RGB or CMYK for Photo Printing? What Actually Matters

Created by: PrintForFun. Reviewed and updated by the KT Colour team, October 2026.

The short answer: send photos as RGB, in sRGB, as a JPEG. Photo printers and photographic paper work from RGB files, and converting a photo to CMYK yourself usually makes it worse. CMYK matters for graphic design headed to a commercial press: logos, flyers, cards with solid brand colours. In both cases the screen will never match the print exactly, because a screen glows and paper reflects, so preview your colours before you order and keep an eye on bright blues and greens.

RGB in one paragraph

RGB stands for red, green and blue, the three colours of light that every screen mixes to show you a picture. It is an additive model: add all three at full strength and you get white, add none and you get black. Every phone camera, every monitor and every photo-editing app works in RGB, and it can describe more colours than any printer can put on paper, especially bright, saturated ones.

CMYK in one paragraph

CMYK stands for cyan, magenta, yellow and key, which is black. These are inks, and ink works the opposite way: it subtracts light from white paper. Mix all three coloured inks and you get a muddy dark brown, which is why black ink is added for a true black. CMYK is the language of offset presses and most office printers. It cannot reproduce the most vivid RGB colours, so those get pulled back to the nearest ink colour when a file is converted.

Why the print does not match the screen

Three things are usually going on at once:

• Your screen is too bright. Most phones and laptops display at a brightness far above what a print can reflect, so every print looks a little darker than the screen. Turn the screen to about half brightness when judging a photo for print.
• Colour gamut. Electric blues, neon greens and hot pinks exist on screen but not in ink or photographic dye. They print as the closest colour available, which is less intense.
• Paper and finish. A lustre photo paper, a matte cotton rag and a glossy canvas each show the same file differently. Matte papers in particular look softer and less contrasty than the screen.

What to send for photos

Leave the photo in RGB. Our photo prints are made on Fujifilm photographic paper and our posters, canvas and fine art prints on calibrated inkjet printers with custom paper profiles. All of them expect an RGB file and do the conversion to the printer's own colour space with a profile built for that paper. If you convert to CMYK first, you throw away colours the printer could have reproduced and add a second conversion on top.

If your camera or editor offers a colour space, choose sRGB rather than Adobe RGB or Display P3 unless you know the lab handles them. Files in a wide colour space that are not tagged correctly print dull.

What to send for designs

A card, a flyer or a logo going to a commercial press should be set up in CMYK from the start, so what you see while designing is already limited to what ink can do. For our own cards and namecards either mode is fine; we check every file before printing and tell you if a colour will shift noticeably.

Previewing in Photoshop before you order

Go to View > Proof Colors (Ctrl or Cmd + Y). Photoshop shows the image as it would look after conversion to the proof setup, which by default is a standard CMYK press. Colours that dull down noticeably are the ones to watch. You can also turn on View > Gamut Warning, which greys out every pixel that falls outside the printable range.

If something has shifted, a Selective Color adjustment layer lets you nudge just the reds, blues or greens without touching the rest of the photo. Pull the saturation of a neon colour back a little and it will print closer to what you see.

Only if a press printer has asked for CMYK, convert the final copy with Image > Mode > CMYK Color and keep the RGB original. In Illustrator the setting is File > Document Color Mode, and Illustrator defaults to CMYK for print documents.