Graphics Reference
In-Depth Information
Figure 16-10:
On a black background, this ship traffic map uses a
luminance spectrum because brightness naturally demands attention,
whereas on white, red stands out most.
Another principle closely related to optical properties making colors more
noticeable is that different backgrounds (light or dark) perform better or
worse in different mediums. White backgrounds are a better choice for
paper, where pigments are applied for foreground elements. Dark
backgroundstendtoperformalittlebetteroncomputerscreens,wherelight
is invoked for foreground elements.
However, this is highly dependent on the quality of the display device.
Dark backgrounds tend to perform poorly on a digital projector because the
maximum luminance is so much lower that it becomes difficult to see small
or thin objects below a certain level of brightness. There simply isn't enough
strength in the light being pushed through such a small window. White
backgrounds have a different issue with projectors in that the amount of
bright white tends to wash out color depth, but the result is not a total loss.
Because white backgrounds print better and have less catastrophic issues
with display projection, it is often wiser to base a palette on a white or light
background.
Tip
Start all palettes by first choosing a background color. Dark
backgrounds work well on a computer screen. Visualizations with white
backgrounds print better and do not suffer as badly from loss of small
items when digitally projected, though color depth will be lost.
The last set of principles is about neutral colors, saturation, and brightness.
Color neutrality
is a spectrum, where grays are the most neutral of all.
Grayplaysanimportantroleinvisualization.Colorinvisualizationisloaded
with meaning, so unless a color is coded to information, it should generally
be a shade of gray. Sometimes the meaning being encoded is neutral, in
which case it should also be a shade of gray (for example, an unchanged
value in the spectrum of loss and gain).
An important quality of neutral grays is that they are also visually recessive.
They need to be quiet enough to let the important information sing. This
need also applies to the use of colors to represent the information itself. The
