Trucos de diseño para diseñar como locos

A space of possibilities: CIELAB

In one of my first posts I talked about the main color modes and features, see here. In this publication I focused on the two main color spaces that designers usually work, RGB and CMYK these are neither the only nor the most appropriate available for all tasks.

One of the biggest problems that a designer can find  working with documents is the loss of image information when changing the color space. With few exceptions all the color mode changes that we conduct are totally irreversible, ie, the image information in the documentwill be altered to the detriment of the original information. Only in the times when we move from a lower bit depth to a greater, for example, from grayscale to RGB, the color informationof the document will increase compared to the original state and thus the color informationnot be damaged.

Another clear case of loss of color information is changing RGB to CMYK. As I said in theabove-mentioned publication, in all those works that are to be printed is essential to convert images to CMYK before producing the PDF so that we can prepare properly. In color theory‘s post describes how and why the color models RGB and CMYK. A practical example of this description is to convert an image from one mode to another. As soon convert a CMYK document image we can see an immediate loss of saturation due to the inability of the CMYK space to achieve the most intense colors RGB. This loss of color information is not due to a change in the bit depth, but has been designed as the composition of the range of colors in the color space itself.

A widespread custom among many photographers and designers is to use the CIELAB color space, usually called Lab as an intermediate workspace retouching process, not to be confused with Hunter Lab, which differs in that it uses root Hunter Lab square to calculate the result using tools that CIELAB cube roots. The CIELAB color space (also known as L * a * B*), was designed with the intention to reproduce as accurately as possible the range of colors the human eye can perceive, on the assumption that recipients the human eye to perceive color because of the following pairs of opposites:
  • Light-darkness
  • Magenta-green
  • Yellow-blue

For this reason, unlike RGB and CMYK spaces consisting of color channels respectivelyadded or subtracted to cover the largest possible color gamut, CIELAB is made to L channel the brightness of color, the channel a that determines the position between magenta and green and channel b which does the same between yellow and blue. This channel architecture despite being less intuitive at first sight, greatly facilitates the task of retouching images.

Compared to the color modes RGB and CMYK, CIELAB can reach less numerical values ​​per pixel, however, can describe many more colors than both spaces, including colors that do not exist in the real world. Information loss is almost imperceptible when converting an image to the CIELAB color space. The picture below shows a simple gradient in RGB, CIELAB and CMYK, respectively.

Of course, as it has been made ​​clear in other publications, who must work in print production usually choose to convert the images to the target color mode so as to make it work retouching the image as printed. Anyway it does not hurt to know and experience the possibilities offered by this magnificent color space, which are numerous.


Links: wikipedia, MiMoriarty

About mimoriarty

Diseñador gráfico multidisciplinar; me gustaría trabajar y compartir experiencias con diseñadores de todo el mundo

One comment on “A space of possibilities: CIELAB

  1. Pingback: Make contrast with CIELAB « MiMoriarty

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This entry was posted on November 21, 2011 by in Consejos, multilanguaje and tagged , , , .

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