---
title: "CMYK (CMYK colour mode): meaning and marketplace rules | Herofab"
description: "The colour mode of printing, built from cyan, magenta, yellow and black ink. Product images for the web use RGB instead."
url: https://herofab.app/glossary/cmyk
language: en
updated: 2026-10-07
---

# CMYK

The colour mode of printing, built from cyan, magenta, yellow and black ink. Product images for the web use RGB instead.

Also called **CMYK colour mode** · **four-colour process** · **print colour mode**

![The same model with the bomber jacket in navy blue](https://herofab.app/img/ex/bomber-navy-1100.webp)

Made with Herofab · Colour variants

Screens make colour by adding red, green and blue light; presses make it by laying four inks on paper. A file saved in CMYK describes ink, and a browser that expects light has to convert it. The result is often dull or shifted colour, and some systems cannot read such a file at all.

CMYK files usually reach a webshop from print work: a catalogue, a packaging design, an agency export. Several marketplaces state that they do not accept the mode, or warn that it causes errors, and ask for RGB or the sRGB profile. A few specifications written for print and retail suppliers still accept both.

Converting to RGB in an image editor before upload solves the problem, and it is worth comparing the colours afterwards, since strong blues and greens change most. Photos from a phone or camera are RGB from the start, as are images produced for the web.

## CMYK, answered.

**How do I know if a product image is CMYK or RGB?**

An image editor shows the colour mode in its mode menu or image information, and many file viewers list it among the file's details as colour space or colour model. A warning sign that needs no editor is a picture that looks right in a design program and dull, shifted or inverted in a browser.

**Does converting CMYK to RGB reduce image quality?**

Not the sharpness: the pixels stay where they are and only their colour values are recalculated. What can change is the colour itself, since the two modes do not cover the same range, so the result should be compared with the product. Converting to the sRGB profile and embedding it in the file gives browsers a description they read reliably.

## What marketplaces say about it.

Updated 25 September 2026

- **OTTO:** JPG or PNG, RGB colour space (CMYK is not accepted) [Official page](https://www.otto.market/_Resources/Persistent/4/0/f/9/40f93e8e8315a91f7c8dab0e2bf4cf14057d1279/18012024_Onboarding-Guide.pdf)
- **Zalando:** JPG/JPEG only, up to 20 MB, sRGB colour mode [Official page](https://partner.zalando.com/university/article/zalando-image-guidelines)
- **Hood.de:** GIF, PNG or JPG; other formats such as BMP cannot be processed, and files saved in CMYK instead of RGB can cause errors [Official page](https://www.hood.de/tips/1530/standards-fuer-produktbilder.htm)
- **Best Buy Canada:** Cropped close to the product on a white background; EPS, TIFF, JPEG or PSD, in that order of preference; RGB or CMYK [Official page](https://partners.bestbuy.com/-/digital-assets-product-shot-guides-ca)

Related

[Colour variants](https://herofab.app/tools/color-variants) · [Product studio](https://herofab.app/tools/product-photography) · [sRGB colour space](https://herofab.app/glossary/srgb) · [Colour variant images](https://herofab.app/glossary/colour-variant-images) · [All terms](https://herofab.app/glossary/)