Paint.NET

This plugin extracts a color range from image, by leaving pixels of selected color opaque and making the rest transparent. Only alpha values are altered, color remains intact.
It is useful if you need to edit certain colors on your image separately: duplicate the image layer and run the plugin to get color-based "selection" for further editing.
It is more flexible than Magic Wand or Curves+ which could provide similar results but not always exactly as needed.
Menu location: Effects > Photo.
Download as part of my plugin pack.


Updated to version 2.2 (2008-12-24)!
Changes: few UI and code optimizations; moved to Color submenu.

Updated to version 2.1 (2008-08-31)!
- Compatibility fix for paint.net 3.36

Changes in v2 (2008-01-23):
- Effect is now located in Adjustments menu
- Added check box "Override Original Alpha" (see details below)
- Few minor bugfixes


Use the six color controls (on top) to define your color selection,
and three adjustment controls (on bottom) to adjust the output.
For ease of use, the default color range is defined around primary color. So I suggest to use color picker tool before starting the plugin.

Check box near each color control defines whether you restrict color by this parameter or not. Unchecking equals to selecting the full range.
Tolerance control makes alpha to fade off gradually, based on color's similarity to selected color. Max tolerance makes full alpha gradient from selected color to it's opposite (for example from full bright to full dark, if brightness from 255 to 255 is selected).
Feather control softens edges by blurring alpha channel by selected radius. I recommended to adjust this after all other controls are set, due to heavy impact on processing speed.
Base Opacity control adjusts alpha of "non-selected" color.
Invert Alpha check box inverts final alpha.
Override Original Alpha check box controls how to handle originally transparent/semitransparent pixels:
- unchecked (default) -> transparent pixels remain transparent, even if pixel's color match your selected color
- checked -> transparent pixels turn opaque if pixel's color match your selected color
Reset button returns to default setting (that is: color range from primary color and other controls zero).

Note: greyscale pixels are also treated as color, defined by Hue=0, Saturation=0.


Example:
here I attempted to extract skin tones from the photo. I started with color picker tool and clicked in the middle of his raised arm to get a good color sample. Then opened the plugin, adjusted the color range a bit, finally feathered by amount of 4. Screenshot:


You can learn the behaviour of this plugin on my test image, containing hue, saturation and brightness gradients:
link.

Tip: Feather, Base Opacity and Invert Alpha can be also used independently from color controls (with unchecked Hue/Sat/Brigh); so you may find alternative uses:
- Feather
- Base Opacity: to "un-erase" erased areas
- Invert Alpha: to invert opacity

Enjoy!

Awesome! Thanks!

quick note: I fixed a little UI appearance problem (related to win xp theme) about 10 minutes ago,
you may want to re-download (clean your browser cache before that).

Can you put it in either
Effects->Adjustment ?
or
Effects->Colors ?
or If you can think of a better place?
Thanks.

I couldn't make my mind on that, so I left it in Effects menu. Maybe I have better idea after some more user comments...

really nice

just a thing what about an UI like the Conditional Hue\Saturation?
you know with the color wheel to show the range..

oh yeah and Adjustments menu too, if you don't mind...

Thanks

This is really stinkin' cool, Tanel.

Yeah, what he said.






Finally, a way to cut out antialiased images fast*!

*Key word.

Wouldn't it be "Color" (without "s")?
(I just want to avoid to have two submenus with the same meaning.)

I don't care where this fine plugin is located, but I don't think it's an adjustment.

Tanel, nice update and great improvements from "Tone Picker", glad to see you took my advice and added the "feather" effect to your plug-in .

Geoff

I'm a fan of that color wheel - angle control too, but this is Evan's own creation and I don't want to rip off his code.

I tend to agree on Adjustments menu, seems to be more relevant than Effects. I will change it together with other possible fixes in a week or so.

Cool plugin, Tanel!

isn't that what open source is? something you can use to your own work by 'inspiration' from the work of others, without abusing it of course...

I don't think Conditional Hue and Saturation's source was released.

Yes it is, here: http://www.evanolds.com/pdnhs.html
But it is still quite over my head.