PDF Compression Blog.
Technical articles, document scanning guides, and portal rejection fixes written by Zcompressor engineering.
Common document upload rejection reasons & how to fix them.
Document rejections during government scholarship and exam registrations can cost candidates their application eligibility. Here are the top 7 failure modes and how to prevent them.
How to scan documents for government portals.
Avoid document upload rejections by using optimal scanner resolution (150–200 DPI), grayscale color modes, and proper cropping before compressing your PDFs.
KB vs KiB file size: why government portals reject 300 KB PDFs.
Ever compressed a file to exactly 300.0 KB according to Windows, only for a portal like UPSC or NSP to reject it for exceeding 300 KB? Here is the binary vs decimal calculation discrepancy.
PDF compression: lossy vs. lossless algorithms.
A technical breakdown of how PDF stream encoding, Flate/Deflate algorithms, and lossy image DCT downsampling work together to reduce document file sizes.
Why is my PDF still too large after compression?
If your PDF file barely changes size when compressed, embedded fonts, pre-compressed JPEG streams, or scanner color depths are causing the bottleneck. Here is how to fix it.