CMYK Gamut Check
Scan a PDF for highly-saturated RGB colors that fall outside CMYK gamut and will not print accurately on a 4-color press. Audit before sending to print.
1. Upload your file
How does the CMYK Gamut Check work?
Walk a PDF's page content streams, collect every RGB fill / stroke color, and flag the ones that fall outside the CMYK printable gamut. The check uses a heuristic — colors are flagged if they're highly saturated AND in the bright/pure region of one or more channels (e.g. pure cyan #00FFFF, pure red #FF0000, neon greens). These often look fine on screen but print as muted or shifted on a 4-color press. The output is a plain-text report listing each problematic color, how often it appears, and the reason. This is a heuristic — for an authoritative check, use Acrobat Pro's Output Preview + your destination ICC profile, but this tool catches 80% of the common issues for free.
🔒 Security & Privacy
All processing happens on your device. Your files never leave your browser, never touch our servers, and are not stored anywhere. Close the tab and the file is gone.
📱 Use it on any device
Works in any modern browser — Mac, Windows, Linux, iPhone, Android, and tablets. No installation, no app to download. Just open the page and start.
⚡ Quick & easy
Drag, drop, click. Most files process in seconds, not minutes. No watermarks added to your output, no per-day limits, and the tool always shows the result before asking you to download.
🎁 Always free, no signup
Free to use, every time. No account creation, no email required, no “trial” that converts to a paid plan. We make money from ads so you don’t have to pay.