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Uncovering the Basics of the Histogram


Guest post from Lora and Ted of Swinson Studios. Located in Denver, Colorado, Swinson Studios  specializes in fun and fresh portrait & wedding photography. Their unobtrusive  style allows them to capture the genuine moments that often go unnoticed.

If we’re being honest, we spent the first year of our business ignoring the histogram.  It was daunting and scary and too much ‘math’ for our heads.  In all reality, we should kind of be embarrassed.  Knowledge is power, and who doesn’t want more power when tackling the beast of Photoshop? We want you to learn from our ignorance and to understand what histogram is telling you… so, let’s do just that!

Just looking at the histogram can make anyone queasy. There is so much information packed into this little graph in Photoshop. The first step is to make sure you are seeing the histogram. If you do not, go to the menu, then window>histogram.

Now there are a couple of ways to display the histogram. Below you can see the three different views. When clicking the corner button, you’ll be given these three options:

(1) Expanded View, (2) Compact View  and (3) Channels View

Figure1

It is our personal preference to view the histogram in the (1) Expanded View. The only major difference between the three is the (3) All Channels option will show you the red, green and blue histograms separately.

Figure2

You also have the option to change the way you view the histogram in the Channel drop down menu. We prefer the RGB channel option, but it’s entirely a personal preference.

So, what is a histogram anyway? The histogram looks like a mountain range that is made up of all the information contained in your photo. It will be the backbone to all of your brightness and color adjustments.

Figure3

The width (A) of the mountain represents your photo’s brightness/tonal range (the range of colors between the darkest and lightest pixels, on a scale of 0 to 255). 0 represents pure black and is on the far left, and 255 represents pure white and is on the far right. A histogram will have a total of 255 tonal values (0-255).

Now, what about the height (B)? The height of your mountain range is telling you how many pixels of your image are lying in that specific brightness/tonal range. You can see in the image above that the brightness/tonality of the image is leaning more toward right side (lots of light grey and white tones) by the tallest and thickest mountains being farther to the right. There are not many dark tones in this photo and you can see that because there are not many ‘mountains’ located on the left side of the histogram. In a perfect world, we would want to see the mountain range dispersed evenly throughout the graph.

Knowing how to read your histogram will also let you easily see when you have clipped your blacks or whites. The mountains  will be pushed off the right or left edge of the graph. Being natural light shooters 99% of the time, there are times that we will clip small amounts on either or both ends and we are okay with that, as long as it is not a crucial part of the photo. Let’s look at a few examples…

Figure4

The entire image here is overexposed and we are close to the highlights being clipped (or blown).

Figure5

Not only is this image underexposed overall, we have clipped the blacks (shadows) entirely.

Figure6

Here we are pretty dang close to perfect exposure. The histogram, though, is telling us that we may have clipped a tiny amount of shadows, which is fairly miniscule in the scheme of the overall exposure and not something we worry about.

Let’s look at a few more images and what their histograms are telling us. Remember, we want the information dispersed evenly throughout.

Figure7

Overexposed: Most of the information is on the right side and we have blown some highlights.

Figure8

Underexposed: The information is falling closer to the left side of the graph, as well as clipping a small amount of high-lights in the background.

Figure9

Properly exposed: The information is dispersed more evenly throughout… with really no clipping on either end.

We are by no means the ultimate Photoshop gurus, but we do feel that in order create the best possible image we must understand the numbers that dictate exposure. This will help us deliver accurate and spot-on prints that our clients will love.

If you would like to go in-depth with Swinson Studios and take control of Photoshop, join us for our workshop at The Photographer Within. We rely on the histogram for every image and print that we deliver to our clients. The histogram is the foundation of everything we do as photographers and hopefully we have shed some light on the mystery that is the histogram.

To see more work from Swinson Studios, check out their website, Facebook, and Google+.

One Response to “Uncovering the Basics of the Histogram”

  1. Very nicely done. The histogram has always been somewhat a mystery to me, so thanks, this will nudge me to revisit this again. And, yes, I would like to see more.

    Thank you for your time and effort. RoseMarie