pog
Premium
join:2004-06-03
Kihei, HI
 ·Hawaiian Telcom
| reply to pog
Re: [FYI] Pog's Color Filtrator v.032 alpha...
Instead of adding a bunch of things, like hue shift, etc... I decided to see if masking would work. It takes a fine touch to avoid a lot of harsh fringing... but I figure having a mask would open up a lot more doors already available in most editors. It will also make it easy to select multiple colors... just run the filter on duplicate layers.
Also added a cross hair for the cursor during selection in the preview. The selection occurs when the right button is released.
original test image
I used this image in testing... a bit better than a random photo which may or may not have as many colors, etc.
isolate a specific blue
- I right clicked on the blue square which sets mean hue, mean saturation and mean lightness.
- I wanted a narrower tolerance for hue, so I lowered the hue range. Hue is measured in degrees but for simplicity I have the control go from 0.000 to 1.000. It's the same as 0-360 degrees.
- a range of "1.000" more than covers the entire range available and I wanted to select only blues that were highly saturated. The saturation sliders above mean "select pixels that have a saturation of 73.6% to 100%"
- the lightness selection means 0.572 +/-0.027. In most (all?) spaces with a Lightness channel, it's important to know that 100% lightness is out of gamut if there's any color. 100% lightness in RGB works out to white.
- most of all, this is really more vision-based selection than calculation.
mask a specific blue
- This is the same as before but I clicked the "mask" checkbox. This can't work unless you're on a layer that has an alpha channel. A message box pops up if there's a problem.
- The blend slider turns into a "gain" slider. Transparency needs to be a bit harsher sometimes, so the gain slider can help with this. It's linear and the results can be severe at full strength (jagged, etc).
inverse mask a specific blue
- this is the same as above, except the effect slider has moved all the way to the left.
- note that the result is not the exact opposite. I'd like it to be... maybe I will figure out where I goofed. Probably with the "gain".
mask specific saturation
- setting the ranges for hue and lightness allows me to select based on saturation. The settings for saturation say "select pixels that have 0-2.7% saturation". Sometimes, what we see as pure gray is not perfectly gray and has some saturation in it.
- note how harsh the selection is... this is the gain ramped up high, mostly.
isolate specific range of green
- here, more seriously, I want to isolate a certain set of greens. It's pretty smooth IMO... output below.
isolate specific range of green output
 pog_color_fi···lpha.zip 98765 bytes
zipped 8bf plugin
download the filter here. The instructions are the same as the original post. Have fun!
Don't forget to post your before/after shots... I'd love to see them! 
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altermatt
Premium
join:2004-01-22
White Plains, NY
·Verizon Online DSL
1 edit | Incredible work, pog; as always, thanks. I particularly appreciate the "tutorials"; I'm still using some of your other filters at default settings because I'm a tad unsure about what everything does .
And fabulous examples, everyone. Can't wait to play.
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The truth of a thing is the feel of it, not the think of it. -- Stanley Kubrick |
