Photoshop Elements >
Raw File Processing > 5
If you move a slider too far, the image is clipped.
That means it's underexposed or overexposed.
Histograms
First, a little orientation to histograms.
The histogram at the top right of the screen represents the number
of pixels in each brightness level.
Number of Pixels
The y-axis, the vertical axis, is the number of pixels.
Brightness Levels
The x-axis is the brightness levels.
There are 256 of them.
The brightness level of 0 denotes underexposure.
There's no image information there.
From 1 to 254, the brightness levels go from shadows to midtones
to highlights.
255 denotes overexposure.
There's no image information there.
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No Pixels: Underexposure
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Pixels: Shadows to Midtones to
Highlights
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No Pixels: Underexposure
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Color Channels
A photograph is composed of red, green, and blue channels.
These colors appear in the histogram.
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Red
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Red
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Green
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Green
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Blue
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Blue
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White
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All 3 Colors
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Cyan
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Blue + Green
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Magenta
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Red + Blue
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Yellow
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Red + Green
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Clipping
What Is It?
Clipping is when part of the image is underexposed or overexposed.
Think of a stained-glass window as if it's your photograph.
When the window is "well exposed," you can see the colors.
When the window is underexposed, it turns into a black hole.
There's nothing to see.
There are no pixels to edit.
Likewise, if the window is overexposed, it is like looking directly
at the sun.
There's nothing to see.
There are no pixels to edit.
So, a clipped area in an image is a pest.
You can't edit the area because there are no pixels to edit.
For example, portions of clouds are often clipped, overexposed.
You can't darken these areas with burning and dodging.
There are no pixels there to darken or lighten.
You have to paint these areas.
If you haven't already done so, go to
Painting
Overexposed Areas.
Clipping One, Two, or All, Color Channels
As mentioned, a photograph is composed of different combinations
of three color channels.
You can clip only one or two of these channels, or all three.
How to Tell if Clipping Is Present
There are four ways to identify clipping.
Method #1 - Spikes
If the image is clipped, a spike will appear on the left or right
edges of the histogram.
A spike on the left edge means a portion of the image is underexposed.
A right-edge spike denotes overexposure.
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Left Spike
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No Pixels: Underexposure
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Right Spike
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No Pixels: Overexposure
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Method #2 - Triangles
There's a triangle in each upper corner of the histogram that
changes color if clipping is present.
The shadow triangle, on the left, is black if there's no clipping.
The highlight triangle, on the right, is white if there's no
clipping.
If one of the triangles is colored, click it.
Shadow clipping, underexposure, shows as blue areas on the photograph.
Highlight clipping, overexposure, shows as red areas on the photograph.
Method #3 - Alt or Option Key
While using the Exposure, Recovery, or Blacks sliders, press
and hold Alt (Windows) or Option (Mac).
Here's a chart of what you'll see when you use the sliders while
pressing and holding Alt (Windows) or Option (Mac).
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Black: No Clipping
White or Colors: Clipping
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Black: No Clipping
White or Colors: Clipping
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White: No Clipping
Black or Colors: Clipping
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Method #4 - RGB Values
You can use the RGB values in the histogram to check for underexposed
or overexposed, clipped, areas.
Place the cursor over an area that may be clipped.
If any of the RGB values are 0 or 255, the area is clipped.
Prevent Clipping with Your Camera
When you're photographing, check the LCD screen after pressing
the shutter release.
Over- or underexposed areas will blink on many cameras.
If an area is small and unimportant, ignore the warning.
But, for example, if large portions of a sky are blinking, use
exposure compensation to reduce the amount of light reaching
the sensor.
Or, use a
two-stop
graduated neutral density filter.
You can also check for clipping by looking for left- or right-edge
spikes on the histogram on your camera.
