How to properly adjust color in GIMP

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:

  1. Colors are not intrinsic properties of objects but of light.
  2. Without light -total darkness- no color perception
  3. 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.

Color Additive System











Additive model of red, green, blue colors.

Additive Color

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



Continued ...

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  1.   elav <° Linux said

    Great, I wanted to continue reading .. Masterful Tina UU

  2.   Ares said

    Waiting now for the second part =)

  3.   Perseus said

    It's not fair, first you raise us to "heaven" and in a matter of seconds "lower" us XD. I'll be waiting for the continuation 😉

    PS If you could give me a tip to match colors it would be appreciated (either an application for linux or manually: P)

  4.   KZKG ^ Gaara said

    Great Tina 😀
    Let's see if I can learn to use ... at least moderately well GIMP HAHA, I've always been a disaster when it comes to image processing ^ _ ^ U

  5.   Tina Toledo said

    Hello Perseus:
    The idea is to present the items in "small bites" so that they can be more easily digested. I am trying not to use the technical language of graphic arts because I am aware that many here know and master when it comes to operating systems, but not many know about Color Theory.
    Now, if you feel that I'm going very slow, tell me and I make the deliveries more extensive, just keep one thing in mind; I am trying to summarize in four chapters what it took me a semester to learn at the University.

    GaaraAt least in color I assure you that after this you will give more than one return to many who claim to be graphic designers.

    1.    elav <° Linux said

      Good Tina, because I love graphic design, web design and photography. Let's see if I'm excited now and I start with the help of your articles 😀

  6.   smudge said

    Didactic, interesting and entertaining.
    Thank you

    1.    Jhals said

      That is why it would not matter if Tina did more extensive topics so that we all learn something = P

      For my part, I enjoy reading your articles and, I know that many more do too 😀

      Good luck and thanks for the articles tina.

  7.   Tina Toledo said

    The second part is already in the review tray ...

    1.    KZKG ^ Gaara said

      Right now I review and approve it 😀
      Thank you so much for everything 😀

      1.    Courage said

        It is better that you leave it directly like me, more than anything you save work

  8.   Lucas Matias said

    Funny, with this one realizes the differences between an amateur (me) and a professional.
    Very good!

  9.   Courage said

    Luckily you stayed.

    Interesting article, so the Gimp does not complicate me as much as it complicates me

  10.   oleksis said

    Wow! Color theory, graphic designers ... with this series of articles we will surely be better using the GIMP. Thank you!

    Greetings from FanBoy # 1 from Tina