What Is This Duotone You Speak Of?

Center spread from a fund raising brochure I produced in 1992 for St. Mary of the Plains hospital in Lubbock, Texas. The duotone printing, done at a firm in western Massachusetts, was executed the old fashioned way—with process camera negatives made from my silver prints by an elderly craftsman who spoke with a Scots accent. He looked at the prints, very carefully, and slowly, having decided how he wanted to interpret my work for the press, said, “You’ll nae be wantin' any black printer in the shadow tones, then?”

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Written by Carl Weese

In my recent book review post, I touched on the topic of different offset litho reproduction processes. The most common today is CMYK, which produces “full color” printing. Monochrome photographs can be printed in CMYK, but it’s not ideal. Multiple plate offset printing with black and gray “spot color” inks is a better way to get really good monochrome photographic reproductions that are also smoothly consistent form after form, and so page after page in the publication.

An offset press halftone plate when printed can only distinguish 50–70 levels of tone. (The wide variation depends on the type of paper, the press, the care taken, etc.) Even 70 levels severely limits print quality. Almost as soon as offset lithography was developed, people figured out that they could make a vastly better monochrome print (neutral, warm, cool, livid green, bright magenta, anything you want) by using multiple plates with different inks. Two, three, four—as many as you can afford. Separation negatives were shot so that in a tritone, for example, one recorded primarily highlight values, another mid-tones, another the dark values. Using one black and two gray inks, (counterintuitively, the black ink is best used for the highlight printer, as I learned from the Scotsman) the result, this not being an ideal world, isn’t 210 levels of tone, but it’s a whole lot more than 70. A really well executed page can rival the original silver print.

Process cameras are about as common as dodos today. So, Adobe Photoshop has a duotone function, which includes the ability to make tri and quad tones, from digital files that have been captured, or scanned from film or prints. You can specify any Pantone ink formula for each separation, and you can adjust the curve for each. These controls are the digital equivalent of what a skilled tradesman used to do with the process camera. The file (incorporated into the page layout document) is then output as two, three, or four ultra-high resolution imagesetter negatives at the print firm, then plates for the press are burned from the separations. The plates are mounted on a multi-station press with the specified inks in the correct fountains, or the plates and inks can be used in sequence for multiple runs through a single station press in registration. If all goes well, the result is a publication with beautiful reproduction.

There’s a completely different way to use the duotone dialog. You can use it essentially as a Photoshop filter, best done in a duplicate layer, to manipulate the tint and tone of a file that you will send to a photo quality inkjet printer. The result, however, just to get picky about it, isn’t a duotone—it’s not made with differently inked multiple plates on a printing press. It’s a composite RGB print. Photoshop and the print driver interpret the file data into RGB, because that’s the only language the inkjet printer can understand.

Recently I’ve been studying and experimenting with the Photoshop duotone function because I plan to use it for the plates in an upcoming book project, and I plan to do the tritones myself. It’s a powerful dialog and can create interesting monochrome effects. However, despite the time I’ve spent learning to work with it, I don’t plan to use it on files destined for my inkjet printers. I can get the results I want easier-faster-better with Epson’s Advanced Black & White print driver module for my 3880, or with Photoshop color management and custom ICC profiles for my HP Z3200.

If  you try the Photoshop duotone tool and there’s something you love about the interface and you find it helps you reach the results you want, then by all means go ahead and use it for files intended for inkjet printing. These choices are all subjective. Me, I’m only planning to use it on work destined for a Heidelberg.

Carl

Carl Weese is a photographer, writer, and workshop teacher, based in Connecticut. There are many online galleries of his pictures at his website, and he publishes a daily picture blog.

©2015 by Carl Weese, all rights reserved

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Comments

[Geoff Wittig]

While it's merely producing a facsimile of actual duotone/tritone printing through my inkjet's driver, I still really like Photoshop's duotone feature for exploring digital toning of black & white prints.

As many folks know, a 'plain' black & white inkjet print using black ink and several strengths of grey may be fairly neutral, but it can also be a bit...dull. Using the full range of color inks permits a livelier print, but also opens the door for all kinds of metameric weirdness, with very different tones under different ambient lights. Inkjet printers have gotten much better in this respect since the truly ghastly Epson 2000p (I still keep some old prints around just to remember how spectacular the color shift is), but it's still an issue.

Using Photoshop duotones, you can intentionally tone (say) the highlights, shadows and midtones to taste, creating a more interesting and subtle color balance than the straight BW print can give you. Cool shadows and warm highlights, or neutral shadows and cool highlights...whatever you like. I tend to like the subtle cool/purple tonality to 3/4 tones with more neutral highlights that traditional selenium-toned darkroom silver gelatin prints can provide, but occasionally it's a hoot to go all 'Prussian blue' and print a faux-cyanotype. Great fun.

[Crabby Umbo]

Boy am I old...I mentioned duo, tri, and quad tone printing to one of the 'kids' the other day, and they looked at me like I was speaking from space...guess I better not mention stochastic printing either!

[Ken Tanaka]

Thank you for an excellent concise explanation of the duotone printing process, Carl. Those images look lovely on my iPad! (Babies are always good subject choices for health care fund-raisers!). So much care and skill went into reproducing that main image for the brochure...and then a designer mutilates it by dropping it on the gutter. I would have been really angry and made my upset well known. Did it bug you?

[John Sarsgard]

Can't possibly enumerate everything I have learned from Carl. Probably because I have forgotten some of it…hey, I'm 69 but still kicking. Carl said just enough that I will now have to play with the duotone function in Photoshop.

[Eolake]

Interesting, thanks.
So, without any black ink in the shadows, how is max black achieved?

[Edd Fuller]

Back in the 1960s, my first job in the printing trade was in a small job shop. We had little call for things like duo-tones back then, but the pressman, an old style Southerner, took it upon himself to explain to me the process of creating "Dewey" tones. It was only after I came across the term "duo-tone" in print that I got the name straight, but even to this day I think of the process as Dewey Tones.

[Bill Poole]

Very clear explanation, Carl. Thanks so much.

I believe this is a second TOP tip of the hat to Epson's printer engine in recent weeks. As someone who prints mostly monochrome using stock profiles on a 3880, I'm going to give the advanced black and white another look.

But does this give you as good an onscreen preview as you get when using duotones in Photoshop -- or the Split Toning sliders in Lightrrom--and then printing with a good profile?

[MikeR]

Carl,

I've been learning a lot lately. I went to a gallery talk by George Tice earlier this week. He prints his own silver, but has his platinum prints done in Belgium. He explained the process of three separate negatives, pin-registered. Oh! Same as dye transfer, kinda sorta. And maybe that's how layers started in Photoshop? Anyway, thank you for this explanation, and the technical addenda to your book review post, (which I just bought through the link).

[P Krzeminski]

Thanks Carl,

I produced a version of a duotone several years ago by following Richards Lynch's instructions in his book "The Hidden Power Of Photoshop Elements 4". I printed it on my HP 3210 and ended up with a pretty nice little photo. Not sure if I can send along the three images for the duotone, but here goes.
Looking forward to your book. Phil K

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[Peter Marquis-Kyle]

Thanks Carl for that useful (and nostalgic) reminder. And, in the realm of inkjet printing, let's not forget the use of RIPs and multiple-grey or low-gamut insets, which allow better control of colour tint (and better longevity) than conventional colour inksets. I'm a fan of Roy Harrington's QuadtoneRIP.

[marcin wuu]

One of the things you might want to pay close attention to is setting proper raster for both transparencies. Ideal situation would be sitting right there when the transparencies are made and seeing for yourself how the raster overlaps. This can make a HUGE difference of the final print.

[David Dyer-Bennet]

In my early inkjet printer days (pre-pigment inks; I was using HP dye printers at that point, before going to third-party pigment inks in an Epson 1200 and then falling into the Epson fold when their own dye inks came out) I used duotone and tritone to get much better B&W prints than those printers were otherwise capable of (only one black ink). It seems to be a concept with some legs.

[phil]

Curves are more flexible and not device-specific. I have a duotone preset in Lightroom that adds a tiny amount of red to the darkest tones of my black and white prints. I use it to counteract a slight blue tint that I notice in my black ink (or ink/paper combo I suppose). I don’t think that could be changed with profiling, since It’s an inherent characteristic of the printer. I’d be changing the calibration to achieve an effect, which isn’t good practice. I have a tritone that does a pretty good job simulating old Agfa Portriga tones. I don’t have an Epson so that might be able to be done with the black and white mode, but I can make a file that would print on any printer with a curve.

[ctein]

Dear Carl,

As it happens, I wrote up an introductory tutorial on using the duotone function in Photoshop for the first edition of Digital Restoration. It was cut from the second edition, so I excerpted it and put it online at http://photo-repair.com/Duotone_&_Photokit_Toning_%28from_Digital_Restoration_1st-ed%29.pdf

Epson’s Advanced Black & White print driver function works exceptionally well, and it's very easy use, but it has one big disadvantage. It leaves your final results utterly dependent upon your hardware and software configuration. If you switch to a non-Epson printer that doesn't have a similar function, or a future Epson printer/driver implements the function differently, or the function simply breaks for unknown reasons on a new machine or under a new OS (that happened on one of my systems), you're stuck. You have to go in and re-tweak the file to produce prints on your new setup that look like your original ones. If you didn't happen to file away good reference prints, you'll be relying entirely on memory.

The nice thing about using something like the duotone function is that it's built into the file. You'll always get that toning no matter how your setup changes or what printer you use (well, subject to the detail that no two printers print exactly alike). If someone wants to make it truly software independent, flatten the final PSD, save it as a TIFF, and you can print it anywhere you want.

Don't get me wrong. I really like the results that Epson’s Advanced Black & White function produces. I just can't trust it to be there for me in the future.

pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
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-- Ctein's Online Gallery http://ctein.com
-- Digital Restorations http://photo-repair.com
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[Carl]

Grab bag of answers:

Ken, the only thing better than a baby picture for a healthcare fundraiser is a bigger picture of a baby. Truth be told, I was the art director as well as photographer, and the five-column big print on one spread was a consistent design element of the series of brochures I did for this fundraising firm. Since I knew it was coming, in any situation that I thought might yield 'the big one,' I framed in a way that would take advantage of the large print size and at the same time minimize the distraction of the gutter. I did talk the client out of wanting The Big One to be a full double-truck bleed with the gutter running right up the center.

Crabby, my sources tell me that stochastic screening is alive and well. Not only that, and relevant here, it seems that if CMYK is a requirement for design or logistical reasons, but monochrome reproductions are needed, stochastic screening is the way to go.

Geoff, exactly. If the duotone dialog appeals to you and produces effects you want for inkjet printing, go for it.

Eolake, I don't know what magic formulas the old Scotsman used to expose and develop his process camera negatives. Experimenting with PS duotones/tritones (only making composite RGB test prints so far, no press tests yet) I find it works well to have the black printer reach through the whole scale, but favoring the highlights in its curve. Having *some* of all three inks at the deep end seems well able to deliver a convincing black.

Edd, Dewey Tones sounds much better!

Bill, I use very little color toning for monochrome prints. I stay quite neutral. The Epson ABW gives tone that's faithful to what I have on screen and seems to give a "cleaner" print than I get in mono using PS management and profiles with this printer. But if you are using strong color shifts that you want to preview on screen, you're better off the way you are doing it now. If I feed a neutral RGB file to the Z3200, it uses only its four K inks. They are not purely neutral, they obviously were carefully designed to deliver a superb monochrome print, while also supporting the more usual full color function demanded of the printer. If I can make a tritone profile that replicates what my Z3200 produces...

MikeR, using multiple sensitizer coatings and registered exposures is an unusual but established Pt/Pd technique, though I've never felt the need to try it. Another sort-of-duotone printmaking technique is to print a weak platinum image (strikes me as nuts) or a weak cyanotype image (much more $ensible) and follow it with multiple registered printings in gum bichromate. In gum printing, each of the multiple printers emphasizes one section of the tonal curve exactly because a single gum layer has an even more limited ability to distinguish tone levels than an offset litho plate. I've seen some cyanogumotypes that were lovely.

[ctein]

A P.S. to my earlier post.

The downside to Duotone mode is that it only works on 8-bit files. If your original photograph was created in 16-bit mode, you'll want to do a "save as" on the duotone conversion, or you'll be throwing away a lot of tonal information you might need in the future.

[Carl]

Ctein, interesting point. Now I want to try a comparison between the 3880 and Z3200. They have vastly different approaches. With a neutral rgb file, the HP uses only its four K inks, no balanced amounts of LM and LC like Epson. For color files (or strongly toned mono) it uses a lot of undercolor replacement to control metamorism. When I first got it, I was surprised that a warm monochrome file made with the PixelGenius Toolkit went nearly neutral when sent to the HP even though it was fully color managed with custom ICC profile. Weird parallel, nearly the same thing happened if I sent a file like that to an Epson 4800 in Adobe RGB instead of ProPhoto RGB. The PG tools reflected their creators strong preference for ProPhoto for inkjet files. I'll set up a couple strongly tinted duotone files and see how the printers handle them.

[Jeff Glass]

Awesome post. This is why I come here. I may never use the wealth of information here, but I may.