Color in PDF is not as simple as "RGB or CMYK." Every color value is meaningless without a profile telling viewers what those numbers should look like. Get profiles right and your file looks the same on a designer's monitor and a printer's press. Skip them and every device interprets differently.
Color Spaces You'll Meet
| Space | Used by | Gamut | When to use |
|---|---|---|---|
| sRGB | Web, most monitors | Smallest of the common RGB | Screen-only PDFs, web delivery |
| Display P3 / Adobe RGB | Wide-gamut monitors | ~25-30% wider than sRGB | Photo portfolios for HDR screens |
| CMYK (FOGRA, GRACoL, SWOP) | Commercial press | Smaller than sRGB in cyan/green | Print production |
| Spot / Separation | Brand inks (Pantone, HKS) | Defined per ink | Logos, packaging, special finishes |
| DeviceGray | B&W print | Grayscale only | Books, draft prints |
| Lab (PCS) | Internal connection space | Larger than any device | Profile-to-profile conversion |
How Profiles Travel With a PDF
Each color value in a PDF references a color space object. That object can be a device space (DeviceRGB, DeviceCMYK) with no profile — uncalibrated, unsafe for print — or an ICC-based space that points to an embedded ICC profile stream. Authoring tools should always tag content with proper ICC profiles. PDF/A-2b and PDF/X-4 require it.
The document-level output intent declares the target reproduction condition. When a PDF says "I'm written against FOGRA39 coated press," every downstream RIP knows what to do when it converts your RGB or CMYK content to the actual press condition.
Common Pitfalls
- Vibrant blues turning purple in print: sRGB blue is outside CMYK gamut. Soft-proof before printing.
- Black text becoming "rich black": exporting "100% K" text as CMYK (60,40,40,100) makes registration sensitive. Force pure K=100 for body text.
- Logos shifting between RGB and CMYK pages: include the same vector logo defined in both spaces or rely on ICC conversion at output.
- Missing output intent: printer can't predict color and rejects PDF/X validation.
Quick Workflow
- Calibrate your monitor and use a known profile (sRGB or Display P3).
- Set authoring document color spaces to match the target — RGB for screen, the press CMYK profile for print.
- Export to PDF/X-4 with the correct output intent for print work, PDF/A-2b with sRGB output intent for archives.
- Soft-proof in the authoring tool using the target press profile.
- Ask the print shop which output intent they expect.
Render PDFs as Images for Proofing
Export PDF pages to PNG or JPEG to preview color in-browser.
PDF to Image →