This effect allows adjusting the image (changing its color
tones, saturation, contrast, lightness, etc.) using three channels: Red,
Green and Blue.
Every channel is represented by a scale with a triangle control.
The parameter can be adjusted in the following way:
-
Shifting the triangle to the right/left leads to
increase/reduction of the corresponding color component in every
image point.
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| Red color increasing in every image point |
Red color reducing in every image point |
-
Enlarge/reduce. Left-click on a triangle's corner
and move the cursor to/from the center of the triangle. By increasing/reducing
the triangle size, you strenthen/weaken this color component. The color
is strengthened/weakened only in the points where it was,
other points of the image stay unchanged.
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| Red color increasing in the red channel |
Red color reducing in the red channel |
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Change the color of the triangle. For this purpose,
left-click on the white circle at the apex of the triangle, and drag it
to another apex. For example, if we change the triangle's color in the red
channel to blue, the red color components in every point of the channel
will become blue.
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| A source image |
Replacing a color in a chanel |
-
Change the color of the triangle to two color
sectors. For this purpose, left-click on the white circle at the apex
of the triangle, and drag it to one of the triangle' sides. For example,
if the triangle in the green channel consists of blue and red sectors, the
new value of the green color component will be calcualted as a sum of blue
and red components. Other color components will not change.
|
|
|
| A source image |
Replacing a color in a chanel |
-
Change the color of the triangle to three color
sectors. For this purpose, left-click on the white circle at the apex
of the triangle, and drag it towards the middle of the triangle. For example,
if the triangle in the blue channel consists of three color sections, the
new value of the blue component for every point of the image will be calculated
as a sum of these three color sections. Other color components on the image
(in this case, red and green) will not change.
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|
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| A source image |
Replacing a color in a chanel |
Attention! |
The triangle control
does not show the result. It only shows the way the points in this
channel will be calculated. |
Hint: To understand it better, you are welcome to read
the mathematic description of the effect ( the red channel as
an example).
As you change the position of the channel's control, the program
recalculates the value of the corresponding points using the following formula:
Rres = ( R * r' + G * g' + B * b' ) * T + C,
where:
Rres – the resulting value of the red component
for this point.
R, G, B - the starting values of the red, green,
and blue components accordingly.
r', g', b' – the area taken by the red, green,
and blue sections on the total area of the triangle control.
Sum r' + g' + b' = 1.
For example, when the triangle is red, than r' = 1, g' = 0, b' = 0,
if the triangle has two sections, the ratio can be: r' = 1/3, g' = 2/3,
b' = 0, if three section - for example r' = 1/2, g' = 1/3, b'
= 1/6,etc.
T – a coefficient depending on the size of the
triangle. By default it is set to Т = 1. If you increase the control
size, then Т > 1; if you reduce its size, then T < 1.
C – a coefficient depending on the position of
the control on the scale. By default С = 1. If you move the control
to the right, then С > 0, to the left - C < 0.
If the starting point was represented as (R, G, B),
the resultng point will be calculated as (Rres, G, B).
The transformations in the green and blue channels are made
in the same way. .
— Channel Mixer