Why does your print not match the precious picture you had on your screen?
The quality of the printers is improving fast. Nowadays a lot of color printers have more than four cartridges, making sure all the tones are printed. Yet the extra cartridges are gray or black, never a color, which means there are still colors you see on screen that can’t be printed on paper.
Taking pictures and printing them on your colorprinter can be disappointing. Sometimes the result is NOT what you expected. I’ll give you the reasons for that disappointing result.
The most beautiful shade of blue
I collect cobaltblue glass objects. They are nice in my room as decoration and great to make still lifes pictures with. But I better not print them on canvas or paper, as I do with lots of my pictures, because the result is not good.
I tested the picture shown here on my inkjetprinter and when I saw the greyish blue vases I was really upset. So I sent a little part of the picture to my supplier for a test as well.
He had a better result than I did, obviously, because his printer is a professional one, but still it wasn’t what I wanted.
But can I fix this?
CMYK and RGB
Two different color systems
The article “Colorful design” explains the difference between CMYK and RGB. Why is that important? Because your camera makes pictures in the RGB-colorsystem, but the four cartridges in your color printer are cyan, magenta, yellow and black.
RGB Red Green Blue
An additive color system
Each primary color of the additive system has a maximum value of 255, as shown below. The order is always Red first, than Green and than Blue. All other colors on the screen are a mixture of those three primary colors. As shown in the examples here.
CMYK Cyan Magenta Yellow Key (Key=Black)
A subtractive color system
Printers have four colors in the subtractive system. Each primary color plus black has a maximum value of 100%, as shown below. In the example, the numbers indicate how much of each color is mixed to get the result that you can see.
By the way: the K is for Key and not B for Black, because the B could be confused with the Blue in the RGB system.
Millions of hues
Most CMYK-colors can be converted to RGB, but not all RGB-colors can be converted to CMYK. We can see more colors than the printer or the screen can show us.
The color schedule below is a model to explain the differences. Although it doesn’t represent all colors, you’ll probably get the picture.
However, if you have Adobe Photoshop, you can see beforehand which colors will not convert the way you want them to.
A useful tool In Photoshop
In Photoshop select a color in your image with the tool pipette and go to the Color Picker. Here I selected a very bright green. As you can see there is a triangle in the middle with an exclamation mark in it, indicating that the RGB-color will cause problems when converted to CMYK. Clicking on the exclamation mark will show the CMYK-result.
Mind you, it’s still just an indication. If you really want to know the result, you’ll have to print it. Colors look very different on paper (subtractive colorsystem) than on screen (additive colorsystem).
Greens and blues will cause the main problems. Another trick to know up front where you can expect trouble is by looking at the RGB-values: the higher a RGB value (e.g. Green = 0-255-0) the bigger the chance that the conversion of the color will go wrong. As you can see in the example the RGB value of 0-255-0 is 71-0-100-0 in CMYK. But the much darker green that is displayed after clicking the exclamation mark has the same CMYK-value.
So how about fixing the problem?
The bad news is you can’t fix it completely. The good news is you can limit the problem.
- Using a professional printer is a wise thing to do. It doesn’t has to be your own. Not all pictures will cause you this problem so let the professionals deal with that couple of photographs that are giving you a hard time.
- Use glossy paper or glossy varnish – that will enhance the image considerably.