A gray background on a PDF page is usually one of three things: it was designed that way intentionally, it's a viewer display setting, or it came from the scanning process. Each has a different fix, and it's worth spending ten seconds ruling out the viewer issue before doing anything else.
Check the Viewer First
Adobe Reader has a setting called Page Background Color that can make pages appear with a tinted background โ this is meant to reduce eye strain for people who find pure white too bright. If someone adjusted this setting, every PDF they open will look gray even though the files themselves are white. Go to Edit โ Preferences โ Accessibility and check whether "Replace Document Colors" or a custom background color is turned on. Turning it off restores the original page colors.
Some browsers also render PDFs with a slight gray tint by default. If the background looks gray in Chrome but white when you download and open the same file in Adobe Reader, it's purely a display setting โ the PDF itself is fine.
Gray Background Built Into the Document
If the background appears gray in every viewer you try, it's part of the document itself. This can happen a few different ways. Some documents are deliberately designed with a gray background โ legal forms, government documents, and certain templates use a background shade to distinguish the form from surrounding white space. Others end up with gray pages because the page background color was set in the source application (Word, InDesign, etc.) before export.
Word documents with a gray page color export to PDF with that color preserved. If the original document had a colored background set under Design โ Page Color, the PDF will reflect that. Going back to Word, removing the page color (set it to No Color), and re-exporting fixes it at the source.
For PDFs you've received and can't re-export from source, a PDF Editor can sometimes remove background elements โ though this depends on how the background was implemented. If it's a filled rectangle object covering the page, it can be deleted. If it's a page-level color setting baked into the PDF structure, it's harder to remove without specialized tools.
Scanned Documents With Gray Backgrounds
Scanned PDFs often have gray or off-white backgrounds instead of pure white because paper isn't perfectly white and scanners pick up that variation. The background shade depends on the paper quality, the scanner's exposure settings, and whether any image processing was applied during scanning.
There are two approaches to fixing this. The first is adjusting the scanner settings for future scans: increasing contrast, enabling automatic background removal if the scanner supports it, or scanning in black-and-white mode instead of grayscale โ black-and-white scanning forces everything to pure black or pure white and eliminates gray tones entirely.
For existing scanned PDFs with gray backgrounds, some PDF optimization tools include a "clean background" or "whiten background" option that boosts contrast and pushes near-white pixels to pure white. The result isn't always perfect โ if the text itself has soft edges from the scan, over-brightening can make it look harsh โ but for standard printed text on decent paper, it usually improves readability significantly.
Gray Boxes Around Specific Elements
Sometimes the gray background isn't the whole page but appears around specific elements โ text fields in a form, table cells, or specific content blocks. Form fields in PDFs often have a gray background by default to visually indicate where to type. This is intentional design and is generally fine to leave as-is. If it's table shading or cell backgrounds from a Word or Excel source, those came from the original formatting and would need to be removed at the source level before re-exporting.