๐ Image Histogram Viewer
Drag and drop an image, or click to select
Upload an image to see a histogram of how many pixels fall at each brightness level (0-255) for the red, green, and blue channels, as well as overall luminance. Useful for checking a photo's exposure and color cast at a glance.
How to use
- Drag and drop an image, or click to select a file.
- The histogram for each channel and luminance is shown automatically.
FAQ
What does the histogram tell me?
The horizontal axis is brightness (0 = darkest, 255 = brightest), and the vertical axis is how many pixels have that brightness. A peak shifted left means a darker image, shifted right means a brighter one, and spikes at either extreme suggest clipped highlights or crushed shadows.
How is luminance (the gray line) calculated?
It's computed from each pixel's RGB values using weights that reflect human eye sensitivity (luminance = 0.299รR + 0.587รG + 0.114รB) โ the same standard luminance formula used in broadcast television (equivalent to ITU-R BT.601).
Is the image uploaded to a server?
No. All processing happens entirely in your browser โ the image is never sent to a server.