Matching and finetuning colors
Matching and finetuning colors is not so simple as it looks. That is because changing colors in a camera works
different if you compare it with painting. It is important that you realize that the cells from the sensor (photovoltaic
cells) do not carry any color information, only luminance information. In other words: the cells will make colors in
the picture more brighten or darker in such a way that the balance between the colors shifts.
You need to know also that the processor in the camera, for example, makes everything in the red parts red. That
does not mean that everything in the red parts IS red! Even if there are a few pixels green or blue, the sensor sees it
and will make them red as well. That is why colors can look different in a camera, then when you are painting.
1. There is no database or any tutorial that can help to match colors between specific camera systems of
different manufacturers. Every camera system works different and so the color matrix does. Changing
a number in a cell, for example, in 256 in the matrix of the CM70 series camera, does not mean that this
will change in exactly the same color in the picture from an another camera.
2. Practice a lot to learn for yourself what the best settings are to match the colors between the CM70
series camera and a camera from an another manufacturer.
3. Read the paragraphs "channels and signals," "subtracting and adding colors" to learn how the matrix
works.
Subtracting colors
You can subtract colors using numbers above or below zero in the same cell or in a cell of the same row.
1. For example: If you change the number in the green channel > Red signal in a number above zero, it means
that you are subtracting the red signal from the green channel, making green parts purple, because the
camera sensor removes red into the green parts of the picture. Red and yellow parts become more green, as
the red signal is decreased leaving a green tint behind. I you have a sharp eye, you can see that other colors
in the picture become slightly lighter. By changing the same number in a number below zero, you have the
same result, but other colors in the picture become slightly darker.
2. If the number in the Green channel > Green Signal is changed with the same amount as in the Green channel
> Red signal, green is subtracted from the picture, removing the greenish tint from the yellow and red parts. This
makes the colors as they where before, but less intense and darker (because light is removed and not color).
Remember that:
1. +256 in G-R = Red signal is subtracted from the green channel, changing the balance between green
and red towards green. This means that red pixels in the picture will turn slightly into green and since
there a lot of red pixels are in red and yellow parts, a greenish tint is "left behind" in the picture.
+256 in G-G = Green is subtracted from the green channel, changing the balance between red and
green as it was by removing the greenish tint from the picture. Since light is removed from the picture,
colors become less intense and darker.
2. +256 in a cell makes the picture slightly lighter, while -256 in a cell makes the picture slightly darker.
3. Subtracting a color from the picture affects the colors from the whole picture, because there are also
pixels from that color in other colors in the picture even if you cannot see them. See the pictures below:
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