RGB vs CMYK for Print on Demand: How to Keep Bright Colors on Custom Merch
What RGB and CMYK mean, why you should not convert your file to CMYK for print on demand, which colors change in print, and how to keep a design bright on shirts and hoodies.
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Every print guide mentions RGB and CMYK, and most of them end with the same advice: convert your file to CMYK before you print. For print on demand that advice is wrong. Here is what the two words mean, what actually happens to your colors between the upload and the shirt, and what you can do to keep them bright.
To see which colors in your own image will change, use the free print color checker. The image is not uploaded.
What RGB and CMYK mean
- RGB (red, green, blue) is how a screen makes color: three small lights per pixel, added together. All three at full strength make white.
- CMYK (cyan, magenta, yellow and black) is how a printer makes color: inks laid over a white surface, each taking some light away. All of them together make something close to black.
The two cover different sets of colors. A screen reaches further into pure, glowing greens, blues and violets than any ink can. Those colors have no CMYK version, so a printer swaps each one for the nearest color it does have.
| Color | On screen | In print |
|---|---|---|
| Neon green, electric blue | Glows | Clearly duller |
| Hot pink, bright violet | Glows | Duller, a little darker |
| Red, orange, yellow | Bright | Close, slightly softer |
| Earth tones, pastels, skin | As shown | As shown |
| Black, white, grays | As shown | As shown |
Should you convert to CMYK for print on demand?
No. Print-on-demand suppliers such as Printful ask for RGB files in the sRGB color profile. Their printers have their own software that turns each file into ink for that printer, that fabric and that ink set, and it does that far better than a general conversion on your computer can.
Converting first throws color away twice: once when you convert, and again when the supplier’s software converts your already-reduced file. The print usually comes out flatter than if you had left it alone.
How to keep bright colors on custom merch
- 1Find out which colors are at riskPut the image through the print color checker. Switch between “On screen” and “In print” and tick “Show only what changes” to see exactly which parts move.
- 2Choose colors ink can reachWarm colors survive best. If a design depends on one strong color, a red, orange or deep blue keeps more of its punch than a neon green or violet.
- 3Use contrast instead of glowBrightness in print comes from light next to dark. A bright color against black or deep navy looks brighter than the same color on its own.
- 4Tone down what is markedLower vibrance before saturation, and stop when the two views nearly match. You choose how it looks instead of leaving it to the printer.
For AI images, which are often full of neon, the longer version with prompts that print well is in why AI art prints duller than your screen.
The product matters too
- Posters and paper hold the most color. A matte poster is a little softer than a glossy one.
- Shirts and hoodies reach the fewest colors, because cotton drinks the ink in. On a dark hoodie the colors sit on a white underbase and look brighter than they would on bare fabric, but still not like a screen.
- Mugs and stickers sit in between. A glossy mug keeps colors well.
- Embroidery uses thread colors, not ink, from a fixed set. Small color differences in the file disappear.
Whatever you print on, the only exact answer is a real one. Print on demand has no minimum, so order one T-shirt and look at it in daylight before you order more or list it for sale.
Questions people ask
Should I use RGB or CMYK for print on demand?
RGB, in the sRGB color profile. Print-on-demand suppliers such as Printful ask for sRGB files and convert them on their own printers. Converting to CMYK yourself first usually makes the print flatter.
Why do my colors look different when printed?
A screen makes color with light and can show purer greens, blues and violets than ink can mix. The printer replaces each of those with the nearest color it has, which is duller and often a little darker. Reds, oranges, earth tones and grays change much less.
Which colors print best on shirts?
Warm colors, deep blues, earth tones, black and white keep closest to what you see. Neon green, electric blue, hot pink and bright violet lose the most. Strong contrast between light and dark makes a shirt print look brighter than any single color can.
What is Display P3, and does it matter for printing?
Display P3 is a wider RGB color space used by recent Apple screens and cameras. A file saved in it can look different once a supplier reads it as sRGB. Convert it to sRGB before uploading so the colors are read the way you saw them.
