lovelifey: [Photography] A Practical Guide to the Lightroom Histogram

The post A Practical Guide to the Lightroom Histogram appeared first on Digital Photography School. It was authored by Andrew S. Gibson.

If you want to achieve the best results when editing in Lightroom, you must master the histogram.

But what actually is the Lightroom histogram? What does it show? And how does it work?

In this article, I explain everything you need to know, including:

What the Lightroom histogram displays
How you can use the histogram to identify (and fix) clipped highlights and shadows
How you can use the histogram to determine ideal exposure and contrast levels
A simple, step-by-step method of incorporating the histogram into your editing workflow

So if you’re ready to start enhancing your photos with a bit of histogram knowledge, then let’s dive right in, starting with the basics:

What is the Lightroom histogram?

The Lightroom histogram is a graphical representation of the tones and colors in a photo. It offers a fast, precise way to check each image for exposure and contrast issues.

You see, every image features a range of tones, from the deepest blacks to the brightest whites. The histogram simply displays these different tones as peaks:

The rightmost portion of the histogram represents the brightest part of an image, while the leftmost portion of the histogram represents the darkest part of an image. The areas in the center of the histogram, then, represent the midtones of an image.

So if an image features lots of bright areas, you’ll see peaks at the right end; if an image features lots of dark areas, you’ll see peaks at the left end; if an image features lots of midtones, you’ll see peaks in the center. Quickly glance at a histogram, and you’ll gain a rough sense of how light – or dark – an image appears. Make sense?

Note that the Lightroom histogram is found in two places:

At the top of the right-hand panel in the Library module, and at the top of the right-hand panel in the Develop module. You can easily check an image histogram when managing your files in the Library module, and you can also reference the histogram when applying edits in the Develop module.

The Lightroom histogram two different locations

While the Lightroom histogram is a relatively simple tool, it’s actually hugely helpful, as you’ll see in the next section:

What does the Lightroom histogram tell you?

The Lightroom histogram indicates three useful image characteristics:

Image clipping
Image exposure
Image contrast

Let’s take a look at each item in turn:

Image clipping

Clipping refers to a loss of detail at the extreme ends of an image file. For instance, if you dramatically overexpose an image, you may lose detail in – that is, clip – the brightest parts of the file, such as the sky.

Or if you dramatically underexpose an image, you may clip the darkest parts of the file, such as heavy shadows.

Clipping is a problem, as images tend to look best when detail is present in every tonal area. Fortunately, if you can identify clipping and you haven’t messed up your exposure too badly, you can often recover clipped details by adjusting your Lightroom exposure sliders.

Of course, before you can recover clipped details, you need to determine whether clipping is present, which you can do via the Lightroom histogram.

The simplest method to check for clipping is to just look at the histogram. If peaks are pressing up against the leftmost edge of the graph, then you’re probably dealing with shadow clipping, and if peaks are pressing up against the rightmost edge of the graph, then you’re probably dealing with highlight clipping.

But it’s always a good idea to get confirmation. Simply click the Show Shadow Clipping and Show Highlight Clipping triangular icons at the top of the histogram (circled below):

The Lightroom histogram clipping indicators

(Alternatively, hit the J key on your keyboard.)

Then check your image. If shadow clipping is present, you’ll see areas marked in blue:

And if highlight clipping is present, you’ll see areas marked in red:

The Lightroom histogram clipped highlights

At this point, you might boost the Shadows slider to recover clipped shadow detail, and you might drop the Highlights slider to recover clipped highlight detail. When editing images in Lightroom, I highly recommend you keep these clipping indicators on – and that you check the histogram frequently. You never know what adjustment might send your tones over the edge!

Here, I dropped the Highlights slider to -100, and the detail came right back into the sky:

Image exposure

The Lightroom histogram can also indicate whether your image is over- or underexposed.

You see, a well-exposed image tends to produce a relatively centered histogram, one with tones spread across the graph:

A Lightroom histogram with a balanced exposure

But if you look at the histogram and see a clear skew – where the tones are pushed to the right or the left – it’s a sign that your image is poorly exposed. Here’s an example of a skewed histogram that indicates potential underexposure:

The Lightroom histogram underexposed image

A look at the photo confirms the histogram is correct. The image is far too dark and needs some serious exposure correction:

You should be careful, however. While a skewed histogram generally does indicate a problematic exposure, certain images feature a natural tonal imbalance; in such cases, a perfect exposure will produce a skewed histogram.

For instance, if you’re photographing a black cat against dark carpet, you should see a histogram like the one below, as the image contains no light tones:

And if you’re photographing a polar bear against snow, you should get the opposite: a heavy skew toward the right edge of the histogram and no peaks along the left end of the graph.

So do check your histogram for bad exposures, but also check your image and evaluate its tonal range. Only then should you adjust the exposure by moving the Lightroom Tone sliders.

For the underexposed image I shared above, a boost of the Exposure slider improved the shot dramatically:

Image contrast

While most photographers use the histogram to determine clipping and overall exposure issues, you can use the histogram a third way:

To identify images in need of a contrast boost.

You see, a low-contrast image features a limited tonal range. Most low-contrast shots consist of midtones (with little-to-no highlight and shadow presence), though you can also find low-contrast photos that consist of highlights and midtones or midtones and shadows.

These low-contrast images feature a compressed histogram, where the peaks bunch together and fail to span the entire graph:

This often occurs in flat light, when photographing on overcast days or in strong shade. The histogram displayed above belongs to this image, which was taken during very cloudy conditions:

low-contrast photo of rocks on a cloudy day

Now, low-contrast images aren’t necessarily bad. You can sometimes use a low-contrast edit to create a faded, even ethereal, effect.

But more contrast will help your photos pop, so unless you have a specific reason to keep your shots low contrast, I recommend you respond to a compressed histogram by boosting the Contrast slider and/or adjusting the Blacks and Whites sliders.

That’s what I did for my image, and the result is far better:

high-contrast corrected image of rocks on a cloudy day

How to use the Lightroom histogram: a step-by-step workflow

In this section, I explain how to use the histogram to quickly enhance your photos.

Step 1: Check for highlight and shadow clipping

The Lightroom histogram lets you quickly check files for highlight and shadow clipping.

So open an image in the Develop module, then tap the Show Highlight Clipping and Show Shadow Clipping icons:

Take a look at your image. Is there any highlight clipping? (This will be indicated by a red overlay.)

If so, head over to the Highlights slider and reduce the value until the clipping disappears.

Then look for shadow clipping, indicated by a blue overlay. If clipping is present, boost the Shadows slider until the lost detail is recovered.

Step 2: Check the overall exposure

Once you’ve eliminated clipping, it’s time to deal with any general exposure issues.

Check out your histogram. Is it well balanced? Or does it seem to indicate over- or underexposure?

If it does seem well balanced – especially when taking into account the image’s content – then you can move on to the next step. However, if the exposure appears to be inappropriately skewed, then find the Exposure slider and drag it to the right (to boost the exposure) or to the left (to drop the exposure).

As you work, keep an eye on your histogram. And make sure you keep the clipping indicators activated; that way, if you do start to clip details, you can quickly back off your exposure adjustments (or you can add a Shadows or Highlights adjustment to compensate).

Step 3: Check image contrast

At this point, I’d recommend observing your image. How does it look? Is it well exposed? And if so, does it look sufficiently punchy?

Then check your histogram once more, looking for the compression that’s characteristic of low-contrast photos.

If you do notice a compressed, low-contrast histogram, then I’d suggest increasing the Contrast slider to see how it affects your shot.

If you like the effect, then leave it; if you prefer a low-contrast effect, then double-click to reset the Contrast slider.

By the way, if you find the Contrast slider too heavy-handed, you do have another option: You can decrease the Blacks slider while increasing the Whites slider. This is a nice way to add some weight to the image extremes, and it’ll give you a bit more control than the standard Contrast slider.