L3 are to die for! Are you willing to sacrifice gorgeous near blacks because because you are supposed to have a strong black in order to have a “good” print? This I believe, is what Minor White would have wanted to explore. These are ranges of near black and near white that silver fiber paper has never been able to resolve. These are the extra Zones – and there are tons of them. You should protect them. Don’t let staring into the light of a display convince you they’re unneeded or might look better darker. Let the print be your guide in that.

Do I know what I am proposing? you ask….  In fact, I do. I’m asking you to make a proof before you begin editing. I’m asking you to mark it up as to how you want it to be…and I realize that means contemplating it. Then, I am asking you to consult your printed gray charts to give you an idea of your target values and make these adjustments in Photoshop with respect to the values in the Info window using your Eyedropper (although the cursor of any tool is an eyedropper). Then make another proof and contemplate. Glory be! I just gave you your darkroom back. And it will make you a more skilled imager (for print). Truly it will. At some point, you’ll even understand your display better.

I’m a tough one to ask about dMax because I seldom chase it. Yet my whole printmaking experience evolves around it.