Welcome to RC Filters!


Here is an overview of the plugins that I have made for Photoshop and compatible applications such as PhotoLine and IrfanView.  Each of them was made with specific goals in mind; I have pointed out the advantages of each plugin.  More information is available on the download pages.

Each filter is available in three versions:  64-bit for most 64-bit applications, 32-bit for 32-bit applications (running in either Windows 32 or 64 bit), and a “retro” 32-bit version compatible with Windows XP.  (Please note that IrfanView 64 bit uses only 32-bit filters.)

The filters were made with FilterMeister and run in Windows applications.  I have provided the source code for most of the filters and released them under the GNU General Public License; if someone wants to make Mac or Linux versions, that’s fine with me.

Can I run these filters on a Mac?  Or on Linux?



1.  Filters that I use on most images:


Fine USM Sharpen/Deblur

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Fine USM Sharpen/Deblur gives you full control over the unsharp masking and deconvolution processes, including luminosity mode, halo elimination, very high amounts, edge masking, and blend ranges.

Advantages:  dual-mode USM and deconvolution, halo control, and integrated edge masking.


Very High Radius Unsharp Mask


Plugin

High-radius low-amount (HiRaLoAm) unsharp masking is a technique for increasing local contrast, or “clarity.”  The radius is large compared to that used for conventional sharpening, often an appreciable fraction of the overall image dimensions.

Advantages:  the plugin is able to use radii of thousands of pixels for very large images.  Masking protects blown highlights and shadows.

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2.  Filters for enhancing certain images:


Adaptive Histogram EQ


Plugin

Histogram equalization attempts to evenly distribute values across an image’s histogram.  Unlike a simple levels adjustment, equalization tends to increase contrast in low-contrast areas, while doing the opposite in high-contrast areas.  Adaptive equalization samples the pixels in separate regions of the image and applies equalization locally.

Advantages:  smooth results; full color preservation.

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Adaptive Contrast Curve


Plugin

Adaptive Contrast Curve samples the pixels in separate regions of the image and applies a contrast curve centered on the local average.  It operates similarly to the Adaptive Histogram EQ filter, but uses an S-curve instead of histogram equalization.  It may be used to bring out texture or even create an embossed look.

Advantages:  smooth results; full control of the s-curve.  Masking protects blown highlights and shadows.

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3.  Color filters; I use one of these on most images:


The Ultimate Hue/Saturation Plugin


Plugin

The Ultimate Hue/Saturation Control adds a variable vibrance control to the familiar hue and saturation.  Adjustments may be made to up to six selectable color ranges as well as globally.  The adjustment takes place in the YCbCr color space and is a “smart saturation,” limited to the maximum for the color’s hue and luminance.

Advantages:  curve-like adjustment of the vibrance; “smart saturation” will not change the hue or block oversaturated colors; saturation histogram for feedback about the results.

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Four Channel Saturation


Plugin

Four Channel Saturation allows you to adjust the chroma and vibrance of the four opponent colors independently.  It is similar to using L*a*b* curves, but uses the YCbCr color space with RGB images.  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.

Advantages:  a simple parametric analog of L*a*b* curves, with a fixed center point so the white point does not change; global saturation and vibrance adjustments.

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Saturation Mask


Plugin

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Saturation Mask converts an image according to one of a number of color models and extracts the saturation or chroma channel.  It then inverts the extracted image and applies auto levels to fully expand the range from black to white.  Use the image as a mask to convert a hue/saturation control to a custom vibrance control.

Advantages:  unique.  This was my first Photoshop plugin.  I had made a similar plugin for ImageJ but wanted to do the same thing in Photoshop.



4.  Filters for special situations:


Very High Radius High Pass Contrast


Plugin

High-pass contrast enhancement requires two steps:  the creation of a high-pass filtered image, and the blending of this image with the original.  The Very High Radius High Pass Contrast filter gives you full control over the entire process.

Advantages:  able to use radii of thousands of pixels for very large images.  A number of different effects are possible depending on the choices made in each step.

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Retinex


Plugin

Retinex image processing attempts to imitate the lightness and color perception of human vision.  It is best suited for rescuing underexposed or badly color balanced images, or for extracting detail for scientific or technical purposes.

Advantages:  unique.  Intuitive interface; a high degree of control over the process.  Masking protects blown highlights and shadows.

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New as of 3/2/2017:


RG Color


Plugin

The RG or red-green color space is a color space that uses only two colors, red and green.  The plugin converts RGB images to RG, and facilitates a number of editing functions that may improve RG images, such as pre- and post-conversion saturation and hue adjustments, and two different image blends.

Advantages:  unique.  Selective red and green vibrance controls, hue limits, and a hue histogram.

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Can I run these filters on a Mac?  Or on Linux?

Yes, but you must do it in a Windows application.  PhotoLine is fully functional in Linux using Wine, and runs all the filters.  And I have now gotten it to work in OS X El Capitan using PhotoLine 19.51 and the Wine Development 1.9.17 package.  (Yes, I am an “inexperienced user.”)  IrfanView 32-bit does not install in Wine for some reason; and IrfanView 64-bit installs but does not run any .8bf filters.  Instructions for OS X:

•  Download and install the Wine Development .pkg file.  I also installed the mono and gecko packages as prompted.  Prerequisite:  XQuartz 2.7.7 or above; I used 2.7.9.

•  Run the PhotoLine installer (pl1951.exe) as usual.  After installation, the desktop links do not work; go to username/.wine/drive_c/Program Files/PhotoLine and create an alias to PhotoLine64.exe on the desktop.

•  Copy the 64-bit filters to the PhotoLine/Defaults/Plugins folder.  (And color profiles to the ICCProfiles folder if desired.)

•  Open the desktop alias with WineDevel.app, open an image, and run the filters (found under Filter — RC Filters).