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Q
Using Color Aberration Control
Request
I would like to eliminate color fringing / chromatic aberration in JPEG and TIFF images.
Response
The Color Aberration Control feature in Capture NX can be used to reduce or eliminate
color fringing caused by lateral chromatic aberration.
Before
Cyan and red fringes are visible in
the boundaries of this image.
After
Color Aberration Control reduces color
fringing in the image so that it is no longer
noticeable.
The Before and After images above have been enlarged to make the effects of lateral
chromatic aberration more easily seen.
Procedures
Lateral chromatic aberration
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Light wavelengths differ depending upon color. Differences in the length of these wavelengths
result in changes in image magnification and become visible at image peripheries. This is known
as lateral chromatic aberration and is the cause of color fringing. Lateral chromatic aberration is
reduced to some degree by combining lens elements with different refractive indexes, but optically
speaking, it cannot be completely eliminated. In addition to red and its complementary color, cyan,
color fringing and blue and its complementary color, yellow, color fringing, some lenses may exhibit
complex color fringing that combines the two primary types.
The two illustrations below show how chromatic aberration typically appears. The illustration on the
left exhibits no chromatic aberration, while the image on the right shows what happens when
chromatic aberration (red and cyan color fringing) occurs. When chromatic aberration occurs, color
fringing becomes especially noticeable in portions of the image exhibiting high contrast.
No chromatic aberration
With chromatic aberration
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STEP 1: Enlarge image display so that lateral chromatic aberration is clearly visible
Open an image and select the Zoom Tool.
Click or drag the Zoom Tool over the portion of the image exhibiting chromatic
aberration.
Confirm chromatic aberration in the enlarged portion of the image. In the sample image,
we see red and cyan color fringing.
Cyan and red fringes are
visible in the boundaries of
this image. This is known
as “Red and Cyan”
chromatic aberration.
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STEP 2: Apply Color Aberration Correction and enhancement is complete
Select Color Aberration Control… from the Correct submenu in the Adjust menu.
Correct color fringing by dragging the Red—Cyan slider in the Color Aberration
Correction dialog to the left or right. Here we have moved the slider to the left (to a
value of -84 ).
Chromatic aberration is corrected.
Click OK .
A Color Aberration Correction step is added to the Edit List.
Color Aberration Correction slider operation
The Red—Cyan slider adjusts the red channel in a color (RGB) image to correct red and/or cyan
color fringing. Moving the slider to the left reduces red color fringing, while moving the slider to the
right reduces cyan color fringing.
The Blue—Yellow slider adjusts the blue channel in a color (RGB) image. Moving the slider to the
left reduces blue color fringing and moving the slider to the right reduces yellow color fringing.
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Chromatic aberration is
corrected so that color
fringing is no longer
noticeable.
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