If you’re not a technical person, the thought of any kind of histogram is a bit intimidating. But histograms are actually really simple and helpful once you know how they work, especially the Lightroom histogram.
Where is the histogram in Lightroom?
The Lightroom histogram is visible in both the library module and the develop module on right at the top. It’s interactive in the develop module only.
In the library module it’s purely for reference, while in the develop module you can actually make changes by clicking and dragging within the histogram.
More on how to use it in a moment…
How do I turn off histograms in Lightroom?
The histogram doesn’t have to be visible.
Any time that you feel it’s taking up too much screen space and you don’t need it, like any of the other panels, you can close it by clicking on the little triangle in the top right of the panel.
How should a histogram look in Lightroom?
It’s worthwhile noting that there isn’t a perfect histogram shape.
Just like with your camera histogram, the shape of a Lightroom histogram depends very much on the tones in the image and the lighting conditions.
For these three images:
- Aperture, shutter speed and ISO were all the same.
- I also used the same light modifier on my flash to light them and with the outdoor image combined flash with natural light.
- Same model, wearing black clothing.
The only technical difference was focal length. That has nothing to do with the shape of the histogram, but I thought I’d mention it for clarification.
Incidentally, being able to see camera settings is a great automatic feature of the Lightroom histogram!
Here’s what did have an impact on the histograms for these photos – background:
- First image – light background
- Second image – dark background
- Third image – varied background with light and dark colors
How do I use a histogram in Lightroom?
To understand how to use a Lightroom histogram, you need to know:
- Areas of the Lightroom histogram
- Types of histograms in Lightroom – luminance and color
- what the peaks and troughs mean in histograms
- How to see underexposure and overexposure in the histogram
- Editing directly in the histogram
1. Areas of the Lightroom histogram
The Lightroom histogram has 5 different zones. From left to right they are:
- Exposure (in other words midtones)
If that sounds familiar, it’s because they’re also the names of sliders in the basic panel in the develop module. This, by the way, is a clue to how to use the Lightroom histogram and why it’s so helpful.
When you hover your cursor in the different areas of the histogram you’ll see that the gray shading for that area becomes slightly lighter and the zone type appears as text below the histogram.
Speaking of hovering your cursor…
RGB histogram in Lightroom
When you move your cursor around an image, take a look at the histogram. Below the graph you’ll see the RGB values of wherever your cursor is. As you move your cursor the values change.
Two times this is particularly helpful:
- Pure white of blown out highlights (overexposed so there’s no detail) will read as R 100 G 100 B 100
- Pure black of clipped blacks (underexposed dark areas with no detail) will read as R 0 G 0 B 0
Lightroom histogram RGB values show only in the develop module histogram.
2. Types of histograms – luminance and color
In Lightroom, histograms look different for color and black and white images.
In color photos the color values of the image are depicted, so you see several histograms overlayed on each other.
The top layer, the luminance histogram, is gray and shows brightness values.
The other layers are color histograms. As color is made up of red, green and blue, you’ll see red, green and blue histograms.
You’ll also sometimes see magenta, yellow and cyan histograms when these colors feature in an image.
Black and white histograms
Black and white photos have only a luminance histogram, which is gray.
3. What do the peaks mean in a histogram?
The peaks represent where the data is in an image, so:
- A light and airy image will have a lot of peaks to the right of the image (highlights and whites) and little or none on the left (shadows and blacks)
- A high contrast image will have peaks at both ends (lights, highlights and shadows, blacks), but not necessarily much in the middle (midtones, or as Lightroom calls it, exposure)
- A flat image without much contrast will have the greatest amount of detail in the middle of the histogram.
Just like with a camera histogram, it doesn’t matter if the peaks hit the top of the histogram.
The time to be concerned is when the data pushes up against either side of the histogram. Not just near, but actually touching the sides. This indicates either:
- Underexposure – touching the left side
- Overexposure – touching the right side
This is an extreme example of underexposure.
It’s so dark that you probably can’t tell, but it’s the same image as the one above. Here I moved the exposure slider all the way to the left.
Note the histogram.
A gap at the edge of the histogram
In the histogram of the image above you’ll notice a gap on the right.
This indicates that there’s no data in the whites area, so I could slightly increase the exposure, the highlights and/or the whites to get a brighter image without risk of overexposure.
4. How to see underexposure and overexposure in the Lightroom histogram
One of the best features of the Lightroom histogram, regardless of whether your screen is correctly calibrated or not, is that you can check the histogram to be certain there’s no clipping where you don’t want it.
Clipping is a term used to describe both underexposed and overexposed areas of an image. When an image is:
- Underexposed – blacks are clipped
- Overexposed – whites are clipped
Generally, it’s okay to have some clipping in the shadows, but most of the time we avoid clipping the highlights as we want to retain detail in the highlights.
Clipping indicators in Lightroom
There’s a triangle on each side of the histogram at the top. These change color from dark gray when there’s clipping:
- Left triangle – blacks
- Right triangle – whites
These two histograms are from the same image:
- In the left histogram the blacks are clipped, because I decreased blacks by -100.
- In the right histogram the highlights are clipped, because I increased exposure by 3.
How to see clipping on the image in Lightroom
But you don’t have to refer to just the histogram to see under and over exposure.
The affected areas in the image can also be switched on in Lightroom, just like you would switch on “blinkies” on your camera histogram.
- Clipped blacks show as blue areas
- Clipped highlights show as red areas
Lightroom gives you a few choices to make it show up:
- Hover for a quick look at clipping
- Click the triangle for the clipping indicator to show until you click again to turn it off
- Press J on the keyboard to turn clipping indicator on and off
Below are the edited images to go with the above histograms.
How to change brightness levels directly in the Lightroom histogram
Instead of the using the sliders in the basic panel, to change the brightness of any of the areas in the histogram just:
- Place your cursor in the relevant part of the histogram
- Click and drag the cursor
- Drag right for more
- Drag left for less
So, for example, if you want to darken the shadows:
- Click in the shadow area of the histogram
- Drag your cursor to the left
- When you’re happy with the result, release the cursor
You could achieve exactly the same result by clicking on the shadows slider and dragging left. It’s just another way to do it.
You’ll notice how the shape of the histogram changes as you do it.
Which brings me to the next very important point about how Lightroom histograms work…
How all edits affect the Lightroom histogram
As you edit in Lightroom the histogram shape changes.
The only edit that doesn’t affect it is spot removal, unless of course you have a picture of a black cat in snow and use the spot removal tool to remove the black cat. Then you’re left with just whites and no blacks, which of course would alter the histogram. But that’s an extreme example.
Experiment with all the controls in Lightroom and double check your edits against the changes in the histogram, to see how helpful it is.
Here are two examples to show you what I mean…
For the above image I took the clarity slider all the way to the right. And then I took it all the way to the left for the below image.
Note the changes in the histograms.
RGB tone curve
In the above image I selected the red channel in the tone curve, clicked in the center and dragged the curve down to remove reds from the image, which made it more cyan.
Below I did the opposite and by increasing reds, reduced cyan.
Note how the red peak has moved in the histogram from the darks area to the exposure (midtones) area.
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