The nuances of color rendering quality: color models and color gamut.

Posted by ArtisTile Ceramic on

Some customers, when receiving their orders, sometimes notice an incomplete correspondence of certain color shades on the image of the purchased decorated tile with those color shades that they observed on the screen of their computer, considering the same image at the stage of choosing and purchasing their decorated tile.

In fact, such a phenomenon as somewhat inaccurate color reproduction when reproducing the original digital image on a printing device, especially when printing with ceramic toner, takes place. Many factors can affect the transmission quality, but it must be said, that it is impossible in principle to achieve absolutely accurate color reproduction of the original digital image when printing with ceramic toner. By processing the image in a graphics editor, it is possible to achieve a greater correspondence between the original image and the resulting print, but, unfortunately, it is almost impossible to achieve complete correspondence.

Why is this happening? Let's start with the fact that the color on the screen of your monitor is formed by light. This is the RGB (Red-Green-Blue) color model, where almost all color shades are derived from three primary colors: red, green and blue. RGB is an additive color model where mixing three primary colors produces a pure white color. In the RGB color space, when any two colors are mixed, the resulting third hue will be lighter. This is a method of color synthesis based on the addition of colors directly emitting the glow of objects.

Most printing devices work in a different color space: CMYK (Cyan, Magenta, Yellow, Key or Black). This model is a subtractive scheme of color formation (synthesis method based on the subtraction of elements from each other). When mixing different colors, the result will be darker, and the superimposition of all colors on top of each other will produce a black color. This color model works by subtracting a certain amount of light reflected from the medium (for example, from a sheet of white paper).

RGB and CMYK comparison

We should also mention the concept of color gamut. Color gamut is the range of colors reproduced by a monitor or printing device.

Inkjet printers that use liquid dyes, especially in recent years, are capable of printing up to twelve colors, fairly closely imitating the RGB color gamut. Laser printers use four or five primary colors. Ceramic toner printing limits the number of primary colors to four. In addition, most household and even industrial liquid dyes and toners are based on organic chemical elements. Ceramic printing uses toners that are based on inorganic chemical elements (ceramic pigments) capable of withstanding a firing temperature of 800 ° C - 1250 ° C, depending on the type and purpose of the toner, ceramic media and the technology used for decoration. Such pigments have a very high resistance to fading and external influences, but their color gamut is quite noticeably inferior to that of the RGB model, and some individual colors are not reproduced at all, even after image processing in Photoshop.

Comparison of color gamuts of RGB and CMYK models

As can be seen from this figure, the color gamut of the CMYK model, even regardless of the inorganic nature of the ceramic pigments and the influence of high temperatures during firing, is much less than the color gamut of the RGB space.

I hope that now, although somewhat simplified, this issue is generally clarified. In conclusion, I would like to add that an honest, decent and responsible manufacturer of ceramic custom tiles, using hot decal technology in the manufacturing of his products, is unlikely to guarantee an absolute and one hundred percent hit in color, but it will guarantee a beautiful image, resistant to external factors and retaining its color palette for a long time.


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