by
Pasquale D'Silva aka darkmotion | 26
July 2008
Most everyone who's worked in any media for screen
would (and should) be aware of the importance of the RGB
value system. While it is a concise system for
describing colours, it is somewhat difficult for us to
describe the nature of a colour by amounts of each
channel by eye. So rather than describing the additive
blend of colours, we can describe a colour with HSV
which breaks colour down into more simplistic
characteristics. Let's look at each of these in detail:
Defined by listing
how much red, green, and blue is contained in a single
value. Being additive, the more of each colour that is
added, the brighter (and closer to white) it becomes:
While it's helpful to denote how much of each
colour exists, it is not a very friendly system to describe
a hue shift, saturation, or value/brightness). Try looking
at a colour and try to arbitrarily dictate how much of each
primary colour composes it. Not so easy right?
A colour system that
describes a hue shift, saturation, and value is known as
HSV:
Now that's a lot easier to describe colour with.
Want a colour to be more turquoise? Scarlet? Plum? Just
shift the hue slider until it hits the sweet spot. Need
brightening without losing saturation? It does that too!
With
colours having different natural brightnesses to each other,
preserving luminosity when tinting with hue shifts poses a
problem with contrast. When adjusting a saturation value in
HSV, the value scale adjusts proportionately to maintain the
same amount of brightness.
For example, take a look at the following diagram:
Yellow has a higher natural brightness than purple which
sits on the opposite end of the colour spectrum (which is
easily observed when looking at it in grey scale). What does
this mean? It means that simply lightening or hue shifts
destroy levels of saturation when controlling all channels.
This is because the natural luminosity of red, green and
blue at equal saturations differ significantly. To
compensate the desaturation, the value/brightness needs to
be scaled in HSV to match. It is important to maintain a
strong contrast in brightnesses, so attention to natural
brightness is helpful in picking appealing colour schemes
and palettes.
While
amounts in HSV are not completely relevant for telling a
display how much within each RGB channel is required, it
creates a scale that describes useful properties of colour.
And at the end of the day, it's returned as RGB or
hexadecimal; merely a different way to break down colour
components into locations within a given colour gamut.
The next time you are exploring your favourite image
editor, make sure to check out the different colour slider
modes:
Of course HSV doesn't scale to all digital colour
spaces, but in most cases you should be able to flip over
from the RGB scale. Being able to apply traditional
approaches in picking and applying colour opens up a more
fluid and natural work flow, which can assist the transition
for traditional artists migrating into the digital realm. So
HSV or RGB as a colour refining scale? Obviously HSV! Get
into the habit of tweaking colour with the HSV sliders, and
you will be able to control those all too often fidgety
selectors and pickers in a breeze!
To learn more, the following links should be helpful:
If you have any questions, feel free to
email me,
post a
comment, or find me on the
kirupa forums.
|
A Little About Color: RBG vs. HSV
