About the Image Histogram Viewer
A histogram is a chart of all the pixel values in a picture, from the darkest tones on the left to the brightest on the right. It tells you at a glance whether a photo is too dark, too bright or flat, and whether parts have been lost to pure black or pure white. Drop a photo here and this viewer draws the red, green and blue histograms or the brightness histogram, with an optional log scale, and lists the average brightness, the median, the contrast and the share of pixels that are pure black and pure white. A short plain-language hint tells you what the numbers suggest. The photo is analysed in your browser and never uploaded.
Updated October 2026
How to use the Image Histogram Viewer
- 1Drop a photo.
- 2Look at the histogram: dark tones on the left, bright on the right.
- 3Switch between red, green, blue and brightness.
- 4Turn on the log scale to see small peaks.
- 5Read the numbers and the exposure hint.
Reading the shape
A histogram bunched to the left belongs to a dark photo, one bunched to the right to a bright one, and one squeezed into the middle to a flat, low-contrast picture. A flat picture often looks dull and can be improved by stretching the contrast. A picture with spikes at both edges has strong contrast with clipped detail at both ends.
Look at the red, green and blue channels separately when the colours look off. If the blue channel sits to the right of the red channel, the photo has a blue cast, typical of shade or cold light.
What to do next
- Too dark: raise the exposure or lift the shadows, if the shadows are not already crushed.
- Too bright: lower the exposure or pull back the highlights.
- Flat: increase contrast so the histogram spreads out.
- Colour cast: adjust the white balance.
- Clipped highlights: next time, expose for the highlights or use bracketing.
- Check your edit again afterwards; the histogram updates with the new file.
Related tools
Adjust brightness and contrast in the Photo Editor, turn the picture grey with the Black and White Image tool, or sample exact colours with the Image Color Picker. To read the camera settings behind a photo use the EXIF Data Viewer, and to make the file smaller use Compress Image. A histogram is a guide; trust your eyes too.
Features
- Red, green, blue and brightness histograms
- Linear or log scale
- Average, median and contrast
- Percentage of pure black and pure white
- Plain-language exposure hint
- Preview of the photo
- Private, nothing is uploaded
Frequently asked questions
How do I read a histogram?
The left side shows shadows, the middle shows midtones and the right side shows highlights. The higher the chart at a point, the more pixels have that brightness.
What does a peak at the far right mean?
A tall bar at the right edge means many pixels are pure white. Detail there is lost and cannot be recovered, which is called blown highlights.
What does a peak at the far left mean?
It means many pixels are pure black, often because the shadows are crushed. Some black is normal, for example in a night scene.
What is a good histogram?
There is no perfect shape. A good histogram usually uses the full range without piling up at the edges. A dark photo of a night sky or a bright photo of snow will legitimately lean to one side.
Why do the colours matter?
If one colour channel peaks at the right edge while the others do not, that colour is clipped and its detail is lost. A colour cast shows as the channels being shifted apart.
Is the histogram of the original or a shrunk copy?
Large photos are scaled down to 1200 pixels before counting, which has almost no effect on the shape.
Is my photo uploaded?
No.