Use the Histogram panel

The Histogram panel shows how pixels are distributed across tonal values, helping you evaluate image quality and make accurate corrections.

Use the Histogram panel to assess tonal range, identify clipped shadows or highlights, and monitor adjustments in real time. The panel provides multiple view modes, channel options, and statistical data. To inspect specific pixel color values, use the Info panel with the Eyedropper and Color Sampler tools.

Understanding histogram displays

A histogram graphs the number of pixels at each intensity level. The left side represents shadows, the center shows midtones, and the right side displays highlights. The histogram shape reveals the tonal distribution of your image:

• Low-key images contain more shadow detail and appear weighted to the left.
• High-key images contain more highlight detail and appear weighted to the right.
• Average-key images concentrate detail in the midtone range.
• Images with a full tonal range show pixel distribution across the entire histogram.

Pixels grouped at either edge indicate clipping, which causes loss of detail in shadows or highlights. Images with a full tonal range generally provide greater editing flexibility.

For RGB and CMYK images, the histogram displays overlapping color channels. Areas where all channels overlap appear white, while two-channel overlaps appear as cyan, magenta, or yellow.

Open and configure the panel view

The panel retains your channel selection when switching between Expanded View and All Channels View.

Select channels to display

In All Channels View, the Channel drop-down menu controls only the top histogram display.

Display channels in color

In Expanded View or All Channels View, select the panel menu, and then select Show Channels in Color.

When enabled, individual channels appear in their respective colors. If you select a single channel from the Channel drop-down menu with this option active, that channel displays in color even when switching to Compact View. Similarly, choosing Colors from the Channel drop-down menu displays the composite histogram in color across all views.

Channels display in their respective colors. If you select a single channel from the Channel drop-down menu, that channel remains colorized even in Compact View. Selecting Colors from the Channel drop-down menu displays the composite histogram in color across all views.

View histogram statistics

Select a source for multilayer documents

In Expanded View, select the Source drop-down menu, and then choose the histogram source as needed for evaluation.

Preview adjustment effects

In the Adjustment dialog box, open any color or tonal, and select the Preview option.

The Histogram panel updates in real time to show how adjustments affect tonal distribution. When using adjustment layers in the Adjustments panel, changes appear automatically without requiring a Preview option.

The panel overlays the original and adjusted histograms, making tonal shifts easy to compare.

Refresh cached histogram data

When a histogram is generated from cached data instead of the current image state, the Cached Data Warning icon appears in the Histogram panel. Cached histograms render faster by sampling representative pixels based on the current zoom level. Cache levels range from 1, which uses all image pixels, to 8, which prioritizes faster rendering by sampling more pixels. Higher cache settings improve performance for large multilayer files but require more RAM.

Select the panel menu, and then select the Uncached Refresh option, or double-click anywhere in the histogram.

You can adjust the maximum cache level in Edit > Preferences > Performance (Windows) or Photoshop > Settings > Performance (macOS). Use lower cache levels if working primarily with smaller images or if system RAM is limited.