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Beginner's handbook

RGB vs CMYK: Guide to Color Spaces

By Reading Time: 5 minutes

Imagine a color, any color. It could be bright and vibrant, or dark and dull. You’ve probably seen it somewhere, maybe in your favorite movie or on a cool poster hanging in your office. Combine enough colors and soon you’ve got a cool design. If you’ve ever wanted to put that design on something and sell it, you’ve probably done some tinkering in Photoshop.

The print file you get out of Photoshop and the image as it appears on your t-shirt might not be the same though. Often, the difference has to do with color spaces, and why there’s a difference between how colors appear on our screens and how they look in real life.

In this post, I’ll go in-depth about one of the trickier color-related topics–RGB vs. CMYK color spaces. I’ll break it down by answering some of the most important questions:

  • What are RGB and CMYK and when do we use them?
  • What is the difference between RGB and CMYK?
  • What is the most suitable color space for printing?
  • Is CMYK better than RGB?

Let’s start with some basic color facts. All the colors we can see with our eyes are part of the visible color spectrum. They’re represented in the circle below.

visible-color

Visible color spectrum

Because of technological limitations, our computer screens and other similar devices can’t display every color that our eyes can see. Instead, display screens show colors in the RGB space.

What is RGB?

RGB stands for the three colors Red, Green, and Blue.  The color space uses Red, Green, and Blue light to make new colors. You can see the RGB range compared to visible colors in the picture below.

rgb-color

RGB color spectrum

Each pixel in the digital devices we use has three tiny, slightly overlapping RGB light sources that trick our eyes into seeing just one color when looking from a distance.

So if you wanted to show something yellow, the RGB pixel would shine green and red light together, while leaving the blue one off. The stronger the light intensity, the brighter the colors appear. At full intensity, the combined colors appear white and at zero intensity they appear black.

What’s great about the RGB color space is that it gives you a wide of range color combinations you can play with when creating digital designs.

When is the RGB color space used?

RGB colors are used for digital purposes. Any images that appear on a digital screen will be displayed in RGB. This is important to remember when creating your print files since you’ll most likely do it in Photoshop or similar software.

If you’re Printful customer, we recommend you create your print files in CMYK and then convert them to RGB color space, or, to be exact, sRGB color profile. I’ll explain the exact reasons later, but first, you might be wondering what CMYK is.

What is CMYK?

CMYK stands for Cyan, Magenta, Yellow, and Key (which is just another word for black). It’s basically the opposite of RGB; it uses colored ink to mask colors on a light background. This light background (usually white) reflects light, so each layer of ink applied subtracts from white light to make new colors.

For example, if you combine Yellow and Magenta (meaning subtract yellow from magenta), then you get Red. You can combine any two Cyan, Magenta, or Yellow colors to create one of the three RGB colors.

If it’s confusing, just try to think about drawing with colored pencils. If you combine two different colors, you’ll get a third. It’s the same idea behind CMYK.

When you combine all three colors, you get grey. Since we also need black, it’s the fourth color. This is also why CMYK is sometimes called the four color space.

Compared to RGB and visible color, the CMYK range looks like this:

cmyk-color

CMYK color spectrum

When is the CMYK color space used

CMYK is recommended for any printed material. This includes all of Printful’s products, from apparel to mugs, posters, and more.

Why do we use CMYK for printing? It reflects the colors more accurately.

What is the difference between RGB and CMYK?

Key DifferencesRGBCMYK
What does it stand forRed, Green, BlueCyan, Magenta, Yellow, Black
What's it used forDigitalPrinted
Variety of colorsLots of colors, vibrantFewer colors, sharper
Photoshop settingsDefaultMust convert from RGB to CMYK
Accepted print fileYESNO

I like to think of RGB as a lit match in a dark room, while CMYK is a picture of the lit match in the dark room.

With CMYK, color intensity is not as flexible as in RGB. It’s just impossible to replicate on ink paper or fabric the same intensity and brightness that a digital display can show.

This means some RGB colors will show up differently when printed in CMYK. The software you’re designing in (Photoshop and others) is set to RGB color space by default (in most casses: sRGB color profile specifically). That’s fine if your designs are only going to appear online, but printed designs need to be done in CMYK. You can read Printful’s Color Matching Disclaimer for more details about this.

We recommend using CMYK when designing print files for a few reasons:

  1. RGB files tend to be smaller
  2. Only advanced software has the option to design in CMYK

How to convert RGB to CMYK

This depends on the software you use and which version you have, so I recommend finding a tutorial online for the software you have. Here is a short RGB to CMYK Photoshop CC tutorial.

Is CMYK better than RGB?

CMYK and RGB have different uses, and it’s important to know when to use which. Since we’re focusing on printing, we want to stay within the CMYK range. However, technology is advancing and Printful’s printers can already print colors outside of the usual range, although we still suggest sticking to approved methods. What happens if you don’t convert your RGB colors to CMYK?

Let’s take a look at this design as it appears in Photoshop:

cmyk-printed-example

Digital design example

As you can see, the colors stand out and the shadows are visible. Now let’s compare it to a printed t-shirt with the same design:

https://static.cdn.printful.com/blog/wp-content/uploads/2019/02/comparing-colored-corrected-shirts.png

Not color corrected vs color corrected

Clearly, it doesn’t look the same. The t-shirt on the left looks flat and dull and hasn’t been color corrected. The t-shirt on the right matches the vibrant colors of the original design, it was color corrected.

You can see how much of an improvement this is. The colors stand out, they’re brighter than they were before and the printed version really captures what the original design was going for.

So how do you avoid printing the wrong colors show up on your products? We recommend ordering color swatches. These are samples of different RGB colors as they appear on printed material. This will help you determine how to color correct for print. 

Color swatches look like this:

https://static.cdn.printful.com/blog/wp-content/uploads/2019/02/color-swatch-example.png

Printful color swatch example

They come on a black or a white t-shirt and have multiple different RGB colors printed allowing to see how the colors look on your screen compared to real life. They also come with the numbered color codes for Photoshop for you to manually adjust colors if necessary. You can download the digital files of the swatches below. If you feel comfortable using photo editing programs like Adobe Photoshop and Illustrator, you can create your own custom swatches with the colors you use more frequently and make a sample order with those.

Download Printful’s Color Swatches

Combine your colors

Be brave and experiment with your color designs. Figuring out the right ones might take some work, but you’ll get there soon enough. Just remember these differences between RGB and CMYK and you’ll be a color expert in no time!

And don’t worry if you’re nervous about setting up your design files correctly, we’re more than happy to help you with that as well. Feel free to contact our Design Services team, they can assist you in navigating this sea of color.

You can find me devouring the dusty marigold pages of my First Edition Wheel of Time collection while enjoying a plate of fluffy pancakes next to my adopted goldfish, Harold.

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    1. Filip Pejanović Post author

      Hi Serge, you can download a digital file of the swatch values from your Printful account. Go to Printful dashboard > New Order > Select your store > Create a sample order > Add product > New Products > Choose any product > Upload file > Choose file > Click the “Download” icon.

      1. John Kirkham

        Or to put it another way, no. Those files are there (hidden in that weird complicated place) and they do help, but it would be way more helpful to have colour palettes that could be loaded into illustrator/photoshop. Everybody wins if you make it easy for your customers to use colours that print well.

        1. Filip Pejanović Post author

          Hi John, thank you for the feedback, it’s a good idea that we’ll add to our to-do list! As a temporary fix, you can download the digital versions of the swatches at the bottom of the article.

        2. Miguel

          Yes, please, We are in the same problem trying to create acurate and more complicated colour designs.
          It´s almost a must to have a photoshop colour profile. CMYK still far away from your printers colour profile.
          Looking forward for this improvement.
          Thanks

  1. Jason

    Thanks Filip. Very helpful, including the swatch download. (Now I won’t have to carry around my cut out T-shirt samples, since I travel a lot!) But quick question. Assume we’re building in Illustrator, in RGB already, and we’re using “fills” of backgrounds created from the RGB colors you specify. Then exporting as PNG directly from illustrator. That workflow should already be color correct, yes? (Essentially, there’s not CMYK in this process, as it’s all built from RGB colors based on your exact color specs…)

    Thanks! -Jason
    @thenomadexperiment

  2. Tj

    Thank you for the article. I much prefer this format rather than the instructional videos. I do have a couple of questions though.
    Is the PNG file the only file type that is accepted?
    If so, why? If you are converting these files back to a CMYK format, why not accept vector files already in CMYK?
    I am grateful for the electronic color swatch samples and for the printed versions. I found it difficult to find and order them. The links for the white shirt, black shirt, etc. were helpful but once you click on one and start the order for it you cannot get back to those links to easily put one of the other products in the same order. I still don’t know how to order one of the swatch samples without using those links.
    Wouldn’t it be helpful to have a swatch sample matrix that shows these RBG colors with their closest CMYK colors? As it is, if there is any depth to the design you are creating, it is a lot of work to have to go back and color correct into RGB values when you know that you are going to turn right around and turn it back into CMYK.
    Thank you for your time and assistance.

    1. Filip Pejanović Post author

      Hi Tj, thank you for the questions and the feedback, always nice to read that the article was helpful.

      Yes, please send us PNG files. This is to make sure there aren’t any layering errors when working in Photoshop. Sometimes our machines can print the hidden layers and cause the design to turn out differently.

      As for the color swatches and color correcting, you make a good point and I understand that the process can be tricky, we are working on streamlining this and making it easier for our customers to use.

  3. Michael Doyle

    Before reading this information, I sent along flattened PSD files in Adobe RGB (1998) to be used in my posters. I had previously used a wide-format Epson printer using Epson UltraChrome inks. The results were excellent. Is it OK to use Adobe RGB (1998) settings for my Printful poster files? Or is there a preferred RGB profile? Should I resend my files as PNG files or would my flattened PSD files be OK?

    Thanks

  4. Valeria Ferreira

    Hi there, please I am creating simple black text and according to the swatch palette, I should use RGB 39,37,37. I have created a sample print file with the mockup generator to compare and the file comes out RGB 51,36,37, which looks a better black. Is there any specific rule for black print colour on mugs and T-shirts. Thank you very much.

    1. Edward Zarins

      Hi there again, I misunderstood your comment at first. Sorry about that. For true black color you should use RGB 0:0:0. 🙂

    1. Giedrė Kronberga

      Hi Amir, just click on the text “Download Printful’s Color Swatches” and it will be with you in no time 😉

    1. Filip Pejanovic Post author

      Hi Pamir,

      What would you like to print your photo on? We don’t print photos directly, but we can print the photo on a poster, t-shirt, or other products.

  5. Michael

    Hello,

    Thanks for the guide, is very helpful. The issue that I see here is this:
    Let’s take the black t-shirt of the article’s example. I want to send the right colours but to do that I need to upload the wrong ones, at which point Printful will give me a mockup with a certain scheme of colours that will be printed on a different colour. So no matter what, there will be a difference between the colours that my customer sees in the mockup and the colour printed right?
    So I cannot use the mockups from the file that needs to be printed, I need to link my mockups with the old colour to the product with the adjusted colours, and the latter will never be seen by my customer right?

    1. Edward Zarins

      Hey Michael,

      The difference between your original colors and the corrected ones shouldn’t be so noticeable in the mockup generator. 🙂

    1. Giedre Kronberga

      Hi Desi! We suggest you design your file within the CMYK color space, but convert the file to RGB for printing.

        1. Madara Zute

          Hi Irena,
          If you’re working in Photoshop, you can switch between the color modes RGB and CMYK in “Image” -> “Mode”
          You can also check “Color Settings” under “Image” to see what color profiles you’re using.

  6. Kareem

    THIS IS WHAT I NEED, THANKYOU SO MUCH!! i like wandering around printful blog bcs its full of good articles.
    quick question sir, do i need to do color correction if i use white underbase? thank you.

      1. Cricket

        I am attempting to figure out the color correction, but the video link posted here and in the disclaimer page both go to a YouTube video that says “Video unavailable. This video has been removed by the user.” Do you have a corrected link, please?

  7. Ali

    Hi Printful Team,

    a simple question: I have ordered the white and black shirt with the Printful Color Swatches on them. I make my designs with Procreate on iPad. For example, if I have a simple design consisting of three yellow stripes in three yellow tones on a white shirt and I use the RGB code of three different yellow tones given in the swatches, how would Printful know which three yellow tones (RGB codes) have I chosen in my design? The design will be uploaded as PNG. Is Printful able to identify the exact RGB code of the color from the PNG design?

    Thanks for the help
    ali

    1. Madara Zute

      Hi there Ali,
      Yes, we can pick up your color code from your PNG file.
      We suggest you design your file within the CMYK color space, but convert the file to RGB before saving. For best possible accuracy, convert the file to sRGB IEC61966-2.1 color profile so that your colors stay within the gamut.

  8. A C

    Printful
    I am a photographer and work in sRGB, as thats what my printing lab was set up for. If I create good 300dpi+ rez files in sRGB Am I going to see a big difference in color shift in Images that will be printed on Tshirts?
    Thanks
    AC

    1. Madara Zute

      Hi there,

      There shouldn’t be too much of a difference but bear in mind that the same color value will look a little different on when printed on 100% cotton vs. a fabric blend.
      Similarly, the same color value will look different when printed on a light vs. dark colored t-shirt.

  9. Steve Wyrostok

    Hi, and thanks. Two questions please.

    1) When designing for DTG in CMYK space in Photoshop, what is the proper and most compatible Working Space in Edit > Color Settings > Working Spaces that will survive the conversion to sRGB to upload and reconvert back to CMYK at your end? (i.e. Coated FOGRA27, US Web Uncoated, etc.). I am guessing that it would be best to use the same CMYK Working Space you use at Printful?

    2) When designing in CMYK and trying to target the RGB values in the Printful swatches, I am noticing many colors show a close-but-not-zero value in one or more of the CMYK colors. Question: does it help to just go ahead and sero out any CMYK values in that case, in order to use the fewest ink colors, potentially resulting in a better DTG output by reducing registration problems?

    Thank you!
    Steve

    1. Madara Zute

      Hi Steve,
      1) I suggest you start with RGB color space and keep an eye on the colors that are being used. If one color or any color gradients (the gradient effect) are out of gamut, that is noticeable right away (https://prnt.sc/pvee5p).
      2. We suggest working with RGB color space and we urge you to check RGB color values rather than CMYK. For example: if you want to print a pure black background/text, then using CMYK colors 0% 0% 0% 100% (K for blacK), these elements will come out as dark gray (https://prnt.sc/pver48 ). If you want to get the deepest black, you would need to use RGB: R0, G0, B0 (https://prnt.sc/pvet7y). However, we always use white underbase for darker garments so black on black will still look gray.
      We also suggest ordering our pre-made color swatches on a sample product.
      If you have further questions, please reach out to support@printful.com.
      Hope this helps! 🙂

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