Edges — OZONE Asylum, home of the Mad Scientists

Edges

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Your Text: Insert Slimies » Insert UBB Code » Close Last Tag \| All Tags UBB Help	LaPlace Find Edges is Sobel with a few small steps thrown in. In particular, Pythagoras and invert. No big deal. However, Find Edges has a radius of 1. That's fine, but sometimes you might want a little extra width in certain places in your edges. This is where LaPlace and High Pass come in. Difference at a distance. Frequency. Yippie. I've heard folks talk about it before, even myself in that one blur thread by Klaatu. But I don't think anyone has really given explicit instructions. If someone has, I missed it. Fairly simple to figure out with a few hints, but I'm gonna give it up in case you've never heard or fiddled with it. - Random photograph - copy to new layer - Filter > Other > High Pass to taste - Edit > Fill --- Using: 50% Grey --- Mode: Difference That's about it. Now all you have to do is use your prefered method to desaturate and whatever. Use some of the ChOps talked about above. Invert it and junk. Two things to point out about High Pass. The first is that things are done from 128. The difference from there should never yield any values greater than 128. After Fill > Difference, check the Histogram and you'll see what I mean. Easy enough to tweak with Levels or Curves, but getting too extreme will probably bring out compression artifacts. The other thing is what happens at the center of the difference. You'll get like a locus of nothing where the difference crosses the event horizon. Maybe someone with a superior venacular and classical mathematitional edumacation can explains much betterer. That event horizon or crossing over is why I recommend complimenting High Pass with Find Edges. It's usually a good idea to fill in the Valley of Zero Point. Or not. I don't know for sure for you when you are doing your thing. A lot of the tips that I talked about with Find Edges also apply here. With some practice, you should be able to see what you need and go straight for the jugular. Or maybe come up with a general all-purpose technique that quenches your thirst most of the time. Or maybe pick up a little nugget and apply to something entirely different from edging. Or maybe you already have an all-purpose edging technique and don't wish to learn anything from this. Egads! Hahaha. Too funny. I'm not sure if I'm going to go any further from here. I might drop a few more notes as they strike me. Maybe answer some questions if they come. Refine a few things. Maybe show a few case studies. Just don't know right now. Until then, be the guru. play.fiddle.learn Loading...
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