 |
The
purpose of this section is to describe the three
methods of "clipping " offered with the plugin
HSL Plus. |
Let us begin by explaining the problem
of "clipping". Only colours in the model (r,
g, b) can be represented in the screen. So to
modify colours, the plugin proceeds in three steps:
1- conversion from (r,g,b)
model into (h,s,l) model.
2- adjustment.
3- conversion from
(h,s,l) model into (r,g,b) model.
Sometimes, a problem appears to the
third step: calculated colors cannot be represented
on the screen, they are "out of gamut".
- For
this problem, the plugin proposes three solutions:
-
nearest color: replace
the problematic colours by the closest representable
colors. This method often introduces unsightly
distortions of tints.
-
desaturation: desaturate
the problematic colours until they are representable.
This method has the advantage to respect at
most luminosity.
- recommended : recommended method
because this one avoids two problems induced
by other methods: namely distortion of tints
and excessive desaturations . However, this method
can provoke a loss of contrast.
To test these three methods, we are
going to apply to an image excessive
parameters : brightness=30 , contrast=50 , saturation=70, hue=0.
Image
Originale |
|
Nearest
Color |
|
 |
|
 |
|
| |
|
|
|
Desaturation |
|
Recommended |
|
 |
|
 |
|
Obviously, i repeat it, parameters
applied above are excessive. For this example, recommended
method is the one that gives the best result. |
