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A Striking Achromatic Wall Banner

Today as my fiancee and I were driving away from our favorite new thrift store we saw a multi-panel, large-format graphic of a number of elephants. It was on the exterior wall of a 7-Eleven convenience store, and it was dynamic for a number of reasons.

First of all, to give this some context, the overall printed banner comprised five or six distinct vinyl panels about three feet wide and six feet high that abutted to one another. The color scheme was achromatic: that is, no color, just white, black, and one or two intermediate grays. (I’m relying on memory here; hence, the sketchy details.)

That said, it was a nuanced rendering of elephants in the jungle that worked well because of its simplicity and its limited color palette. Many graphic designers would have made the job a 4-color process work; however, this designer chose a more subtle approach that complemented the style and exterior of the 7-Eleven store.

Moreover, I recognized a technique used by the old masters, the painters and draftsmen of the Renaissance and thereafter. The overall background of the five- or six-panel wall hanging was an intermediate gray. There was even a mostly blank gray panel on either side of the group of elephants, allowing the viewer to rest her or his eyes. Black ink applied sparingly created the shadows within the large-format graphic, and highlights of pure white made the lightest areas pop out.

This is exactly the approach the famous paintings and drawings of the classical art periods reflect, with a middle tone for the background (often a brown or sepia), a dark pigment for the shadows, and perhaps white for the highlights. The same structure was evident in the pencil drawings of the period as well as the drawings made with clay Conte crayons (in white, black, and sanguine, which is a reddish-brown hue).

Back then it worked well, creating a distinctive and dimensional look. And right here in a multi-panel, large-format print banner, probably produced on large-format inkjet equipment, the very same artistic treatment, modified slightly for advertising art, worked just as well, created an image unified in design and color, and complemented the exterior appearance of this particular 7-Eleven convenience store.

Too much color (the norm today) would have been an overstatement. An achromatic rendering was just right.

An Addition to the Large-Format Banner

In fairness, I want to admit that I wrote the aforementioned a while ago. Interestingly enough, a week later when my fiancee and I returned to our new thrift store, we saw a revised (or augmented) version of this same wall hanging. A week later, the large-format banner designers had added paint over the inkjet wall hanging, rendering it in full color and making it no different from all the other banners we see.

What a shame.

But you can still learn from the old masters about such things as a limited palette (in this case initially just black and white, but you may want to choose a few brown tones of various levels of lightness and darkness). And you can be mindful of the various shades between the lightest and darkest. Don’t choose too many (the initial wall hanging of the elephant had only black, white, and maybe two grays). And even though this elephant wall hanging was an inkjet enhanced by painting (presumably in acrylics), all of these design principles can be directly applied to everything from a poster to an invitation to the cover of a print book.

Black-and-Gray Duotones

One of the books my fiancee and I found at our favorite thrift store came from the National Gallery of Art in Washington, DC. Entitled The Americans (Photographs by Robert Frank), this collection provides a window into the years 1955 and 1956 in America. It is a surprising portrait in its intimacy, including everything from pictures of people at rodeos to people on buses to people in elevators. The people’s faces reflect all manner of emotions. When you page through the book, it is as though you are an observer in their rooms witnessing their most personal, private moments.

This is the perfect opportunity to use one of the techniques of offset lithography to enhance this 10" x 8" (oblong) case-bound book with a technique called the black-and-gray duotone.

First of all there are a number of ways to render photographic imagery, including black and white (actually black-only photos) and 4-color images, which are known as full color because they capture most of the color spectrum.

In all cases, since offset lithography only allows you to reproduce black or white with no intermediate grays, you need to build these tones with halftone dots of different sizes. These halftone dots, arranged in rows on a grid (with more or fewer dots per inch depending on the frequency of the line screen) are either larger or smaller. Larger halftone dots carry more ink; smaller dots carry less ink.

When you break a full-color image down into the process inks (cyan, magenta, yellow, and black) and print halftone screens of each of these colors (on top of each other and at slight angles to one another), you can reproduce most colors. However, since the color gamut (the number of distinct colors you can reproduce) is still somewhat limited by only using cyan, magenta, yellow, and black, some printers with multiple-unit offset presses will add match colors (PMS colors) to augment the color spectrum or gamut.

However, it can get expensive when you start adding colors to the CMYK color set.

It is also possible to print black-only halftones. These also have dot patterns (a regular grid of halftone dots), unless you’re using stochastic screening, which looks more like inkjet printing work. These comprise more minuscule dots to create more color and fewer minuscule dots to create less color.

The problem with halftone dots is that they can only represent a limited range of tones (from the lightest light to the darkest dark) while still maintaining a crisp distinction between one tone (let’s say a 10 percent highlight) and the next darker tone. When I say limited, I mean that nature can produce much lighter lights and much darker darks (and more steps in between) than you can reproduce via offset lithography.

That said, you can add to the range by adding colors. For instance, you can create a four-color quadtone using cyan, magenta, yellow, and black inks to reproduce a black-and-white continuous tone photo (i.e., the original image). And with the proper desaturation of color (removing the color green, for example, and focusing on various tones closer to black and gray), you can create an offset printed image that looks black and white but (if you look at the printed image with a loupe) actually contains cyan, magenta, yellow, and black halftone dots tilted at specific angles (called "irrational angles") to one another.

The combinations of colors work individually and together to reproduce maximum image detail, maximum tonal range from darkest to lightest tone, and maximum differentiation between adjacent tones (10 percent gray vs. 20 percent gray, for instance). All three of these variables make for a depth and richness in the photos that you could not otherwise achieve with offset lithography. In the middle, between 4-color black-and-white images and black-only images is the duotone (usually black plus one other color). Black and gray duotones are identifiable with a loupe by the halftone dots of these two colors. Through the loupe you will see either black dots or gray dots (and no other colors), although these halftone dots will be any number of sizes on a regular halftone grid.

As with the 4-color black and white, the duotone can enhance both detail and tonal range. Unfortunately, you can’t produce an accurate proof of a duotone using cyan, magenta, yellow, and black inks (i.e., using inkjet inks from an inkjet proofing device). You can only create an accurate duotone result with an on-press proof (real offset inks used to print a proof on a small offset press). Therefore, it’s smart to use pre-made tone curves (Photoshop settings) suggested by your printer to match previously printed samples of duotones (i.e., to ensure success).

That said, as the book my fiancee found, The Americans (Photographs by Robert Frank), distinctly shows, a well-executed duotone using either black and a color or black and one gray (a premixed, PMS match gray, not a tone or screen of gray), you can achieve results that add significantly to the emotional power of a photo.

This is an especially useful artistic device that is based on an offset lithographic printing technique. If it interests you, ask your printer for sample books showing the options for two-color (black-and-green, for instance) duotones, black-plus-gray duotones, and 4-color black-and-white quadtones.

[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]