A fundamental design and life lesson from the Zen arts is to never use more when less will do. This goes for the use of color as well. The problem with most slide presentations is not that visuals contain too few colors, it's that they contain too many. A common practice is to use several different vivid hues (colors) in presentation slides when even a single hue in various shades or tints would have been more effective. The ancient art of Japanese brush painting called Sumi-e (墨絵) provides a powerful lesson concerning the use of color, communication, and restraints. Sumi-e was brought to Japan from China and is an art deeply rooted in Zen, embodying many of the tenets of the Zen aesthetic including simplicity and the idea of maximum effect with minimum means. In Sumi-e, great works are achieved with only black ink on washi (rice paper) or silk scroll. Using the black ink to achieve several variations of tones, we learn that powerful visual messages can be created with a single "color" in the form of different shades and tints. (The painting on the right is by Kathleen Scott, a talented Sumi-e instructor at Kansai Gaidai University in Japan.)

In Sumi-e, much is expressed through a combination of empty space and monochromatic strokes that range from the extremely light gray to black. Yet a red seal is placed in the composition when the work is complete in such a way that it contributes to the balance of the picture. Red, of course (it's more of a reddish "flesh tone" called shuniku), would pop out in a sea of black, gray, and white empty space and draw much attention to itself. But in the Sumi-e paintings the stamp is small and stands out in a far more harmonious way that serves to anchor the flow of the composition. Sometimes the stamp is meant to be the first thing that attracts the eye; in other works it may be created to serve more as the end point. Either way the lesson is clear: few colors carefully selected and positioned can be more effective than many colors indiscriminately placed.

The value of light-dark
Nōtan (濃淡) is a Japanese concept describing the use of light and dark aspects of a design in a balanced and harmonious way. Whether you use many hues or just shades of gray in your own design work, the effective creation of light and dark elements in a design is fundamental to its clarity. Imagine, for example, a colorful painting that still maintains much of its clarity even in very low light conditions. It was the careful use of light and dark in the composition that contributes to the picture's interest and expressiveness even when the hues become nearly imperceptible. Using colors can be very effective for establishing emphasis or setting a mood, but it's the careful use of the visual's light and dark elements that will contribute most to the visual's clarity. Although the sumi (ink) is black, it is possible through technique to create many shades of gray or many "colors." This use of color and arrangement of light and dark is effective for creating depth and movement in a composition. The lesson from Sumi-e regarding color is simple: more can be achieved with less, not more. 

Expressing the essence with less
The objective of Sumi-e is not to recreate the subject to look perfectly like the original, but to capture its essence — that is, to express its essence. This is achieved not with more but with less. Therefore, useless details are omitted and every brush stroke contains meaning and purpose. The minimum amount of strokes or lines are used to convey meaning. Each brush stroke is meaningful and has a purpose. There is no dabbling or going back to make corrections. The ink is indelible and you have one chance to get it right. The strokes themselves, then, are said to serve as a good metaphor for life itself. That is, there is no moment except for this moment. You can't go back, there is only now.

Sumi-e is another example of an art that embodies the very essence of simplicity and yet is in practice complex and takes a lifetime to master. This aspect of the art of Sumi-e too is a metaphor for life: One never truly masters the art of life or achieves perfection. The pursuit of perfection is the journey, and the journey is what it's all about.

8 key lessons from Sumi-e

1. More can be expressed with less.
2. Never use more (color) when less will do.
3. Omit useless details to expose the essence.
4. Careful use of light-dark is important for creating clarity and contrast.
5. Use color with a clear purpose and informed intention.
6. Clear contrast, visual suggestion, and subtlety can exist harmoniously in one composition.
7. In all things: balance, clarity, harmony, simplicity.
8. What looks easy is hard (but worth it).
   

Applying the lessons to the common slide
Below are two different designs of the same simple bar chart. If we remove the hues by changing the slides to grayscale we can then see the luminance values and the contrast — or lack of contrast — between light and dark areas of the slide.

 
ABOVE The first "colorful" slide is not only a bit unpleasant to look at, it's not clear what part of the chart is emphasized. If we change it to grayscale, the bars for USA and UK look almost the same. For those with some form of colorblindness, it may be unclear which bar is being emphasized, if any. In such a simple chart this may not be a big problem, but for more complex charts this lack of clarity will be an issue. There is a cool website called Vischeck that can check your images or webpage to see how they might appear for people with various forms of CVD (color vision deficiency). Test your images here.

 
ABOVE The orange used in the first slide clearly emphasizes the top bar. When turned to grayscale, the difference in value still makes it clear which bar was emphasized (although the bottom three have more contrast, the top bar is clearly different). Again, with such a simple chart, it may not seem like the biggest thing in the world to get right. But it all matters. And for more complex information graphics, it is essential that we use light and dark effectively.

As color expert Maureen Stone has said: "Get it right in black and white." That is, pay attention to the luminance or value in a graphic, not just the hues (colors). "Remember," says Maureen  "most ideas can be well-presented in black and white. Add color carefully and for a purpose, and your results will be both beautiful and functional." I highly recommend Maureen's wonderfully detailed book called A Field Guide to Digital Color. This is the definitive book on digital color.

Links
• Checkout Master Sumi-e artist and jazz musician Drue Kataoka's website and blog. Impressive person. I always love jazz musicians who see the connection between Zen and jazz (or the other way around).
• Go here on Google to see myriad videos on how to do Sumi-e.