A photography histogram displayed in Adobe Lightroom.
Last Update: November 7, 2026
Quick Jump
- What Is a Photography Histogram?
- Why Histograms Matter
- How to Read a Histogram
- Using Histograms to Improve Exposure
- Luminance vs RGB Histograms
- Understanding Histogram Clipping
- Exposing to the Right (ETTR)
- Camera Histogram vs Lightroom Histogram
- Using Histograms for Concert Photography
- Using Histograms for Landscape Photography
- Histograms in Lightroom and Photoshop
- Common Histogram Mistakes
- Practical Histogram Workflow
- Frequently Asked Questions
A photography histogram is one of the most useful tools available to photographers, yet it's often overlooked or misunderstood.
You can look at the image preview on your camera and think the exposure looks correct, only to discover later that important highlights have lost detail, shadows are too dark, or the image needs more editing than expected.
A histogram gives you another way to evaluate exposure. Instead of relying entirely on how an image looks on your camera's LCD screen, you can see how its brightness values are distributed, from the darkest shadows to the brightest highlights.
Learning how to read a histogram can help you:
Evaluate exposure more accurately
Identify potential highlight and shadow clipping
Understand the tonal range of an image
Preserve important image detail
Make better exposure decisions in difficult lighting
Whether you're photographing concerts, landscapes, portraits, or wildlife, understanding the histogram can help you capture better-exposed photographs and make more informed editing decisions.
This guide explains how photography histograms work, how to interpret them, and how to use them in real-world shooting and editing workflows.
What Is a Photography Histogram?
A photography histogram is a graph that shows how brightness values are distributed throughout an image.
The horizontal axis represents brightness, ranging from black on the far left to white on the far right. The vertical axis represents how many pixels fall within each brightness level.
In simple terms:
Left side: Shadows and dark tones
Middle: Midtones
Right side: Highlights and bright tones
The higher the graph rises at a particular point, the more pixels in the image have that brightness value.
A histogram does not show where those pixels appear in the photograph. It only shows their overall tonal distribution.
It also doesn't tell you whether an image is properly exposed or aesthetically pleasing. Instead, it provides information you can use to decide whether the exposure matches your subject and creative intent.
Examples of Different Histograms
Different scenes naturally produce different histogram shapes.
Dark concert photograph
A concert photograph with a black stage background and dark surroundings may have most of its information toward the left side of the histogram. A few bright stage lights or illuminated faces may create peaks farther to the right.
Bright landscape photograph
A beach scene photographed in bright sunlight may have more information toward the right because of reflective water, bright sand, and sunlight.
High-contrast photograph
A scene containing deep shadows and bright highlights may have information spread across most of the histogram, sometimes with gaps in the middle.
None of these distributions is automatically wrong. The important question is whether the tones you want to preserve are being recorded.
Why Histograms Matter for Photographers
The biggest advantage of using a histogram is that it provides exposure information that can be difficult to judge from your camera's LCD screen alone.
Your camera display can be misleading because the appearance of an image changes depending on:
LCD brightness settings
Viewing angle
Direct sunlight or surrounding light
Camera picture style and display settings
A photograph that looks properly exposed on the camera screen may contain clipped highlights or overly dark shadows.
The histogram gives you another reference point when evaluating exposure.
Histograms Help Protect Important Detail
One of the most useful things a histogram can reveal is potential clipping.
Highlight clipping occurs when bright areas exceed the camera's ability to record additional tonal information. Those areas may appear completely white, with no recoverable detail.
Examples include:
Bright concert spotlights
Clouds during sunrise or sunset
Reflections on water
White clothing in direct sunlight
Shadow clipping occurs when dark areas fall below the camera's ability to record usable detail.
Examples include:
Black clothing
Dark stage backgrounds
Nighttime landscapes
Deep forest shadows
Some clipping is perfectly acceptable, depending on the photograph. However, losing detail in an important part of the image can limit your editing options.
Histograms Improve Your Editing Flexibility
A properly exposed RAW file generally provides more flexibility during post-processing.
Monitoring the histogram can help you avoid unnecessary exposure problems and preserve important tonal information.
This is particularly useful for:
Concert photography with difficult stage lighting
Landscape photography with bright skies and dark foregrounds
Portrait photography where skin tones need careful exposure
Commercial photography where consistent image quality matters
How to Read a Photography Histogram
Reading a histogram becomes much easier once you understand its three general tonal regions.
The Left Side: Shadows
The left side represents the darkest portions of the photograph.
A histogram with a large amount of information toward the left usually indicates that the image contains substantial dark areas.
This is common in:
Night photography
Concert photography
Dramatic portraits
Forest and woodland scenes
A histogram leaning toward the left does not automatically mean the photograph is underexposed.
For example, a concert photograph with a dark background may be correctly exposed even though most of the histogram is concentrated in the shadows.
Pay particular attention to whether important shadow details are being lost.
The Middle: Midtones
The center of the histogram represents midtones, which fall between the darkest and brightest values.
This includes many everyday details, such as:
Skin tones
Clothing
Landscape textures
Buildings and other surfaces
Many photographs contain substantial midtone information, but there is no requirement for the histogram to peak in the center.
The Right Side: Highlights
The right side represents the brightest areas of the image.
Common examples include:
Bright skies
Sunlight
Reflections
White objects
Stage lighting
Watch the far-right edge carefully. If the graph reaches the edge, some pixels may be clipped.
A peak against the right edge does not necessarily mean the entire image is overexposed. It may simply represent a small number of extremely bright areas.
The important thing is determining whether those areas contain detail you want to preserve.
Using Histograms to Improve Exposure
The histogram is most useful when you treat it as a decision-making tool rather than a target you need to match.
A common beginner mistake is assuming every properly exposed photograph should have a smooth, centered histogram.
That isn't true.
Different subjects and lighting conditions produce different tonal distributions.
The Goal Is Not Always a Centered Histogram
Consider these examples:
Night concert photography
Large areas of darkness
Bright stage lights
Uneven tonal distribution
Snow landscape
Mostly bright tones
Relatively little shadow information
Histogram weighted toward the right
Silhouette photography
Large areas of dark tones
Small areas of bright detail
Histogram weighted toward the left
Trying to force these histograms toward the center would often produce worse photographs.
Expose for the Important Parts of the Image
Instead of asking whether the histogram looks balanced, ask whether the important details are properly exposed.
For example:
Concert photography
Prioritize performer faces and expressions.
Watch for excessive clipping in skin tones and clothing.
Accept that some spotlights and colored stage lights may lose detail.
Landscape photography
Pay attention to bright skies and reflections.
Preserve important foreground and shadow detail.
Consider exposure bracketing when the scene exceeds the camera's dynamic range.
Portrait photography
Pay attention to skin tones.
Avoid losing important facial highlights.
Maintain natural-looking shadows.
The histogram is a guide, not a rule. Your subject, lighting, and creative intent should determine the exposure you choose.
A DSLR camera with the histogram display.
Luminance vs. RGB Histograms
Most cameras and photo editing programs offer more than one type of histogram.
The two most common are:
Luminance histogram
RGB histogram
Understanding the difference can help you evaluate both brightness and color exposure.
Luminance Histogram
A luminance histogram represents the overall brightness distribution of an image, combining information from its red, green, and blue color channels into a single tonal graph.
It is useful for:
Evaluating general exposure
Checking shadow and highlight distribution
Identifying potential tonal clipping
Making quick exposure adjustments
For many photographers, the luminance histogram is the most practical option for everyday exposure decisions.
RGB Histogram
An RGB histogram displays the red, green, and blue channels separately.
This provides additional information that a single luminance histogram may not reveal.
An image can appear reasonably exposed on its luminance histogram while one of its individual color channels is clipping.
This is particularly relevant when photographing subjects under intense colored lighting.
Example: Red Concert Lighting
Concert photographers frequently encounter saturated red, blue, and purple stage lighting.
A performer illuminated by a strong red spotlight may have a red channel that reaches the far-right edge of the histogram, even when the overall brightness appears acceptable.
An RGB histogram can help identify:
Clipped red, green, or blue channels
Potential loss of color detail
Uneven color exposure
Which Histogram Should You Use?
Both are useful, but they serve slightly different purposes.
Luminance histogram
Best for general exposure evaluation and tonal distribution.
RGB histogram
Best for identifying individual color channel clipping and evaluating saturated colors.
For concert photography, the RGB histogram can be particularly helpful because of rapidly changing colored stage lighting.
For landscape photography, it can help when photographing saturated sunsets, colorful skies, and highly reflective scenes.
Understanding Histogram Clipping
Histogram clipping occurs when pixels reach the limits of the available tonal range and additional detail can no longer be recorded or displayed.
There are two main types:
Highlight clipping
Shadow clipping
Highlight Clipping
Highlight clipping occurs when bright areas exceed the camera sensor's recording capacity.
Those areas may become completely white, with no recoverable detail in the affected channels.
Common examples include:
Bright sunlight
Stage spotlights
Reflections on water
Clouds during sunrise or sunset
How to Avoid Unwanted Highlight Clipping
Depending on the situation, you can protect highlights by:
Lowering exposure
Using exposure compensation
Reducing ISO when appropriate
Adjusting aperture or shutter speed
Enabling highlight warnings
Shooting RAW for greater editing flexibility
Keep in mind that RAW files may retain highlight information even when the camera's histogram or highlight warnings indicate clipping. This is because most cameras generate their histogram from an embedded JPEG preview rather than directly from the untouched sensor data.
However, you should not assume every clipped highlight can be recovered.
Shadow Clipping
Shadow clipping occurs when dark areas fall below the camera sensor's ability to record usable detail.
This can produce completely black areas with little or no recoverable information.
Common examples include:
Dark clothing
Nighttime scenes
Black stage backgrounds
Deep forest shadows
Underexposing an image too heavily can also create noisy shadows when you attempt to brighten them during editing.
Should You Always Avoid Clipping?
No.
Clipping isn't necessarily a problem if it occurs in areas where detail isn't important.
For example:
A silhouette intentionally uses dark areas without visible detail.
A concert photograph may contain clipped stage lights.
The sun itself may appear completely white in a landscape photograph.
The goal isn't to eliminate all clipping. It's to avoid losing important information unnecessarily.
Exposing to the Right (ETTR)
Exposing to the Right, commonly called ETTR, is a technique that involves capturing a RAW image as brightly as possible without clipping important highlights.
The idea is to move the histogram toward the right side while preserving the detail you need.
Why does this work?
Digital camera sensors capture more tonal information in brighter exposures than in darker ones. When a photograph is underexposed and later brightened, noise can become more noticeable, particularly in shadow areas.
A properly executed ETTR exposure can therefore produce cleaner shadows and more editing flexibility.
When ETTR Works Well
ETTR can be useful in situations where you have time to evaluate exposure and control the lighting.
Examples include:
Landscape photography
Architecture
Studio photography
Still-life photography
For example, when photographing a sunrise landscape, a slightly brighter RAW exposure may preserve more usable shadow information than a heavily underexposed image that needs significant brightening later.
When ETTR Is Less Practical
ETTR isn't ideal for every situation.
It can be difficult when photographing:
Concerts
Wildlife
Fast-moving subjects
Unpredictable lighting conditions
In these situations, trying to maximize exposure can cost you important moments or cause unwanted highlight clipping.
A reliable exposure that captures the subject properly is more important than pushing the histogram as far right as possible.
ETTR and RAW Photography
ETTR is primarily a RAW photography technique because RAW files retain more unprocessed tonal information than JPEGs.
It also requires care. The camera's histogram is usually based on a processed JPEG preview, so it may indicate clipping before the RAW data actually reaches its limit.
Avoid pushing exposure so far that important highlights are permanently clipped.
Camera Histogram vs Lightroom Histogram
The histogram you see on your camera is useful, but it is not identical to the histogram you see during editing.
This difference is important.
Camera Histogram
The in-camera histogram is generated from the camera's JPEG preview.
Even if you shoot RAW, your camera creates a processed preview to display.
This means the histogram may reflect:
picture style settings
contrast adjustments
saturation settings
It is a helpful guide, but it is not the complete RAW data.
Lightroom Histogram
The Lightroom histogram shows information from the actual imported file.
This gives you a more accurate view of:
RAW exposure
tonal adjustments
editing changes
Why This Matters
A camera histogram may show a highlight warning, but your RAW file may still contain recoverable detail.
Conversely, an image that looks fine on the camera screen may reveal problems when opened on a calibrated monitor.
Best Practice
Use the camera histogram to:
avoid obvious exposure mistakes
protect important highlights
make quick adjustments
Use Lightroom's histogram to:
refine exposure
edit accurately
prepare final images
Camera Histogram vs. Lightroom Histogram
The histogram displayed on your camera is useful while shooting, but it isn't identical to the histogram you see when editing your photographs.
Understanding the difference is important, particularly if you shoot RAW.
Camera Histogram
Even when shooting RAW, most cameras generate a JPEG preview to display on the LCD screen.
The in-camera histogram is generally based on that processed preview rather than the untouched RAW sensor data.
This means it can be influenced by camera settings such as:
Picture style or picture control
Contrast
Saturation
White balance
Highlight and shadow processing
As a result, the camera histogram is a useful exposure reference, but it doesn't provide a direct measurement of all the tonal information stored in the RAW file.
Lightroom Histogram
In Adobe Lightroom Classic, the histogram reflects the rendered image and changes as you adjust its development settings.
It provides a visual representation of the tonal distribution after Lightroom's processing and adjustments.
You can use it to evaluate:
Overall exposure
Shadow and highlight detail
Contrast
Black and white points
Individual color channels
As you adjust Exposure, Highlights, Shadows, Whites, and Blacks, the histogram updates to reflect those changes.
Why the Difference Matters
Your camera may show highlight clipping even when the RAW file still contains recoverable detail.
This is particularly common when shooting high-contrast scenes or using a picture style with increased contrast.
However, RAW files don't have unlimited highlight recovery. If the sensor has reached its recording limit, the lost information cannot be restored.
Best Practice
Use your camera's histogram to evaluate exposure while shooting and identify potential problems.
Use Lightroom's histogram during editing to evaluate the rendered image, refine tonal adjustments, and check for clipping in the final result.
Using Histograms for Concert Photography
Concert photography is one of the more challenging situations for using a histogram.
Stage lighting changes constantly. You may go from a dark stage to an intense spotlight, followed by saturated red or blue lighting, within seconds.
The histogram can help you evaluate exposure, but it needs to be used alongside your camera's metering, autofocus, and exposure settings.
What to Watch For
Protecting performer faces
The performer is usually the most important part of the photograph.
Pay attention to:
Facial highlights
Skin tone detail
Expressions
Clothing texture
Avoid underexposing the entire image just to preserve every bright light source.
Watching stage lights
Bright LEDs and spotlights frequently clip, especially during intense lighting effects.
Some clipping is normal and often unavoidable. Don't sacrifice the exposure of the performer just to retain detail in every light.
Monitoring colored lighting
Use the RGB histogram when possible to identify individual color channels that may be clipping.
This can be particularly useful during strong red or blue lighting.
Maintaining shutter speed
A histogram tells you about tonal distribution, not sharpness or motion blur.
Always prioritize an appropriate shutter speed, reliable autofocus, and timing when photographing performers.
Practical Concert Photography Histogram Strategy
Set your camera's exposure settings based on the venue and available light.
Check your histogram during soundcheck or between important moments when possible.
Watch for excessive clipping in performer faces and other important details.
Use the RGB histogram when intense colored lighting creates potential channel clipping.
Adjust exposure when necessary, but don't let histogram monitoring distract you from the performance.
For more practical advice, see my guide to best camera settings for concert photography.
Using Histograms for Landscape Photography
Landscape photography often provides more time to evaluate exposure, making the histogram particularly useful.
Scenes containing bright skies, reflective water, and dark foregrounds can exceed the dynamic range of a camera sensor.
A histogram helps you determine whether the scene can be captured in a single exposure or whether additional techniques may be needed.
Common Landscape Histogram Challenges
Bright skies
Sunrise and sunset scenes often contain bright highlights alongside darker foregrounds.
Watch for:
Clipped clouds
Lost sky texture
Overexposed reflections
Deep shadows
Forests, mountains, and coastal landscapes can contain substantial dark areas.
Check whether important shadow details are being preserved, particularly if you plan to brighten the image later.
High dynamic range
Some scenes contain more brightness variation than your camera can capture in a single exposure.
If you cannot preserve both important highlights and shadows, consider:
Exposure bracketing
Graduated neutral density filters
Blending multiple exposures during editing
Landscape Photography Histogram Tips
Shoot RAW for greater editing flexibility.
Use a low ISO when practical.
Protect important highlight detail.
Review the histogram after important exposures.
Consider bracketing when the scene exceeds your camera's dynamic range.
The goal is to capture as much useful tonal information as possible without unnecessarily compromising the image.
Histograms in Lightroom and Photoshop
Histograms aren't just useful while shooting. They're also valuable during post-processing because they show how editing adjustments affect the tonal distribution of your photograph.
Both Adobe Lightroom Classic and Photoshop provide histogram tools that help you evaluate exposure and tonal adjustments.
Using the Histogram in Lightroom Classic
In Lightroom Classic, the histogram appears in the Develop module.
As you make adjustments, the graph changes to reflect the updated image.
Common adjustments include:
Exposure: Shifts overall brightness.
Contrast: Expands or compresses tonal differences.
Highlights: Adjusts brighter portions of the image.
Shadows: Adjusts darker portions of the image.
Whites: Controls the brighter endpoint of the tonal range.
Blacks: Controls the darker endpoint of the tonal range.
For example, increasing exposure generally shifts the histogram toward the right, while reducing highlights can pull bright tones away from the edge.
The histogram provides useful feedback as you edit, but it shouldn't replace visual evaluation of the photograph.
Using Clipping Warnings in Lightroom Classic
Lightroom Classic includes highlight and shadow clipping warnings.
These can help identify areas where tonal information is being lost in the rendered image.
They are useful when editing:
Bright skies
Reflections
Stage lighting
Dark backgrounds
Nighttime photographs
Use the warnings to identify areas that deserve attention, not as a reason to eliminate every clipped pixel.
Using Histograms in Photoshop
Photoshop includes a Histogram panel that displays tonal information for an image.
It can be useful when working with:
Levels adjustments
Curves adjustments
Layer masks
Color correction
Contrast adjustments
The histogram helps you understand how your edits affect the distribution of tones throughout the photograph.
For more information about organizing and refining your editing workflow, see my guide to editing workflow for concert photography.
Advanced Histogram Techniques
Once you understand basic histogram reading, there are a few additional ways to use the tool.
Monitoring Individual RGB Channels
The RGB histogram can reveal clipping that may not be obvious in a standard brightness histogram.
A single color channel can reach its limit even when the overall tonal distribution looks acceptable.
This commonly occurs with:
Saturated sunsets
Red or blue concert lighting
Neon signs
Highly saturated subjects
Checking individual channels can help you identify potential color detail loss before it becomes a problem.
Understanding Contrast Through the Histogram
The width of a histogram can provide a general indication of the tonal range and contrast in an image.
A histogram spread across much of the graph often indicates a wider tonal range, with both dark shadows and bright highlights.
A narrower histogram may indicate a more limited tonal range, which is common in soft or evenly lit scenes.
However, histogram width alone doesn't determine image quality or contrast. The actual distribution and appearance of the tones matter too.
Using Histograms for HDR and Exposure Bracketing
Landscape photographers often use histograms when creating HDR images or blending multiple exposures.
The goal is to capture detail across a wider brightness range than a single exposure can comfortably record.
For example, a sunrise landscape may have a bright sky and a much darker foreground.
You can capture multiple exposures:
A darker exposure to preserve highlights
A middle exposure for general scene detail
A brighter exposure to capture shadow information
Reviewing the histograms helps confirm whether each exposure is recording the information you need.
These images can then be blended in Lightroom, Photoshop, or another editing program.
Common Histogram Mistakes
Histograms are useful, but they are easy to misunderstand. Here are some of the most common mistakes photographers make.
Mistake 1: Thinking Every Histogram Should Be Centered
A histogram doesn't need to peak in the middle.
A nighttime photograph may naturally lean left, while a snowy landscape may lean right.
The distribution should reflect the subject and lighting conditions.
Mistake 2: Ignoring the Actual Photograph
A histogram is only one source of exposure information.
It doesn't understand your subject, composition, or creative intent.
Always consider the photograph itself rather than relying entirely on the graph.
Mistake 3: Underexposing Everything to Protect Highlights
Being overly cautious about highlight clipping can lead to unnecessarily dark photographs.
This can create noisy shadows and reduce editing flexibility.
Protect important highlights, but don't sacrifice the overall exposure just to preserve detail in areas that don't matter.
Mistake 4: Ignoring RGB Channels
A luminance histogram may look acceptable while an individual color channel is clipping.
This is particularly relevant when photographing saturated colors, sunsets, and concert lighting.
Mistake 5: Assuming RAW Files Can Recover Everything
RAW files provide more editing flexibility than JPEGs, but they don't make highlight and shadow clipping irrelevant.
If the sensor never recorded the information, software cannot fully restore it.
Mistake 6: Forgetting That the Camera Histogram Uses a JPEG Preview
When shooting RAW, the camera histogram generally reflects the processed JPEG preview.
Picture styles, white balance, and contrast settings can influence what you see.
Use it as a practical guide, but remember that the RAW file may retain additional highlight or shadow information.
Practical Histogram Workflow
You don't need to constantly monitor your histogram to benefit from it.
A simple workflow can help you make better exposure decisions without slowing down your photography.
Before Shooting
Check that you understand your camera's histogram display and available exposure warnings.
If your camera offers an RGB histogram, learn how to access it.
Consider enabling highlight warnings if you find them useful.
During Shooting
Use the histogram to answer a few basic questions:
Are important highlights clipping?
Are important shadows losing detail?
Does the exposure match the scene?
Do I need to make an adjustment?
Check it periodically rather than analyzing every frame.
In fast-moving situations, capturing the moment is more important than constantly reviewing exposure.
After Shooting
During editing:
Review the histogram in Lightroom Classic.
Adjust exposure based on the photograph and intended result.
Check important highlights and shadows.
Review individual color channels when necessary.
Evaluate the finished image at normal viewing size.
Recommended Approach for Concert and Landscape Photography
Concert photography
Shoot RAW.
Expose for the performer rather than every light source.
Accept some clipping from stage lights when necessary.
Monitor colored lighting when practical.
Prioritize focus, shutter speed, and timing.
Landscape photography
Shoot RAW.
Protect important highlights.
Review the histogram after important exposures.
Use exposure bracketing when necessary.
Preserve shadow detail without unnecessarily brightening the entire scene.
Final Recommendations
A photography histogram is one of the simplest tools you can learn to improve your exposure decisions.
The most important takeaway is this:
Don't chase a perfect histogram. Learn what the histogram is telling you.
Use it to:
Evaluate brightness distribution
Protect important highlights
Preserve useful shadow detail
Identify potential color channel clipping
Make better exposure decisions in the field
Refine tonal adjustments during editing
For most photographers, shooting RAW, understanding clipping warnings, and reviewing the histogram when lighting conditions are difficult are good habits to develop.
The histogram won't replace your creative judgment, but it can help you capture photographs with more useful information and greater editing flexibility.
Frequently Asked Questions
What is a histogram in photography?
A histogram is a graph that shows how brightness values are distributed throughout an image, from shadows on the left to highlights on the right. It helps photographers evaluate exposure and identify potential clipping.
Should a photography histogram always be centered?
No. A centered histogram isn't always correct. The ideal distribution depends on the subject, lighting conditions, and intended appearance of the photograph. A dark concert image may naturally lean left, while a bright snow scene may lean right.
What does the left side of a histogram represent?
The left side represents the darkest tones in an image, including shadows and blacks. A large amount of information on the left indicates that the photograph contains substantial dark areas, but it doesn't automatically mean the image is underexposed.
What does the right side of a histogram represent?
The right side represents the brightest tones, including highlights and whites. If the graph reaches the far-right edge, some pixels may be clipped and lose detail.
Should I use the RGB histogram or luminance histogram?
Both are useful. A luminance histogram is best for evaluating general brightness and exposure, while an RGB histogram helps identify individual color channels that may be clipping.
Is the histogram different for RAW and JPEG files?
Yes. Most camera histograms are based on a processed JPEG preview, even when shooting RAW. RAW files can retain additional highlight and shadow information beyond what the camera histogram displays, although recovery is not unlimited.
Can histograms help with landscape photography?
Yes. Histograms are especially useful for evaluating bright skies, dark foregrounds, and high dynamic range scenes. They can help determine whether a single exposure is sufficient or whether exposure bracketing may be necessary.
Can histograms help with concert photography?
Yes. They help photographers evaluate exposure in difficult stage lighting, monitor important highlights, and identify potential color channel clipping. They are particularly useful when performers are illuminated by intense colored lights.
Why does my photo look fine but the histogram looks wrong?
A histogram doesn't understand the subject or creative intent. A photograph containing mostly dark or bright tones may be correctly exposed even if the graph looks heavily weighted to one side. Evaluate the histogram alongside the actual image rather than treating it as a pass-or-fail test.
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