The Channel Saturation .8bf Plugin
Version 1.2, updated 3/14/2018

Plugin six channels

Channel Saturation (formerly Four Channel Saturation) allows you to adjust the chroma and vibrance of four or six opponent colors independently.

Four channel saturation is a simple parametric analog of L*a*b* curves, with a fixed center point so the white point does not change; but it uses the YCbCr color space with RGB images.  Six channel saturation uses the YCbCgCr color space, and divides the hue circle into six halves rather than four, with more resulting overlap.

A major difference between this type of saturation adjustment and the use of a Hue/Saturation layer is that this method may change the hue as well as the saturation.  It is useful for separating colors of low saturation, such as the tints of weathered wood; or closely-spaced colors, such as the greens of mixed foliage.

The lightness of each color may also be adjujsted.

The histogram is a saturation histogram.  White (background) is the original image; black (foreground) is the processed image.

Works with 8- or 16-bit RGB images.


Download the zipped file, then copy the plugin, the help file, and the demo registration key into your plugins folder.  The filter will appear under “RC Filters.” version 1.2, 439 KB, 64-bit applications. version 1.2, 435 KB, 32-bit applications, Windows 32 or 64 bit.

checksums | source code

MD5 Checksum: F8FEBCBDACB09726D3967145EAA0E514
SHA-256 Checksum: 085873D2BE26A1F8957A1CBB22269745B69F29157736D8788C280534A53E0E10
MD5 Checksum: 48C2B721EAB2DD08552E9D34D0738589
SHA-256 Checksum: 752D0F242BB83A9D2D9145AE3D777BA031F8152EE754CEB5F99A154F6101708B


The unregistered filters will save images up to 720 pixels in width and/or height.  Please purchase a registration key for $9.00 which unlocks all of the RC Filters.  Use the PayPal link below and I will e-mail you a text file (RCFKey.txt) to copy into your plugins folder.  Be sure to use a valid e-mail address (I don’t sell or give them away).  If you previously paid for any of the RC Filters, message me and I will send you a registration key.  The filters come with a demo key; if properly installed, the dialog will say “Demo key” when you click the About button.

The filters, the help files, and the registration key all go into the same folder.  It may help to make an RC Filters subfolder.  Each filter has a link back to the plugin folder on the About dialog for easy access.

© 2018 by Russell Cottrell; released under the GNU General Public License.
Updated 3/14/2018.