We all use color printers to bring our digital images to life. But not a lot of people know how color photographs are actually printed. Color Images are created from 2 types of color combination RGB and CMYK, but only one is used to print image. Do you know why and what is the difference?
For those who do not have idea about them here we explain about both the color models. As it is important to under the color modes first only then we can have a fine quality print.
In our last article, we already discussed about DPI and PPI where CMYK and RGB color models were also discussed, but not in detail. In this article we will understand them better and their usage.
Additive and Subtractive Color
RGB Color Model (Additive)
The RGB Color model is an additive color because as you add more primaries in various ways to reproduce a broad array of colors, more visualizing and brighter the image will be and background will be Whiter. It directly corresponds to how devices display color.
The particular reason why RGB is used for the Digital purpose is because of the Tristimulus Theory. In this theory, eyes are most sensitive to Red, Green and Blue light, and therefore we can approximate the colors we see by using these combinations. It emits light to display colors over the screen. When the reflected light contains a pure mixture of RGB our eyes perceives white and when there is no light emitting, our eyes perceives black color.
This model as discussed produce more variants and colors that is why this color model is used in projection and display systems that include computer screens, mobile device screens and other portables.
Its used in Raster graphics also and used by designing softwares like Photoshop to print images. Whereas, CMYK is used for printing and not digital images.
Let us see why and how?
CMYK Color Model (Subtractive)
CMYK Color model is a subtractive color model because, unlike light which is additive and adds up to white. Pigments are subtractive and combines into black. In this model when Red, Green and blue are added gives us black pigment. Black pigment here is used to subtract the brightness of the colors.
CMYK stands for Cyan, Magenta, Yellow and Key that is Black respectively. This model, the whole thing is precisely opposite to the RGB color model. RGB is an additive because it gives us white whereas, CMYK masks the presence of white and gives us black as subtractive model. Here CMY are the primary colors of pigment. CMYK is used in printing, and brochures, business cards, osters, books, or magazines.
So, let’s understand this concept by an example:
Say you are wearing a red shirt when it’s hit by white light that we now know is made of different colors. What happens is your shirt absorbs all the colors that hit it, except for red, hence appearing red.
So, the color equation for a red shirt would be:
White – Green – Blue = Red (R)
Let’s take a similar example: So, if the color of the shirt is blue then it would absorb all the colors that hit it except for blue and we see blue
White – Red – Green = Blue (B)
And finally, if we were wearing a green shirt then the equation becomes:
White – Red – Blue = Green (G)
Similarly, when coming on to CMYK color model because as we know it is subtractive as it gives us black when all primary colors are added. If we subtract the primary additive colors from White, we get CMY that are subtractive in nature. Let’s see this in equations:
White – Red (additive)= Cyan (C)
White – Green (additive) = Magenta (M)
White – Blue (additive) = Yellow (Y)
Cyan + Magenta + Yellow = Black (Subtractive)
WHY CMYK IS USED INSTEAD OF RGB TO PRINT IMAGES?
Talking about RGB, CMYK colors and which one is preferred for printing. Let’s take example from our day to day life, when we see a picture on TV screen or computer monitors they look amazing as colors are created additively, meaning by mixing light and 3 colors Red Green Blue.
RGB emits light and offers more color range but this concept doesn’t work when we want to print an image. RGB fails to give a detailed image and lacks to print the spectrum of colors.
On other hand, as print begins with a white page CMYK is used. CMYK with its smaller color space creates a continuous spectrum of colors with printed media where RGB fails. When red, green and blue inks are mixed together they produce a smaller range and make the image blurry.
As opposed, CMYK inks control the RGB effect that is reflected from white paper. When CMYK is used over a white paper, they counterpart the additive colors. As we know, inks don’t produce light, they reflect light.
The makers realized this when 3 subtractive primaries are added, they result in brownish color. But, when black ink is added to the mixture, it adds more intensity to the prints. So that when printing either the images or the huge billboards the quality stays the same and seems more visualizing to our eyes.
Many of the designers gives print in CMYK. They design the digital image in RGB mode. And, before printing they convert the image to CMYK. WHY?
Converting from RGB to CMYK make the image larger by three times but it doesn’t add even a small amount of detail to it. This is because CMYK printed images are already more detailed in comparison to RGB. As the image is already 3 times bigger in working size it by default makes it more detailed. And by default, if the images are in RGB then drivers will convert the model in CMYK.
We hope you have now understood why CMYK is used for prints and images.
Above Image shows the difference between the digital images in RGB and CMYK models. Tell us in the comment section which one will you prefer over digital media.
And, in our next article, we will explain more about what fonts, papers, and printers should be used for printing. So, stay tuned and we hope you like this article!!
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