The Histogram is used to measure how much or how little light there is in an image. To read the histogram you start from the left side which has a value of 0 (lowest value) and from the left you move towards the right which has a value of 255(highest). If an image has a lot of that black shadow (content that looks like a mountain range shown in the image above) on the left half of the Histogram then the image is most likely underexposed (which means there is not enough light in the image).
|This histogram reflects an image with a lot of shadows (very dark)|
|This histogram reflects an image with a lot of light (very bright)|
One of the main goals of a photographer when taking pictures is to create correctly exposed images (imagine if you're shooting for a wedding and most of the images are underexposed, AND you don't know how to correct it on the PC!!! Trouble.). As some of you might have already guessed the best way to have a correctly exposed image is to maintain the black shadow of the histogram between the 0 and 255 values, as shown in the first image above with the caption "Histogram".
|This image has a histogram that looks similar to the first image,|
but with more black shade on the right half;
Question, can you guess why there is more shade on the right?
If you have any questions/comments go ahead and comment below or send me a message to my email firstname.lastname@example.org