What Is A Histogram In Photography – Histograms Explained!

Getting your images to look great is all about getting smooth, even exposure -- not too dark, not too bright, but just right. Histograms are one way to help you get your images to look their best. You'll find histograms in your digital camera and in graphics applications like Photoshop. The great news is, wherever you find 'em, histograms always work the same way. In today's video, you'll get an easy to understand run through of exactly how histograms work so you can make your images look their best. Let's jump into it!

Show Notes

Here are some additional links and resources mentioned in today's tutorial. Enjoy!


Getting even exposure in your images is key to making them look great -- whether it's images for your website, product photos, or other graphics you have. And it's hard to tell if your images look decent just by visually looking at them on a computer monitor.

Sometimes you get reflected light or ambient light from the room you're in. Sometimes we even have our own internal visual biases. This is really where histograms come in. A histogram is not going to lie.

Essentially, histograms display the tonal data in your image, in a graph format, to tell you what's going on inside the image and in terms of the exposure.

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Histograms are used in a bunch of different places. Your digital camera has a histogram. Smartphone cameras have histograms. Photoshop has histograms in a bunch of different places. There's the histogram panel inside Photoshop. The levels dialog box has a histogram, the curves dialog box has a histogram -- so you'll find histograms in a variety of different places.

The good news is that they all work exactly the same way. So if you figure out histograms once, you can use them in all these different places.

So what a histogram does is it displays in images exposure -- that is, the amount of blacks, whites, and midtones, also known as the tonal values, inside your image. Histograms will tell you if your image is overexposed or underexposed.

All right, so far we know that a histogram is going to display the images exposure in a graph format. It's going to plot out the distribution of light and dark pixels inside your image. But here's specifically how they work: A histogram has a horizontal axis going from left to right. The bottom-left corner represents 100% black. The bottom-right corner represents 100% white.

If it's easier for you, you could say that the horizontal axis goes from 100% black in the bottom-left to 0% black in the bottom-right. Then, the halfway-point represents 50% black, or gray.

The vertical axis displays the number of pixels in that particular area of the image -- the dark areas, the light areas, and the mid tones. The height of vertical scale really is determined by the number of pixels inside your image.

So, dark areas, midtones and light areas will have a certain number of pixels plotted in those areas inside any given image's histogram. That's how it works. So, you could call the far-left of the image pure black, or absolute black. And you could call the far-right side of the histogram graph pure white, or absolute white.

A histogram that displays pixels clumped to the left of the histogram graph is called underexposed. And a histogram that displays too many pixels clumped over to the right is considered to bright, or overexposed. Ideally, what we want is a histogram that displays some pixels on the left, some pixels on the right and pixels distributed throughout the mid tones. This would be a well exposed image. Tools like Curves and Levels inside Photoshop allow us to adjust or manipulate an image's exposure to help balance the amount of light and dark pixels in the image thus evening out it's tonal values or it's exposure.

Alright, there you go. That's pretty much the gist with histograms, how they work, and how to read them. And of course, once you start colour correcting images, you want to make sure that you have nice even exposure. You can tell right away when you're using a histogram whether that image is overexposed, underexposed, or bang on the money.

So that's our look at histograms and how they work. I hope you enjoyed. I tried to simplify histograms as much as possible. I know this stuff can be kind of confusing, so I hope this has all made sense.

Hope you enjoyed. See ya next time!

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Geoff Blake, Ten Ton Online

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