Back in Black (and White) Milwaukee WI

When was the last time you saw a truly neutral black and white photograph produced on an inkjet printer? If your answer is never, read on. What makes this so difficult to achieve? With the precision of photo editing software, monitor calibration tools, ICC color profiles and new ink technology, you would think you could just set your printer or file to black and white and produce a black and white print to rival the best of Ansel Adams.

But that's not what happens, is it? Frequently your print has a magenta or green cast, poor black density, and a lack of detail in the shadows and highlights. This article will unravel some of the mystery around neutrality in inkjet printing and provide some insights and some options to produce neutral black and white prints.

Let's start with why we like black and white so much. Isn't black and white old, simple and without vibrancy? Remember Gary Ross' Pleasantville where black and white represented innocence and boredom? It was color that represented vitality, excitement and risk. Yet in photos and art, the old, simple black and white image has depth and excitement well beyond the color equivalent. Maybe it's the lack of color that helps us focus on the details—the shadows and tonal ranges—more than if they were fire truck red or electric blue. That is why achieving neutral levels of gray is so important if you are working in a black and white photo medium.

History

Maybe you've been in the photo industry for years and remember the days of traditionally processing black and white images. Or you're new enough to printing that words like enlarger, fix, and stop bath mean nothing to you. Either way, the frustration in trying to achieve black and white neutrality is equally shared in digital inkjet printing.

Traditional black and white photography uses a silver-based process that requires chemistry to develop images onto paper. This usually means turning your basement or a portion of your studio into a darkroom for processing and printing. Most photographers celebrate their ability to transform a latent image on gelatin into the perfectly developed negative with the most dynamic range available. But it takes extensive testing to determine the exact amount of chemistry, time, temperature, and agitation to produce the perfect negative. Countless hours are then spent exposing, burning, dodging, masking, processing, fixing, and washing to produce the perfect print. And no two prints are ever the same.

Digital Capture

Today most images start life as a color digital capture. While there are certainly some holdouts that still prefer traditional analog photography, most of these are in the black and white world shooting 4x5", 8x10" or larger negative sizes, which will ultimately be scanned into a computer and printed digitally anyway.

So how do you convert your color digital capture into a perfectly balanced black and white image? There is an abundance of tools, filters, processes, and plug-ins that help convert your color capture into the black and white "negative" that you will send to your printer. Since black and white images do not have the distraction of color, the sharpness, detail, and tonal range are critical to produce a dramatic print. Convert your file the wrong way and you will throw away much of the data needed to create that breathtaking black and white print. Convert it the right way and you have created the "golden negative" that can produce consistent print after print.

Printing Methods

Another very popular traditional black and white process is lithographic printing. Chemistry and the repulsion of water and oil are used to create a plate that generates highly detailed images. Lithographic printing can vary the dot size up to 100 different sizes, and uses only black ink to create a perfectly neutral and near-continuous tone image. For short run, limited edition printing, this process in many respects has been replaced by inkjet printing.

Inkjet printing is not only safer as it minimizes exposure to harmful chemicals, but it is faster, less expensive per print and delivers more consistent results. Yet inkjet printing is not without its own set of challenges. Media (paper or film in this case) and ink combinations can make all the difference in the world. While the right combination can produce an extensive tonal range, maximum density, and a pleasing finish, the wrong combination can derail you before you even get started.

Printing with cyan, magenta, yellow, black, light cyan, and light magenta (CMYKcm)—or some combination of four- or six-color inks—is usually the first method used to create black and white inkjet images. Yet there are inherent issues when printing with this type of inkset. The most common issue is image color cast because you are printing with a combination of CMYK inks instead of just black. This is why calibration and profiling are the most critical steps when printing with color inks. A very accurate custom profile is necessary to create a neutral black and white print. The human eye can determine a color cast in neutral colors much sooner than in more saturated colors. That means a small color cast in a black and white image will be noticed when a larger color cast in a color image may not.

GCR (Gray Component Replacement)

Leading RIP software packages for wide-format printing include a GCR tool that can replace much of the CMY component with black. The more CMY replaced with black, the easier it is to achieve neutrality and minimize metamerism (see 'Lighting' below for more discussion on metamerism). The downside of a greater amount of GCR is the introduction of black into the lighter areas of the image, which reduces the shadow and highlight detail. The increasingly shrinking dot size from printhead technology enhancements has helped to minimize the impact of GCR on these details.

Lighting

Although we like to think of lighting in terms of light and dark, the color or temperature difference between variations of natural and man-made lighting can greatly affect the color we perceive as we look at an object. This effect is called metamerism. Metamerism is the culprit when an image appears neutral in normal room illumination (fluorescent, tungsten, daylight), then suddenly shows a red or green cast in another. A popular example of metamerism is when a sock looks brown in one type of lighting, black in another, and blue in yet a third lighting type. The type of lighting under which objects are viewed can greatly affect the interpretation of neutrality in black and white (and in the case of socks, may even cause embarrassment in public.) While metamerism is not unique to a particular media or inkset, it is a reality of how we perceive color, which makes the quest for a truly neutral black and white print even more challenging.

Printing with only K

Using only black ink is another potential solution to minimize color cast, but you may experience limited detail in the highlight areas because of the fixed number of dots. To combat this, try one of two methods. First, create very small dots and/or dots of different sizes to hide the contrast between the black dots and the white paper. Or try adding additional dots of color or diluted black to fill in the gaps between the dots of black ink. Be careful—adding too much color ink to the lighter areas can produce the color cast mentioned earlier.

Multi Black Inksets

There are specialized third party inksets that contain multiple dilutions of black ink. Replacing your current set of CMYK inks with these multi-black inks will add detail and tonal qualities not found in any previous inkjet printing method. However, you must go through a lengthy (and costly) process of switching back the inks in order to print color images. If you are committed to dedicating your printer to producing only black and white prints, this might be your best option.

When using these multi-black inksets, drivers from the printer manufacturer will not work, as the printer is expecting that the ink cartridges are filled with CMYK ink. Therefore, you will need to use a different driver or RIP that is specifically designed to maximize this inkset. These are sometimes available from ink manufacturers or from third party software developers. ONYX Graphics, Colorbyte, ErgoSoft, and BowHaus, plus shareware Quad Tone Rip, all offer the capability to either control these multi-level blacks or control the original inkset to produce a neutral black and white print.

As these multi-black inksets have gained recognition and acceptance in the industry, printer manufacturers have taken notice and integrated support for three or more levels of black inksets into their printers. Some of the newer printers released in the past two years can accommodate up to 12 different inks to enable simultaneous color plus black and white printing. With these printers there is no need to swap out the CMYK inksets for the black and white multi-black inksets offering the best of both worlds. Some of these printers also include a gloss optimizer that eliminates the bronzing effect; matte and gloss blacks; and the ability to create on-board calibrations and profiles that neutralize the color variability of the printer.

Print Media

When it comes to choosing the right media, there are many factors to consider. Printer and ink compatibility should be at the top. Beyond that is a wide choice of media types (paper, film, canvas, fine art), thicknesses, densities, base color tints, smoothnesses, and finishes. In addition there are key features that further differentiate each media. These include coating type, dry time, gas-fastness or ozone fade resistance, water resistance, and others. So which should you choose?

Media manufacturers have developed new inkjet printing substrates that are compatible with today's new inksets and combat the issues of color cast and ozone fade. These papers and films are optimized for the eight- and 12-color pigment inks that have now become the standard in the industry. These media sets are usually coated with a microporous topcoat that not only absorbs the pigment ink completely, but also helps to control the dot size and shape, and creates a waterproof and long lasting print. They are available with glossy, satin and lustre surfaces, which correlate with the most popular traditional silver halide photo papers in use today.

You will often find a wide range of paper whiteness that can vary from a creamy white (more yellow) to a bright blue-white (usually found when the paper color has been enhanced through the addition of optical brighteners). Inkjet paper manufacturers will often publish the color values of their papers using CIE 1976 (L*, a*, b*) color space values. When the b* value is zero, the blue-yellow cast of the paper is considered neutral. When there is a negative b* value, the paper is shifting to blue/white; and when b* is positive, the paper is shifting towards yellow/white. Depending on your taste, choose a paper that has a white point that suits your printing requirements, as the "white" in black and white printing will be dependent on the whiteness and tint of the paper.

Fine art inkjet papers, similar to traditional watercolor papers, and inkjet canvas are also very popular when printing black and white images. These substrates simulate the matte and textured surface of traditional fiber base photo paper and traditional canvas. Papers that include low acidity, are pH neutral or alkaline tend to be better choices when print longevity is a concern. Papers with a high acidity can turn yellow or become brittle over time. A wide range of basis weights and finishes are available in this category and you are strongly encouraged to test before you buy.

Black & White Films

For specialized applications such as screen printing, inkjet printable clear films have been developed that create print positives with a high D-max. The high black ink density combined with the very low ultraviolet opacity creates a screen master that can cleanly and quickly burn screens while still maintaining fine detail.

Final Thoughts

I hope this article has instilled a renewed excitement in black and white imaging, and that you will try converting and printing some of your color images into black and white prints to see the different viewpoint this medium can present.

Dan Halkyard is Director of Marketing for Océ Imaging Supplies. He is responsible for all wide format media including display graphics, reprographics, photographic, proofing, and CAD product lines as well as the brand management and positioning of Océ Imaging Supplies. For additional product information, visit www.oceusa.com/imagingsupplies.