Adjust gamma correction for multiple images at once to brighten or darken midtones.
Select multiple images to adjust gamma in batch
Upload multiple images to adjust gamma in batch
The Bulk Adjust Gamma tool enables you to apply gamma correction to multiple images simultaneously, brightening or darkening midtones while preserving highlights and shadows. This powerful batch processing feature is essential for correcting exposure in photo collections, preparing images for different display devices, normalizing image sets for consistent appearance, and enhancing details in underexposed or overexposed batches.
Gamma correction is a non-linear adjustment that primarily affects the middle tones of your images. Unlike simple brightness adjustments that affect all pixels equally, gamma correction uses a power function to reshape the tonal curve, creating more natural and pleasing results. Values below 1.0 darken midtones (useful for overexposed images), while values above 1.0 brighten midtones (useful for underexposed images). The adjustable gamma control allows you to apply consistent correction across your entire image batch.
Bulk gamma adjustment saves significant time when working with multiple images that need the same tonal correction. Instead of processing each image separately and trying to remember or replicate the exact gamma value, you can apply consistent correction to dozens or hundreds of images in a single batch operation. This is invaluable for photo series from the same shoot, scanned image collections, screenshots from the same source, and any workflow requiring uniform tonal adjustment across multiple images. The batch approach ensures every image receives identical gamma correction for professional consistency.
Gamma correction is a non-linear operation that adjusts the midtones of an image using a power function, while brightness adjustment adds or subtracts the same value from all pixels uniformly. Gamma correction primarily affects the middle tones without significantly impacting the darkest shadows or brightest highlights, creating more natural-looking adjustments. A gamma value of 1.0 leaves the image unchanged, values below 1.0 (0.1-0.99) darken the midtones making images appear darker overall, and values above 1.0 (1.01-3.0) brighten the midtones making images appear lighter. This makes gamma ideal for correcting images that look too dark or too light in the middle tonal range while preserving detail in shadows and highlights.
Start with the default gamma of 1.0 and adjust based on your images' needs. For underexposed images (too dark), increase gamma to 1.2-1.8 to brighten midtones and reveal hidden details. For overexposed images (too bright), decrease gamma to 0.6-0.9 to darken midtones and restore depth. For subtle corrections, make small adjustments of 0.1-0.2, while dramatic problems may require larger changes. The key is ensuring all images in your batch have similar exposure issues, as the same gamma value will be applied to all. Process a small test batch first to find the optimal value before processing your entire collection.
While the same gamma value is applied uniformly, the visual results will vary based on each image's original tonal distribution and content. Images with predominantly midtone values will show more dramatic changes, while images with mostly shadows or highlights will show subtler effects. Images that are already properly exposed may become over-corrected, while images with severe exposure problems may show limited improvement. For best results, group images with similar exposure characteristics together and process them as separate batches. This ensures more consistent and predictable results across each batch while allowing you to tailor the gamma value to each group's specific needs.
Gamma adjustment works best for moderate exposure issues and cannot fully recover severely underexposed (pure black areas) or overexposed (blown-out highlights) images, whether processing individually or in bulk. When image data is completely black, there's no hidden information to reveal, and when highlights are blown out to pure white, that detail is permanently lost. Gamma adjustment can improve images with slightly muddy midtones or flat-looking photos, but severe exposure problems are beyond repair. For mixed batches containing both recoverable and severely damaged images, consider sorting them first and processing only the recoverable ones to avoid wasting processing time on images that won't benefit.
Bulk gamma adjustment has many professional applications: correcting photo series from indoor shoots with consistent underexposure, normalizing scanned image collections for uniform appearance, preparing images for specific display devices (web vs print have different gamma requirements), enhancing product photography batches for e-commerce with consistent tonal balance, correcting screenshots or screen captures from the same source, preparing images for video production where consistent tonality is crucial, and adjusting real estate photography collections for uniform brightness. Any workflow requiring consistent tonal correction across multiple images benefits from batch gamma processing, ensuring professional results and significant time savings.
You can adjust unlimited images in a single batch, though practical limits depend on your device's memory and browser capacity. Gamma correction processes each pixel using a mathematical power function, which is computationally intensive. Most devices can handle 30-100 images without issues, and modern computers with sufficient RAM can process several hundred. The tool processes images sequentially to prevent memory overload while maintaining reasonable processing speed. Larger images (high resolution) take longer to process than smaller ones due to the greater number of pixels requiring calculation. Monitor the progress indicator to track batch completion.
Gamma adjustment preserves image resolution and dimensions but may introduce subtle banding in images with smooth gradients if extreme values are used. Moderate gamma adjustments (0.5-2.0) maintain excellent quality, while extreme adjustments (below 0.3 or above 2.5) can cause visible posterization in smooth areas like skies or subtle shadows. The tool outputs images in PNG format for lossless quality, which typically results in larger file sizes than JPEG but ensures no additional compression artifacts. If file size is a concern for web use, consider converting the adjusted images to JPEG afterward using an image compression tool. The original image data and metadata are preserved during processing.
After processing completes, you have two download options: download each adjusted image individually by clicking the download button on each preview (useful when you only need select images from the batch), or download all adjusted images at once as a ZIP archive by clicking the "Download ZIP" button. The ZIP option is highly recommended for large batches as it packages all images into a single compressed file with organized naming (originalname_gamma_adjusted.png), making it easy to manage and share your entire processed batch. All images are saved in PNG format to preserve quality and transparency if present.
Yes, your images are completely private and secure. All gamma correction processing happens entirely in your browser using client-side JavaScript and the HTML5 Canvas API. Your images are never uploaded to any server, transmitted over the internet, or stored anywhere except temporarily in your browser's memory during processing. Once you close the page or refresh, all image data is immediately cleared from memory. You have complete control over your files throughout the entire batch gamma adjustment process, ensuring complete privacy for your photos, projects, and sensitive images.
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