I am often asked if it’s better to work in RGB or CMYK, particularly if the final product is going to print. There’s no black and white answer to that question (forgive the pun). Instead, there are a number of factors to consider, and they will be covered in this post.
Before jumping in with advice, a little background is called for.
How Does RGB Work?
First, RGB is known as an “additive” color model, meaning you start with Black when RGB = 0, 0, 0 and start adding color until you end up with white when RGB = 255, 255, 255 (8-bit). You will note, in an act of color symmetry, that R+G = Yellow, G+B = Cyan, and B+R = Magenta – the primary colors of the CMYK color system.
How Does CMYK Work?
CMYK is a “subtractive” color model, where you start with white paper and a CMYK percentage of 0,0,0,0. When you add color, you are subtracting from white until you end up with a rich black of CMYK = 100, 100, 100, 100.
Why does the RGB model have three colorants while CMYK has four?
It turns out that commercially available dyes and pigments have contaminants that prevent them from achieving a pure Cyan, Magenta or Yellow. So if you combine CMY you typically get a dark muddy brown or a charcoal gray. Only by adding black ink (K) can you achieve the dark black we all expect. As an added benefit, a single black ink is less expensive than 3 combined inks.
The two applications that I most frequently come across in my travels working with photographers and designers are Adobe’s Photoshop™ and Illustrator™. Both offer the option to work in RGB or CMYK. (Photoshop also offers Lab, but that’s for real geeks and outside the scope of this post.)
Photoshop’s origin was as a retouching tool for photographers, and thus the default color mode has always been RGB. Illustrator’s origin was as a design tool for print designers, and its default color mode has always been CMYK. So if you don’t mess with the default settings, and many don’t, you will end up working in RGB in Photoshop and CMYK in Illustrator.
But there are more compelling reasons to consider in choosing your color mode than simple inertia. Here are some arguments in favor of working in RGB to be followed by some in favor of CMYK.
Why Work in RGB
1. Multiple final destinations
Most graphic arts professionals today are not sure where their work might finally appear. But it’s a safe bet that the internet is the most popular destination. And RGB, specifically sRGB, is the color mode for the internet.
A slightly more subtle issue occurs when multiple print destinations are involved. For instance, an image could be destined for an inkjet printer for Point of Sales purposes as well as a CMYK printing press for a print ad. Most inkjet printers have a substantially larger color gamut than a printing press. So if you work in Creative Cloud’s default CMYK working space (U.S. Web Coated SWOP) you are throwing away a lot of color that would otherwise be available on an inkjet printer. In addition, most inkjet printers are controlled by a RIP (Raster Image Processor), which will happily accept RGB or CMYK files. Thus, the safest option if you are not sure about your final print destination is to stay in RGB.
2. Larger color space
In a variation on the theme of the previous paragraph, most RGB color spaces are larger than CMYK color spaces, so if you work in RGB you preserve more of your colors. That then begs the question – which RGB color space? The Adobe default is sRGB, which with a volume of 832K is substantially larger than most CMYK spaces. Another RGB color space even larger than sRGB is AdobeRGB (1998).
And larger still is ProPhoto RGB. In fact, at 2543K volume it’s so large that its outline can not be properly shown in my 2D projection software below. ProPhoto is sometimes used by photographers as an archival color space, since it is so large, there is no worry about any of your colors getting clipped. Though to ensure gradients don’t suffer banding, it’s necessary to work in 16-bit with ProPhoto, which doubles that amount of space each file takes on your hard drive. Either way, ProPhoto is not a good color space for doing editing. The color space is so much larger than what can be shown on your monitor that you run the risk of degrading your image by making changes in ProPhoto that you cannot see on your display.
With sRGB being so much larger than CMYK color spaces, there doesn’t seem to be any downside to just working in this default setting, right? Alas, it’s not quite that simple. Even though sRGB is more than twice the size of a typical inkjet printer gamut, there are areas – in Cyan and Yellow/Orange – where the inkjet’s gamut can exceed sRGB. That’s why many graphic arts professionals prefer to work in AdobeRGB, which more or less incorporates all printable colors. Go to our separate blog post to learn how to change your Adobe color settings.
3. Lightroom™ is RGB-only
While Photoshop and Illustrator are the two applications I see graphic arts professionals most commonly using, the fact remains that many people use Adobe Lightroom for editing photos as well. And Lightroom does not support CMYK mode.
4. Easier to retouch with 3 variables than with four
Some people say it’s just easier to think in three colors rather than four. Makes sense to me. Also, there can be a variety of CMYK combinations that will achieve a given color, whereas there’s usually just one RGB combination – another simplifying factor.
Why Work in CMYK
Though I think I’ve made a strong case about the value of working in RGB, there are still instances where CMYK has advantages.
1. Controlling your print build
If you know your final destination, and it’s a printing press, there can be a strong reason to deliver your print provider a CMYK file. This allows you to control the CMYK build of your file. For instance, it might be preferable to build a gray color out of K only instead of CMY + K. Printing presses vary through a press run, a 3-color gray color that starts neutral might shift warm or cool in the course of a press run. If the color is built out of K only, it is less likely to shift. Or if you have small type that is built out of CMY + K, it may have registration problems. Not an issue with K-only builds. Lastly, as stated earlier, grays or blacks that are built mostly out of K use less ink and therefore cost less to print.
2. You are used to working in CMYK
Lots of designers and retouchers have spent years working in CMYK and are more experienced and comfortable with that color mode. Sometimes the best tool is the one with which you are most comfortable.
FAQs about RGB vs CMYK
1. So, in conclusion, is CMYK or RGB better for printing?
Generally speaking, RGB is a better color mode for doing your retouching and design work. But there are specific instances, like controlling your print build, where CMYK has advantages.
2. Should I use RGB or CMYK for the web?
This is pretty much a no brainer. RGB is the native color mode for the web, where the destination is RGB monitors and devices. Generally speaking, most images posted to the web are in sRGB color space.
3. Can RGB make any color?
4. When was RGB invented?
5. Which RGB profile to use in Adobe?
6. Why are CMYK colors so dull?
7. Are Pantone colors CMYK?
8. Can a CMYK printer print RGB?
9. How does CMYK differ from CCMMYK?
10. Why is CMYK subtractive?
As stated in the first part of this article, in the CMYK model you start with white paper and add colorants. The more color you add, the more you are “subtracting” from white. When you add 100% CMYK you have subtracted all the white and end up with black.
Summary
Generally speaking, it’s a good practice to do your image editing and design work in RGB. Though there are specific instances where CMYK might be preferable.
If you’ve made it to the end of this article, then you probably care enough about your color to want a properly calibrated monitor. We made TruHu an easy-to-use monitor calibration app and a cost-effective alternative to other solutions. We invite you to give it a try.
