How to properly adjust color in GIMP
When we were discussing the possibilities of GIMP, in the subject GIMP ... where yes and where sometimes, as a useful tool for graphic arts something we all agree on is that to make color adjustments in mode RGB is very good. Therefore, I will try to develop this topic with no other intention than to create a guide that can be useful to those who are new to these arts of digital color.
I.-Why do I have to adjust the color?
Well, first we have to understand what color is and, most importantly, how we perceive it, to know why a series of compensations must be made for a device -a PC monitor or digital printer- represents it as close to reality.
What is color? Color is an attribute that we perceive from objects when there is light. Light is made up of electromagnetic waves that travel at about 300.000 kilometers per second. This means that our eyes react to the incidence of energy and not to the matter itself.
What does this mean? In plain words:
- Colors are not intrinsic properties of objects but of light.
- Without light -total darkness- no color perception
- We perceive colors because objects have the property of absorbing a part of the spectrum of light and reflecting another part.
Now, it must be clarified that the human being can only perceive a part of those electromagnetic waves of light, we call this perceptible part "Visible Spectrum" and are those whose wavelength is between 380 and 770 nanometers.
Why RGB? For a long time man has searched for a way to capture and reproduce color trying to get as close as possible to how he sees it in nature, the two ways "Mechanical" or artificial to do so are the calls Additive y Subtractive. The word RGB comes from Red, Gren y Blue -Red Greenand Azul- and corresponds to the way Additive to reproduce the color.
Additive model of red, green, blue colors.
How the image is reproduced in the RGB system
For now we will not analyze, for a matter of time and in order not to create confusion, the system Subtractive and we will specifically focus on RGB (Additive), which is the one we are going to use in GIMP, since this is the system that is used to reproduce the color in our monitors and it is the way in which the cameras capture it.
"Very well Tina… All that choro is very good, but why do you have to adjust the color? ", my two readers will say.
I will try to explain it in a way that is understandable to everyone: when we go to a household appliance store, it is very common that we see many TV sets turned on and that, although they are tuned to the same channel, the colors look different. This is due to a physical phenomenon called Dynamic Color Range which is nothing more than the ability of each device to represent an area of the visible spectrum of color.
Thus, for example, two cameras can capture different color ranges regardless of their resolution in pixels per inch.
This graph shows how two devices -A and E-
have different dynamic color ranges RGB