Primatte Help Needed

[user_deleted]

Hi

Id like to know if there is a trick for primatte to solve the hallow around the edges when I dont provide a background into the primatte.

ex: I key using primatte, and then put the keyed element in a over node.

It work perfectly when using keylight but I prefer primatte. And since using multiple matte is common when doing keying, there must be a way to correct this

Thanks for you help

Hugo

[user_deleted]

QUOTE(hugol @ 01/30/06, 02:19 PM) [snapback]226618[/snapback]
Id like to know if there is a trick for primatte to solve the hallow around the edges when I dont provide a background into the primatte.

are you talking about the blue spill or the dark rim?

in both ways, you can just color correct the foreground seperately, using a inverted, shrunk mask of the primatte as a mask input in your color correction mode.. then use a KeyMix.
for blue spill, HueCurves, SpillSupress and a Keylight (without using the mask) work well for me, but you could also use normal color correction nodes, such as Lookup or Mult.
for the dark rims, it's just a normal color correction... a Lookup or even an IAdd often helps.

btw, anybody got a more advanced method to do lightwraps with shake?
the lightwrap macro on this site didn't work too well for me.

++ chris

[user_deleted]

I always build them myself

ColorWheel1 = ColorWheel(720, 486, 1, 0, 1, 1, 1);
Grad1 = Grad(720, 486, 1, 0.5, 0.5, 1, 0, 0, 1, 0, 0, 1, 0, 1,
0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0);
Blur1 = Blur(ColorWheel1, 250, xPixels, 1, "gauss", xFilter,
"a");
Blur2 = Blur(Grad1, Blur1.xPixels, xPixels, 0, Blur1.xFilter,
Blur1.yFilter, "rgb");
Over1 = Over(ColorWheel1, Grad1, 1, 0, 0);
Outside1 = Outside(ColorWheel1, Blur1, 1);
KeyMix1 = KeyMix(Over1, Blur2, Outside1, 1, "A", 30, 0);

[user_deleted]

thanks, that works quite well..
i added a ContrastRGB on the alpha for some finer control of the edge area and built a macro with that. gonna upload it here if there's any interest once i did some more testing.

btw, did you raise the blur size of 250 for demonstration purposes or do you usually work with such high values?

++ christoph

[user_deleted]

depends on the size of the element being composited and what looks right. A blur value of 250 might be the maximum I would use for a medium shot. For a long shot obviously I would use smaller values. When I do a lightwrap on a person, I usually blur the matte enough so that there are no parts of the face that drop all the way to zero but there are on the body.

I think that a gamma might serve you better than a contrast RGB to tweak the matte.

You might want to add an edge blur to the macro too, i usually do these two steps one after another. I used to do a edge blur first followed by a light wrap, now I switched the order, I dont think it makes too much difference.

Checker1 = Checker(720, 576, 2, 32, xSize/GetDefaultAspect());
ColorWheel1 = ColorWheel(720, 576, 2, 0, 1, 1, 1);
EdgeDetect1 = EdgeDetect(ColorWheel1, 4, 0, 0, 0, 0, 0, 0, xBlur/GetDefaultAspect(),
0, xDilateErode/GetDefaultAspect(), 0, 0, "Fast", 8, 1);
Over1 = Over(ColorWheel1, Checker1, 1, 0, 0);
Blur1 = Blur(EdgeDetect1, 6, xPixels/GetDefaultAspect(), 0, "gauss",
xFilter, "rgba");
IBlur1 = IBlur(Over1, Blur1, 6, xPixels/GetDefaultAspect(), 0,
"gauss", xFilter, 5, 1, "A", "rgba", 0);

[user_deleted]

thanks for the clarifications...

you're probably right on the Gamma instead of the ContrastRGB... even though there's slightly less control this way you'd only have to use one slider instead of three (and hey, i always spend too much time on details nobody notices anyway

here's a first try for a combined macro - the inputs would be backround, foreground, and alpha (since it's really just a bumped up keymix). i used byte nodes to reduce the inputs... i also had to put in a SetDOD since i was getting weird results on the EdgeDetect if the alpha went out of frame.
last and not least, i switched the BlurApha_Var (your original Blur1) to "In Frame Only" for the same reason.

feel welcome to improve
++ christoph

BACKGROUND = Checker(720, 576, 2, 32, xSize/GetDefaultAspect());
Color1 = Color(720, 576, 1, 0, 1, red, 1, 0);
ColorWheel1 = ColorWheel(720, 610, 2, 0, 1, 1, 1);
Add1 = Add(ColorWheel1, -0.1, -0.3, 0.2, 0, 0);
MacroIn_BytesBG = Bytes(BACKGROUND, bytes);
BlurBG_Link = Blur(MacroIn_BytesBG, BlurAlpha_Var.xPixels, xPixels,
0, BlurAlpha_Var.xFilter, BlurAlpha_Var.yFilter, "rgb");
GREENSCREEN = Over(Add1, Color1, 1, 0, 0);
Keylight1 = Keylight(GREENSCREEN, 0, 0, 0, "1.4", "composite", 0,
1, 0.200000033, 0, 0.556, 0.9, 0.342, 0.2, 0.719, 0.524,
0.01055409, -0.675461769, 0, 0.4, 0.5, 0.5, 0.5, 1, rExposure,
rExposure, 1, rGamma, rGamma, 1, "linear", 1, "A", 1, "A",
0, 0);
ALPHA = DilateErode(Keylight1, "a", -1, xPixels/GetDefaultAspect(),
0, 0, 0);
MacroIn_BytesAlpha = Bytes(ALPHA, bytes);
BlurAlpha_Var = Blur(MacroIn_BytesAlpha, 100, xPixels, 0, "gauss",
xFilter, "a");
MacroIn_SwitchMatte = SwitchMatte(GREENSCREEN, MacroIn_BytesAlpha,
1, "A", 1, 0);
SetDOD1 = SetDOD(MacroIn_BytesAlpha, 0, width, 0, height);
EdgeDetect_Var = EdgeDetect(SetDOD1, 4, 0, 0, 0, 0, 0, 0, xBlur/GetDefaultAspect(),
0, xDilateErode/GetDefaultAspect(), 0, 0, "Fast", 8, MacroIn_BytesAlpha.bytes);
Outside1 = Outside(MacroIn_BytesAlpha, BlurAlpha_Var, 1);
Over = Over(MacroIn_SwitchMatte, MacroIn_BytesBG, 1, 0, 0);
Blur_Var = Blur(EdgeDetect_Var, 6, xPixels/GetDefaultAspect(),
0, "gauss", xFilter, "a");
Gamma_Var = Gamma(Outside1, 1, rGamma, rGamma, 1);
KeyMix_Var = KeyMix(Over, BlurBG_Link, Gamma_Var, 1, "A", 30,
0);
IBlur_Out = IBlur(KeyMix_Var, Blur_Var, 6, xPixels/GetDefaultAspect(),
0, "gauss", xFilter, 5, 1, "A", "rgba", 0);