Why is my PDF text gray?

Cause 1: the text colour is grey

Some documents simply are not black. Web templates and design tools often set body text to dark grey such as #333, or to a lighter grey such as #666 or #999, because it looks softer on a bright screen. The PDF then contains that exact grey.

How much it matters is measurable. Against white paper, the contrast ratio of #333333 is about 12.6 to 1, #666666 is about 5.7 to 1, #767676 is about 4.5 to 1, and #999999 is about 2.9 to 1. The widely used accessibility guideline asks for at least 4.5 to 1 for normal text, so the lighter greys already fail on screen, and paper is less forgiving than a screen.

Cause 2: the strokes are too thin

Text in a light or thin typeface, or at a small size, has strokes narrower than a pixel or a printed dot. A screen blends them with the background using anti-aliasing, and the result reads as grey. A printer cannot blend: it lays down a thin line of toner or ink, which still looks grey at reading distance.

The colour value can be pure black and the text still looks grey. That is why zooming in on a letter helps: a thin stroke shows as a pale line rather than a solid shape.

Cause 3: it prints grey but is black on screen

• A toner-save, economy or draft setting in the printer or its driver, which prints everything lighter on purpose.
• A low print-quality setting, or the wrong paper type for the ink, which lets ink spread or lays down less of it.
• On some inkjet drivers, text that is black in RGB is printed using a mix of inks rather than the black cartridge, which can look dull or slightly tinted. Choosing a black-only or grayscale print option often prints it in pure black ink. The names of these options vary between drivers.

How to tell which one you have

1. Zoom to 400% on a letter. A pale, even grey shape means Cause 1. A solid dark shape that is very thin means Cause 2.
2. If it looks black on screen and prints grey, check Cause 3 first: print a different document you know prints well. If that is also pale, the printer is the problem.
3. If only this document is pale, the file is the problem, and it is Cause 1 or 2.

What to change

• Grey colour (Cause 1): use Darken PDF, which rewrites the text colour of text and vector pages towards black and keeps the text selectable, or re-export the document with black text.
• Thin strokes (Cause 2): the Thicken thin text option gives each glyph a hairline outline. It is on by default for text pages and can be switched off under Advanced settings.
• Printer (Cause 3): turn off economy and draft modes, raise the print quality, and match the paper type setting to the paper. See how to make a PDF print clearly.