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Adjust Colors

A full color grading toolkit for PDFs. Adjust eight independent parameters -- brightness, contrast, saturation, hue shift, temperature, tint, gamma, and sepia -- with a live preview that updates as you move each slider.

How It Works

  1. Upload your PDF file.
  2. The editor opens showing a preview of the first page and a color settings panel.
  3. Move the sliders to adjust each color parameter. The preview updates in real time.
  4. Click Reset to restore all sliders to their default positions.
  5. Click Apply to process all pages and download the adjusted PDF.

Options

  • Brightness -- Lighten or darken the entire page (-100 to +100).
  • Contrast -- Increase or decrease the difference between light and dark areas (-100 to +100).
  • Saturation -- Boost or reduce color intensity (-100 to +100). Setting to -100 produces a grayscale result.
  • Hue Shift -- Rotate the color wheel to shift all colors uniformly.
  • Temperature -- Shift colors warmer (yellow/orange) or cooler (blue).
  • Tint -- Add a green or magenta cast.
  • Gamma -- Adjust midtone brightness using a gamma curve. Values below 1.0 darken midtones; values above 1.0 lighten them.
  • Sepia -- Apply a classic sepia tone effect. Higher values produce a stronger brown tint.

Features

  • Eight independently adjustable color parameters
  • Live preview that responds immediately to slider changes
  • Reset button to quickly return to defaults
  • Processes all pages in the document
  • Works with any PDF content (text, images, graphics)

Use Cases

  • Brightening a dark scan or correcting overexposed pages
  • Desaturating a colorful document to reduce ink usage before printing
  • Applying a sepia tone to create an antique look for certificates or awards
  • Correcting color temperature on photos embedded in a PDF
  • Boosting contrast on faded or low-quality scanned documents

Tips

  • For a quick grayscale conversion, drag the saturation slider all the way to -100.
  • The gamma slider is particularly useful for improving readability of scanned documents where midtones are too dark or too light.
  • Like the other image-effect tools, this rasterizes each page. The output will be image-based, so text will not be selectable.

Dual-licensed under AGPL-3.0 and Commercial License.