How to Read a Histogram
The left side of the histogram represents the maximum dark values that your camera can capture. The right side represents the maximum white values your camera can capture.The histogram’s left to right directions in the graph are related to the darkness and lightness of the image, while the valleys and peaks (up and down points) of the histogram have to do with color information. That was pretty technical wasn’t it? Whew, let’s see if I can break it down a bit.
When you see the three histograms next to each other it makes more sense doesn't it? The graph on the left is underexposed and shifted to the left, while the graph in the middle represents a well exposed image with both edges touching the sides of the graph. The graph on the right represents an overexposed image and you can see the graph crammed and tipped to the right. This is the very graph that helped me to understand and read a histogram.
Another way of learning to read the histogram graph
The higher the graph in each column, the more pixels in that shade of lighter or darker in your photo. Like a map telling us how our images are exposed. All digital photos whether black and white or color show a histogram.
Let’s look at the following histograms.
- Pure black pixels are all zeros and will show up on the very left of the histogram graph.
- Pure white pixels are at the value of 255 and will show up on the very right of the histogram graph.
- Look up 3 photos on your computer and see if you can view the image histogram for the photo(s) you choose. If you do not have software such a Aperture or Photoshop that allows you to view the histogram for that image, do a search for images via the internet showing histograms. What did you discover?