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Variable Frequency

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Your Text: Insert Slimies » Insert UBB Code » Close Last Tag \| All Tags UBB Help	Variable Medium Did you warm up your noodle by trying the variable sharpening? I hope so. But even if you didn't, gonna forge ahead with variable medium. Even though this next example is about variable medium, gonna also do a bit of regular sharpening. Yes, mixing frequencies like this is possible. In order to get medium frequencies, you have to blur twice. Then you use the LL@50% thing to get the medium frequencies. To get variable medium frequencies, this means painting two different blur masks. Believe me, this isn't easy. Even though I've had this on my mind for a long time, this little conundrum has held me back from talking about these things. While I don't mind being mind-numbing, this is a bit too mind-numbing. Then, just the other day, I was doing some channel mixing. Then it occurred to me: why not paint both blur maps at the same time using RGB channels? Disco! R channel = BlurMask1 G channel = BlurMask2 B channel = whatever, 128 for me Just keep your colour palette open and set to RGB. Very easy to guesstimate the frequency work with 2 sliders sitting right there. When done painting your 2d blur mask, just copy both channels in the Channels palette and get busy with Lens Blur. In doing all of this, several different things can go in either direction. Invert one, and the result flips. Invert two things, and the results are back. Going to lay down some rules for this exercise. Going to be doing this Ghostbuster style. - Low frequency blurring gets a higher radius than high frequency blurring, or both get the same radii. I usually use the same radius for both Lens Blur steps. - When painting your blur mask, G can not be higher than R. Or, if you prefer, R must be equal to or greater than G. In other words, don't cross the streamers. When you do, you reverse the polarity. And since we are dealing with several different things, you can reverse the polarity several different times. Tasty, but not right now. Time for our image. Meet Panama Kid: [img]http://tech-slop.serveit.org/wiki/images/variablemedium01.jpg[/img] He's yet another shining example of good photographs that can be found on a cheap, royalty-free, stock photograph CD. The best $5 I've ever spend. Seriously. Looking that the photograph, I can see some different frequencies. PK's hair and his cat are high frequency. The background is a rather tight low frequency. His body has the lowest frequencies. With Colour palette open and armed with Paintbrush, time to think about what frequencies I want to enhance. Sharpen hair and cat: R = 48 G = 0 Since G=0, those number will pure sharpen. Medium body: R = 163 G = 69 This will enhance contrast without much sharpening at all. I guess you could say medium frequency right in the middle. Background: R = 255 G = 41 These number will enhance contrast and sharpen just a tad more than his body. Well, not really sharpen, but be tighter. Also be broader since R is maxed out. And topped off with a bit of Smudge tool: [img]http://tech-slop.serveit.org/wiki/images/variablemedium02.jpg[/img] Yeah, quick-n-sleazy. Okay, the more I want to blur, the higher the value of R. The higher the value of R, the lower the frequency. The more high frequency I want to subtract from the low frequency, the higher the G value. When G = 0, there is nothing to subtract. Can you guess what happens when R = G? I love this stuff. Once done painting, copy R and G in the Channels palette. Copy the photograph twice, and each get Lens Blur at the same radius using each channel in turn. Then it's off to do the LL@50% thing. And this is what I'm left with: [img]http://tech-slop.serveit.org/wiki/images/variablemedium03.jpg[/img] Look at PK's hair and his cat. Very tell-tale High Pass. But look at how much softer the background is in comparison. Oh, man. That is truly a thing of beauty. Just for fun, here he is with the final result set to LL@50% over the original: [img]http://tech-slop.serveit.org/wiki/images/variablemedium04.jpg[/img] Beautiful. After playing with it for a bit, and maybe recording an Action to help, start breaking the Ghostbusters' rule. You just might surprise yourself. That's about it for now. [img]http://cablespeed.com/~jlhalmich/ozone/koopaisgreater.gif[/img] Loading...
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