# Image Normalize Normalize image histogram to enhance contrast by stretching the intensity range > Canonical page: https://elysiatools.com/en/tools/image-normalize - **Category:** Design - **Keywords:** image, normalize, histogram, contrast, enhance, stretch, intensity, equalization ## Overview Image Normalize is a professional-grade utility designed to enhance image contrast by stretching the pixel intensity range across the full histogram spectrum. By remapping the darkest and brightest values, this tool effectively clarifies washed-out photos and improves visual depth without requiring complex editing software. ## Inputs - **Image File** (file): Upload any image file (JPEG, PNG, WebP, GIF, BMP, TIFF) to enhance contrast through histogram normalization - **Auto Contrast** (checkbox): Automatically enhance contrast using 1% and 99% percentiles (recommended for most images) - **Lower Percentile** (range): Percentage of darkest pixels to ignore (0.1% - 10%). Lower values preserve more shadow detail - **Upper Percentile** (range): Percentage of brightest pixels to ignore (90% - 99.9%). Higher values preserve more highlight detail - **Output Format** (select): Choose output format or keep original. PNG recommended for maximum quality - **Quality (1-100)** (number): Output quality for lossy formats (JPEG, WebP). Higher = better quality but larger file size ## When to use - Correcting images that appear flat, dull, or lack sufficient contrast. - Standardizing visual consistency across a batch of images with varying lighting conditions. - Preparing images for analysis by maximizing the dynamic range of pixel intensities. ## How it works - Upload your image file (JPEG, PNG, WebP, GIF, BMP, or TIFF). - Enable 'Auto Contrast' for a standard enhancement or manually adjust the lower and upper percentiles to define your intensity range. - Select your preferred output format and quality settings. - Process the image to instantly download the contrast-enhanced version. ## Use cases - Restoring old or faded scanned documents to make text more legible. - Enhancing low-contrast photography taken in overcast or hazy conditions. - Optimizing medical or scientific imagery for better feature visibility. ## Frequently asked questions ### What does histogram normalization do? It stretches the intensity range of an image so that the darkest pixels become black and the brightest pixels become white, which significantly improves overall contrast. ### How do the percentile sliders work? The lower percentile ignores the darkest pixels, while the upper percentile ignores the brightest. This helps prevent extreme noise or outliers from skewing the contrast adjustment. ### Can I change the file format? Yes, you can convert your image to JPEG, PNG, or WebP, or choose to keep the original file format. ### Is there a limit to the file size? Yes, the tool supports image files up to 20 MB. ### Does this tool reduce image quality? The tool uses high-quality processing. You can adjust the quality setting (1-100) for lossy formats like JPEG and WebP to balance file size and visual fidelity. ## Related tools - [Image Normalise](https://elysiatools.com/en/tools/image-normalise): Normalise image histogram to enhance contrast by stretching the intensity range (British spelling) - [Image Overlay Blend](https://elysiatools.com/en/tools/image-overlay): Apply overlay blend mode between two images to enhance contrast and create dramatic effects - [Image Transpose](https://elysiatools.com/en/tools/image-transpose): Transpose images by flipping vertically then horizontally (across the main diagonal from top-left to bottom-right) - [Image Transverse](https://elysiatools.com/en/tools/image-transverse): Transverse images by flipping horizontally then vertically (across the secondary diagonal from top-right to bottom-left) - [Add Glow Effect](https://elysiatools.com/en/tools/image-add-glow): Add beautiful glow effects to images with customizable color, intensity, size, and style variations - [Add Noise Effect](https://elysiatools.com/en/tools/image-add-noise): Add various types of noise effects to images with customizable intensity and parameters - [Add Shadow Effect](https://elysiatools.com/en/tools/image-add-shadow): Add realistic shadow effects to images with customizable direction, blur, color, and intensity - [Add Texture Effect](https://elysiatools.com/en/tools/image-add-texture): Add various texture overlays to images with customizable blend modes and intensity ## Samples - [Web Image Processing Python Samples](https://elysiatools.com/en/samples/web-image-processing-python): Web Python image processing examples using PIL/Pillow including reading, saving, resizing, and format conversion - [Web Image Processing TypeScript Samples](https://elysiatools.com/en/samples/web-image-processing-typescript): Web TypeScript image processing examples including image read/save, scaling, and format conversion - [Android Image Processing Java Samples](https://elysiatools.com/en/samples/android-image-processing-java): Android Java image processing examples including reading/saving images, scaling, and format conversion - [Android Image Processing Kotlin Samples](https://elysiatools.com/en/samples/android-image-processing-kotlin): Android Kotlin image processing examples including reading/saving images, scaling, and format conversion ## Related content - [Image Edge Detection and Convolution Kernel Lab](https://elysiatools.com/en/hubs/image-edge-detection-and-convolution-kernels): Extract the luminance channel, suppress noise with a recorded radius, compare Sobel, Prewitt, Roberts, and Laplacian operators, tune thresholded edge detection, and reproduce the winning result as an explicit convolution kernel.