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Brightness
Contrast

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Brightness and contrast image editor

Adjust brightness and contrast online with dual sliders. Use this picture brightener and image contrast editor to lighten or increase contrast, then download PNG.

What are brightness and contrast adjustments?

Brightness shifts every pixel lighter or darker by a uniform amount, useful when a photo is underexposed or too bright. Contrast stretches tones away from or toward mid-gray so shadows and highlights separate more or less. This page works as a combined brightness and contrast image editor: contrast is computed around 128 per RGB channel, then the brightness offset is added. Upload, move both sliders, preview beside the input, and download PNG in your browser.

Brightness and contrast features

Tune lightness and image contrast together in the browser.

  1. Dual sliders: Brightness and contrast from −100 to +100 on one page.
  2. Live preview: Output refreshes as you drag either control.
  3. Non-destructive source: Every preview recomputes from the original upload.
  4. Side-by-side panels: Compare input and adjusted images before download.
  5. PNG download: Save as brightness-contrast-image.png.
  6. Client-side only: No server upload or account.

How to adjust brightness and contrast

Steps to brighten pictures and increase contrast online.

  1. Upload your image: Drop or click in the input panel (15 MB max).
  2. Set brightness: Raise to lighten shadows; lower to darken an overexposed shot.
  3. Set contrast: Increase for punch; decrease for a softer, flatter look.
  4. Download PNG: Save when the combined adjustment looks balanced.

Tips for brightness and contrast

Balanced brightness and contrast without clipping.

  1. Small moves first: Try ±10–20 on each slider before larger corrections.
  2. Contrast after brightness: Set overall lightness, then add contrast for edge definition.
  3. Watch clipped whites: High brightness plus high contrast can blow out highlights.
  4. Use dedicated tools for one knob: /change-image-brightness or /change-image-contrast when you only need one.
  5. Pair with gamma: /adjust-image-gamma when you want a non-linear midtone curve instead of linear brightness.
  6. Export PNG: Avoid extra JPEG compression after tone edits.

When to use brightness and contrast

Typical uses for combined tone adjustment.

  1. Underexposed photos: Lift brightness then add contrast for readable detail.
  2. Flat phone shots: Boost contrast when images look hazy or washed out.
  3. Scanned documents: Darken yellowed paper or sharpen text separation.
  4. Social graphics: Quick punch before posting without opening an editor.
  5. Product thumbnails: Match exposure across a batch of SKU photos.
  6. Screenshot cleanup: Balance UI captures that look too dim or gray.

Why use this brightness and contrast tool

Benefits of combined tone controls.

  1. One workflow: Both adjustments on a single page—no tab switching.
  2. Private: Images stay on your device.
  3. Predictable range: Same −100 to +100 scale as the standalone brightness and contrast tools.
  4. Free: Unlimited previews and downloads.
  5. No install: Works in modern browsers with Canvas 2D.
  6. Alpha preserved: Transparency on PNG uploads is left unchanged.

Technical details

How brightness and contrast are applied.

  1. Brightness: Per channel: value + round((brightness / 100) × 255), clamped 0–255.
  2. Contrast: factor = (259 × (contrast + 255)) / (255 × (259 − contrast)); applied around 128 first.
  3. Alpha channel: Unchanged from source.
  4. Input limits: 15 MB; longest edge 8192 px.
  5. Rendering: Canvas 2D getImageData / putImageData.
  6. Browser support: Chromium, Firefox, Safari with Canvas 2D.

Frequently Asked Questions

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