用强有力的密码保护和加密保护你的PDF。
在不影响画质的情况下减少文件大小。
You want a PDF that looks great but doesn’t take forever to download or exceed email limits. You don’t have to choose between quality and file size. Our AI‑powered tool finds the sweet spot: smart compression reduces file size by 50‑70% while preserving sharp text and clear images. Choose presets for web, email, office print, or professional print. Perfect for reports, brochures, scanned documents, and any PDF that needs to be both high‑quality and compact. Free trial, no signup required.
Did you know? A 20 MB PDF can often be reduced to under 5 MB with our balanced optimisation – perfect for email or web upload – while remaining perfectly readable on screen.
PDF over 25 MB bounces. Our optimisation keeps you under limits.
Large files frustrate recipients. Shrink without losing clarity.
Job portals, courts, and submission systems often cap file size.
Smaller PDFs save cloud and device space.
Bonus – print vs screen: A file optimised for screen (150 DPI) might print poorly. Our Office Print preset (200 DPI) fits both uses.
Upload your PDF – The tool analyses resolution, image count, and metadata.
Select optimisation profile – Web (72 DPI, smallest), Email (150 DPI, balanced), Office Print (200 DPI), or Professional Print (300 DPI).
Adjust advanced settings (optional) – JPEG quality, downsampling, metadata removal.
Apply optimisation – The tool downscales images, compresses, and removes redundant data. Preview the result.
Download the optimised PDF – Perfect balance of quality and size.
Pro Tip: For documents with a mix of text and photos, use “Office Print” – it keeps images readable while shrinking total size.
These techniques are automatically applied based on your chosen profile.
Each profile balances quality and file size differently:
You can also customise each setting manually.
Here is what you can expect from a typical 10‑page PDF (mixed text and images):
Tip: Test a single page first to see which profile meets your needs, then apply to the whole document.
Yes. Our smart compression removes redundant metadata, optimises images (downsampling to 150‑200 DPI), and uses efficient JPEG2000 compression. For many documents, you can reduce size by 50‑70% with no visible quality loss.
Higher quality (300 DPI, lossless images) means larger files. Lower quality (72 DPI, heavy compression) gives smaller files but blurry prints. Our tool lets you choose a preset – Web, Email, Office Print, or Professional Print – that matches your need.
For text‑heavy PDFs, 60‑80% reduction is common without noticeable loss. For image‑heavy files, 40‑60% reduction still preserves good detail. Our preview shows you the result before downloading.
Yes. Choose from: Web (72‑96 DPI, high compression), Email (150 DPI, medium compression), Office Print (200 DPI, balanced), or Professional Print (300 DPI, low compression). You can also customise DPI and JPEG quality.
We downsample images, remove metadata, compress with JPEG2000/Flate, subset fonts, flatten annotations, and discard unused objects. All without affecting text or layout.
Yes. TLS 1.3 encryption, auto‑deletion within 24 hours. An offline desktop version is available for maximum privacy.
The online tool processes one file at a time. For batch optimization, our desktop application (paid) handles entire folders with the same settings.
No. Text remains searchable and selectable – we only change images and metadata. Your text layer stays intact.
Upload your PDF and let AI find the optimal combination of quality and file size – free trial, no signup.
增强PDF通过调整分辨率、锐化文本边缘以及增加前景和背景元素之间的对比度来提高视觉清晰度。此过程对于扫描文档、模糊文本或褪色文件特别有用。
多种因素可能降低PDF文档的可读性。低分辨率扫描、过度压缩、不正确的导出设置和相机拍摄的文档都可能导致模糊或降低对比度。
现代PDF增强工具应用多种处理技术来提高可读性。
PDF增强算法通过分析像素密度和灰度分布来工作。对比度调整增加了文本和背景之间的差异,而锐化滤波器重建模糊边缘。当与OCR准备结合时,增强显著提高了机器可读性。
在PDF增强指南中探索完整的工具集合。