<?xml version="1.0" encoding="utf-8"?>
<page xmlns="http://projectmallard.org/1.0/" xmlns:its="http://www.w3.org/2005/11/its" type="topic" style="question" id="color-whyimportant" xml:lang="pt">

  <info>
    <link type="guide" xref="color"/>
    <desc>A gestão de cor é importante para desenhadores, fotografos e artistas.</desc>

    <credit type="author">
      <name>Richard Hughes</name>
      <email>richard@hughsie.com</email>
    </credit>
    <include xmlns="http://www.w3.org/2001/XInclude" href="legal.xml"/>
  </info>

  <title>Por que é importante a gestão da cor?</title>
  <p>A gestão de cor é o processo de capturar uma cor utilizando um dispositivo primeiramente, mostrando num ecrã e plotando-o ao mesmo tempo que se mantêm exatamente as cores e a faixa de cores na cada um dos meios.</p>

  <p>A melhor maneira de explicar a necessidade de gestão de cor é com uma fotografia dum pássaro num frio dia de inverno.</p>

  <figure>
    <desc>Um pássaro numa parede gelada tal e como se vê no visor da câmara</desc>
    <media its:translate="no" type="image" mime="image/png" src="figures/color-camera.png"/>
  </figure>

  <p>Geralmente os ecrãs sobresaturan o canal azul, fazendo que as imagens pareçam frias.</p>

  <figure>
    <desc>Isto é o que um utilizador vê num ecrã de portátil de negocios típica</desc>
    <media its:translate="no" type="image" mime="image/png" src="figures/color-display.png"/>
  </figure>

  <p>
    Notice how the white is not “paper white” and the black of the eye
    is now a muddy brown.
  </p>

  <figure>
    <desc>Isto é o que o utilizador vê ao imprimir numa típica impressora de inyeção de tinta</desc>
    <media its:translate="no" type="image" mime="image/png" src="figures/color-printer.png"/>
  </figure>

  <p>O problema básico é que a cada dispositivo é capaz de manejar uma faixa diferente de cores. De modo que, ainda que possa tomar uma fotografia em azul elétrico, a maioria das impressoras não poderão a reproduzir.</p>
  <p>
    Most image devices capture in RGB (Red, Green, Blue) and have
    to convert to CMYK (Cyan, Magenta, Yellow, and Black) to print.
    Another problem is that you can’t have <em>white</em> ink, and so
    the whiteness can only be as good as the paper color.
  </p>

  <p>
    Another problem is units. Without specifying the scale on which a
    color is measured, we don’t know if 100% red is near infrared or
    just the deepest red ink in the printer. What is 50% red on one
    display is probably something like 62% on another display.
    It’s like telling a person that you’ve just driven 7 units of
    distance, without the unit you don’t know if that’s 7 kilometers or
    7 meters.
  </p>

  <p>
    In color, we refer to the units as gamut. Gamut is essentially the
    range of colors that can be reproduced.
    A device like a DSLR camera might have a very large gamut, being able
    to capture all the colors in a sunset, but a projector has a very
    small gamut and all the colors are going to look “washed out”.
  </p>

  <p>
    In some cases we can <em>correct</em> the device output by altering
    the data we send to it, but in other cases where that’s not
    possible (you can’t print electric blue) we need to show the user
    what the result is going to look like.
  </p>

  <p>
    For photographs it makes sense to use the full tonal range of a color
    device, to be able to make smooth changes in color.
    For other graphics, you might want to match the color exactly, which
    is important if you’re trying to print a custom mug with the Red Hat
    logo that <em>has</em> to be the exact Red Hat Red.
  </p>

</page>