Difference of printed images
Why are the image colors of the monitor different from the after-printing image colors? It is tried to explain the reason for difference of colors. Surely, you have noticed that the quality for the colors of the printed images is different from their quality on the monitor. First, the printer and its low quality is blamed. But, this can be observed even in the best printers. Such a problem is not related to the type of printer and the main reason for this is the difference between the monitor and color systems of printers available in the printing house. In the following, two color systems are explained and we want to explain the reason for difference of colors:
RGB and CMYK color systems.
RGB color system
In this system, the main background color is black. Wherever requiring a special color, it must be added. The combination of three main colors, i.e. RED, GREEN and BLUE create the colors in this system. Therefore, it is called RGB. The more the combined colors, the brighter the resulting color and if all three colors are used completely, the result is white. Consequently, if all three colors are not used, the result is black.
CMYK color system
Actually, in this system, all colors are created from the combination of four colors: cyan, magenta, yellow, and black. Therefore, it is called CMYK. These colors are combined when printing on the paper. The first color is printed first and then the second color and it is continued. Because of the transparency of these colors, what we see on the paper is the result of the combination of these four colors on the paper. There is not the white color in this system, so wherever white color is seen, it means the lack of color.
The difference between the two color systems
These two color models have two basic differences. First, the monitor uses the RGB color model. In this system, colors can have a range of 1-255 (almost16 million colors, i.e. 255*255*255). If this number is compared to the one hundred million colors in the CMYK model, it seems that the CMYK model has more colors. But this is not the case in practice and many colors existed in the RGB model and can be seen on the monitor do not exist in the CMYK model and its reason is the repetition of many colors in 100 million colors of the CMYK model. Therefore, the printer cannot print all the colors you see on the monitor. In most cases, when converting an image created by RGB color model to CMYK color model, it will be noticed that the transparency of the image will decrease. The colors in the RGB model have a great brightness, so that the paper is not capable of representing that brightness in the best possible manner. It should be noticed that even if a file have been designed in the CMYK color model, the printed color of that file will be different from what we see on the monitor, because the monitor is based on RGB and it is not capable of displaying CMYK. The offset printing systemis not capable of printing RGB colors as well.
Therefore, the files sent to the printing house must be in CMYK color mode, so that the difference can not be notified.