Acorn Acorn 6

Color Adjustment Filters

Many of the filter definitions below come directly from Apple’s core image filter reference. 

1bit:  Converts all pixels in your image to either black or white.

Alpha Multiply:  Multiplies the alpha values of your pixels by a certain amount.  Can be useful for sharpening anti-aliased edges of shapes and text.

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Original image

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Color Controls: Brightness decreased

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Color Controls:  Saturation increased

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Color Controls: Saturation decreased

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Exposure Adjust: Exposure decreased

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Gamma Adjust:  Power decreased



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Hue Adjust

Color Controls:  Adjusts saturation, brightness, and contrast values.

Curves: See Curves.

Dither:   Dither your layer with a drop down menu to choose from Atkinson (old school Mac OS), Floyd Steinberg, Gaussian Blue, and Ordered Reproducible.  

Exposure Adjust:  Adjusts the exposure setting for an image similar to the way you control exposure for a camera when you change the F-stop.  This filter multiplies the color values to simulate exposure change by the specified F-stops.

Gamma Adjust:  Adjusts midtone brightness.  This filter is typically used to compensate for nonlinear effects of displays.  Adjusting the gamma effectively changes the slop of the transition between black and white.  

Grayscale:  Turns a colored image into grayscale.  See Black & White.

Hue Adjust:  Changes the overall hue, or tint, of the source pixels.  This filter essentially rotates the color cube around the neutral axis.

Levels:  See Levels.

Remove Color Cast: Adjust the exposure and choose a color to remove in your image to be replaced with white.  This is useful for images taken indoors that are excessively yellow.  

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Remove Color Cast Filter

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Replace Color:  Choose a specific color to remove and replace it with another.  Adjust the tolerance as needed.

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Transparentomatic: Remove a specific color in your image and replace it with transparency.



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Vibrance: Adjusts the saturation of an image while keeping pleasing skin tones.

White Point Adjust: Adjusts the reference white point for an image and maps all colors in the source using the new reference.




Vibrance increased

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White point adjust to a gray/blue

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Try playing around with some of the filters and experiment, experiment, experiment.  For more information, check out the Tutorials or send an email to and request a tutorial.

Additional Relevant Documentation  

Filters Basics (video tutorial)

Filters Basics

Color Adjustment