How Grayscale Conversion Reduces PDF File Size
Converting a colour PDF to grayscale reduces file size by 30–50%. Explained with tips.
Colour images in PDFs store three channels (R, G, B) per pixel. Grayscale stores one. Converting to grayscale reduces image data by approximately 66%, resulting in smaller files.
Expected Reduction
Text-only PDFs: minimal size change (text colour data is small). Image-heavy PDFs: 30–60% size reduction. Mixed PDFs: 20–40% reduction.
Combine with Compression
For maximum size reduction: convert to grayscale first with FixMyPDF, then compress the result with FixMyPDF compress. Typical combined reduction: 60–80%.
When to Use Grayscale
Reports, documents, and forms where colour is decorative rather than informational. Archival copies where file size matters. Printing on black-and-white printers.
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