What does Adjust Colors do?

It lets you tweak brightness, contrast, gamma, and sepia tone on every page of your PDF. Changes are previewed live and applied to the full document.

Is my PDF uploaded to a server?

No. All processing happens in your browser. Your file stays on your device.

What is gamma correction?

Gamma adjusts midtone brightness without affecting the very darkest or lightest areas. A value below 1.0 darkens midtones, above 1.0 lightens them. Default is 1.0 (no change).

Can I reset all adjustments?

Yes. A reset button returns brightness, contrast, gamma, and sepia to their defaults.

Can I preview before applying?

Yes. The preview updates in real time as you move the sliders.

Is the output rasterized?

Yes. Pages are rendered at 2x resolution (144 DPI) and rebuilt as images.

Does it work with password-protected PDFs?

Yes. Enter the password when prompted. Decryption runs locally.

Can I adjust multiple PDFs at once?

Yes. Batch mode applies the same adjustments to all files.

Điều chỉnh màu sắc

Tinh chỉnh độ sáng, độ tương phản, độ bão hòa và nhiều thông số khác.

1. Select PDF

Select a PDF file from your device. All processing happens locally in your browser.

2. Adjust settings

Tune brightness, contrast, saturation, gamma, and sepia with real-time preview.

3. Download

Get your color-adjusted PDF instantly.

About Adjust Colors

Fine-Tune Your PDF’s Appearance

Adjust Colors gives you four controls: brightness (-100 to +100), contrast (-100 to +100), gamma correction (0.1 to 5.0), and a sepia tone toggle. Move the sliders, see the result in real time on your actual pages, then apply when it looks right.

The tool renders each page to canvas, applies the adjustments pixel by pixel, and rebuilds the PDF at 2x resolution. Everything happens in your browser — your file never leaves your device.

When to Adjust PDF Colors

Color adjustments fix problems and improve readability. Different situations call for different settings.

Fix Scanned Documents

Scanned pages often come out too dark, too light, or washed out. Adjust brightness and contrast to make text sharp and readable.

Print Preparation

Colors on screen don’t always match print. Tweak brightness and contrast so printed output matches what you expect.

Photo-Heavy PDFs

PDFs with photographs benefit from gamma correction and contrast adjustments. Fine-tune images without opening a separate editor.

Sepia Effect

Apply a warm sepia tone for a vintage or aged-paper look. Works well on documents meant for display or design projects.

What Each Slider Does

Brightness shifts all pixels lighter or darker. Contrast increases or decreases the difference between light and dark areas. Gamma correction adjusts midtone brightness without blowing out highlights or crushing shadows — useful for scanned documents where the overall lightness is off but the extremes are fine.

Sepia applies a warm brownish tone across the entire document. All four adjustments stack: you can boost contrast, darken slightly, and apply sepia in one pass. A reset button returns everything to defaults.

How It Compares

PDF color adjustment tools are uncommon. Most require image editing software and a round-trip through export/reimport.

Tính năng	OxygenPDF	Adobe Acrobat	iLovePDF
Brightness adjustment		Preflight
Contrast adjustment		Preflight
Gamma correction		Preflight
Sepia tone
Live preview
Batch processing
No file upload required		Desktop only
Free to use

Nothing Leaves Your Machine

Color adjustments run entirely in your browser. Pages are rendered, processed, and rebuilt locally. The adjusted PDF downloads straight to your machine.