Graphics Reference
In-Depth Information
intensity of color needs to be applied judiciously based on the size of area
that will be occupied by the color. Large swathes of full-intensity colors are
like a room full of shouting people. Sensory overload makes it very difficult
to perceive anything at all. Full-intensity colors should be used only in very
small doses, if at all. Another aspect to keep in mind is that intensity maps
intuitively to magnitude, so when color gradients are used, diminishing
values should approach neutrality.
The
Hue, Saturation, Brightness (HSB)
modelforcolordefinition,also
known as HSV (where V stands for Value), is the most useful of common
color models.
Hue
is what we typically think of as color, the spectrum of
the rainbow.
Saturation
is the degree of color, where a saturation of zero
defines the grayscale spectrum. The
brightness
of a color is a range from
black to full color.
Saturation of zero and brightness of one is white. A simple rule of thumb for
a visualization with a white background is to lower saturation to approach
neutrality,andforadarkbackgroundtolowerbrightness.Thishastheeffect
ofblendingmorewiththebackgroundcolorineachcase.Decreasingopacity
has exactly the same effect, except when translucent items also blend with
other items that they overlap. Sometimes varying opacity is a better choice.
But oftentimes, using saturation or brightness to achieve the same effect
produces less confusion from color mixing that occurs from overlapping
elements of different hues.
Brightness can be varied a bit on a white background, and saturation can be
varied on a black background. But in either case, these should be close to
full value when you encode information. Stay away from dark color sets on
white, or pastels on black.
Summary
Design is essential to getting the most relevant information out of data.
The art of designing an effective graph, however, can seem like a mystical
process with an overwhelming number of options. An understanding of
core underlying principles of visualization design can go a long way toward
demystifying the process and developing a framework for making design
decisions.
Nodes are the most critical elements of a graph. Choosing the right shapes
and size mappings are important factors in success. Symbols help
