In a perfect world, we could just hit the print button and get an exact copy of what we see on our screens. Sadly, this is not the case, and won’t be for a long time.
I’m printing my graphic novel now, and the initial proof from the publisher was less than desired. They do not do any correction to the image, they just print exactly what you send. That’s a huge problem, but it may be hard to figure out why your print looks different from the monitor. For those of you who don’t have a background in digital printing, the world of RGB and CMYK, ppi and dpi can be really confusing. Computer screens are black when you turn them off, and you have to put dots of colored light on them to produce images. How do you put color onto black? In elementary school, we all learned that red and green and blue make white. By changing the ratio of these three primary colors, you can make thousands of variations. And since you can also produce white with red, green and blue, computer screens use the primary colors to make images on your black screen. If paper were black, the world would be simple. But paper is white, so we can’t use red, green and blue ink to print on white paper. Inkjet printers use cyan, magenta, yellow and black ink to print color images. These are the secondary colors, made by combining red and green to make yellow, red and blue to make magenta, and green and blue to make cyan. These secondary colors aren’t as powerful as the primary colors, so they can’t make a true black. Printers use a cartridge of black ink to get the blacks properly deep. Not only that, but cyan, magenta, yellow aren’t as stable and easy to work with at red, green and blue. A slight disproportion of one of these secondary colors will change the result drastically.
Our computer and TV screens work in red, green and blue, RGB. But the printer uses cyan, magenta, yellow inks, CMYK.
The software has to interpret your red, green and blue colors and tell the ink cartridges what proportions of each of the cyan, magenta and yellow to shoot out to match the color of the pixel on the screen. It doesn’t always turn out as expected, because CMYK is less stable. There are color shifts that occur, and other problems. Your color monitor can produce thousands or millions of colors. This is the color range of the computer screen, called the color gamut. But printers will have a much narrower gamut, and so if a pixel exists in the file that has a color that the printer can’t print, it has to print the next best thing. It will print whatever is closest to the color of that pixel. The software will interpret the color as best it can. So if your comic book pages are have a wide range of vibrant colors, make sure you understand that the print might not actually be able to print all of those colors. And that’s not the only problem when you print in color.
When your ink hits the paper, everything changes. Dots of ink bleed, they soften, they spread.
Your image will not look the same on paper as it does on the screen, not just because of the color conversion from RGB to CMYK, we just talked about but because paper is so fundamentally different from a computer screen. Images on your computer screen are razor sharp and lit from behind. Even though the resolution may only be 72 ppi, the images are still sharp and bright. The blacks are a true, deep black. The whites are backlit, bursting with energy from within. The color range is wide, and the pixels don’t bleed. But when the ink hits the paper, it begins to bleed right away and soften the image. Likewise, the whites in the image can only be as bright as the white of the paper. No matter how bight your paper is, it will never be as bright as your backlit computer screen. To see white paper, light has to be reflecting off of it. There has to be a light source, so the intensity of the light source will determine how bright the whites are on your page. Matte paper will reflect less light because it doesn’t have the glossy coating. The blacks, particularly on matte paper, will never be as dark as your computer screen. And the spreading of the ink I talked about results in a slightly blurry image. The weaker light source, combined with the narrow color gamut and the spread of the ink, means that your printed comic book won’t look the same as it does on ComiXology.
I hope this was helpful at explaining why your printed images and comic books look different on paper than they do on the monitor if you just hit print without making any corrections.