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Sharpening and Blurring


2004-09-03 09:24:52 PM oddballgeek [TotalFark]
What sometimes works REALLY nice is a duplicated composite layer. then you run the high pass filter on that until you can see sharp edges, set the whole thing to overlay and play with the opacity. it's kinda like a sharpening layer adjustment that way.

2005-01-14 03:22:27 PM oddballgeek [TotalFark]
a quick guide to unsharp mask, because it really is the only sharpening tool you'll ever need - albeit an unintuitive one.

amount: a value between 1 and 500 to specify the degree of sharpening. higher values mean more pronounced effects. values between 25% and 50% are for subtle effects. values between 300-500% are over the top and hardly ever used. values between 50%-300% are moderate sharpening. don't be afraid to use high numbers, anything under 25% you'll have difficulty even seeing . if you don't know which value to use, use a small value and keep on pressing ctrl+f. applying a value of 25% four times in a row in technically different from using it once with 100%, but the differences are minor and neglectable. that way you can build up your value.

radius: this option determines the thickness of the sharpened edge. a sharpened edge is simply defined as increased contrast between two pixels. this simulates changing the focus in a camera. low values will produce crisp edges, high values produce thicker edges with more contrast throughout the whole image. if you are working with screen images (web images, what we do on fark), you want LOW values. 0.5 is usually what you want to go with. if that brings out weird little imperfections, undo and try a value of up to 1.0. any higher values really are only for printing 300dpi images, which doesn't apply to anything we do for fark. a simple formula is 0.1 pixels for every 15 dpi of final image resolution, which makes 0.5 right for nearly every picture you'll work on. for special effects, you can try values higher than 20, but that's just for dicking around, really.

threshold: this takes values between 0 and 255 and will tell PS how to recognize edges in the picture. the value indicates the numerical difference between the brightness values of two neighboring pixels that must occur before PS will sharpen it. so a low value sharpens a lot of pixels, a high value sharpens only obvious edges. if you think of a grayscale image sharpened with a threshold of 255, that would mean that only borders between complete black and complete white are sharpened, everything else is left alone. effectively, if you just wanna punch up a soft image, you should leave this at 0. but sometimes when you want to make certain features stand out, playing with the threshold can give you just the right effect.

there. thanks to deke and the bible, hope it helps.

Motion Blur

2004-07-22 09:28:53 PM cranberryzero [TotalFark]
One little cool trick with layer masks and gradients is making sort of gradiented blurring which works really well with stuff like moving cars and whatnot.

You switch to quickmask mode, make a b/w gradient along the object (let's say a car) that you're trying to blur and then switch back to regular mode. you'll notice a selection that's about half the shape of the blur you made. now blur the layer for real this time and it'll give you a gradiated blur, so the back part of your car would be really blurred and the front would be clear, with a nice gradient in between.

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