Thank you Shailendra / Misho, nice to see other workflows.
Yeah thinking about it gamma correcting the grain matte will not mess with
white and black points, i'll give it a try.
I'd just gamma up/down the matte in step 3 (you keep the 0 and 1)
m.
On 02.07.2013 15:40, Shailendra Pandey wrote:
Hi Magno,
Thats a good question.
every time you composite a premultiplied image A over B
for pixels with alpha =1 you get A
for pixels with alpha =0 you get B
for pixels with 0<alpha<1
you are essentially creating new pixels which in a way are a weighted
average(based on the alpha) of the two input imagesNow if you remember
averaging can be used to reduce grain e.g.
spatial(blurs) or temporal(frameblend)
There are a few ways you can address the problem of soft grain on the
edges of your patch.
1. composite your patch with soft alpha on the plate without grain2.
accumulate all your mattes for grain in separate stream3. process your
matte for grain e.g. compress range say using white
point in a grade(alpha) node and check black/white clamp
4. Use this matte to add grain on your comp.
Hope that helps
Cheers
SHAILENDRA
On Tue, Jul 2, 2013 at 10:14 PM, Magno Borgo <li...@borgo.tv> wrote:
Looking for your experience/tips on the following situation:
Removal area/clean plate, regrained to match the background plate.
It has an alpha channel, blurred to smooth transition.
But when its composited Over the original plate (heavy grain), on
the semi-transparent alpha region the grain is faint because of the
blending.
Creating an edge detection mask and grading just the grain of the
cleanplate on the transition area is working (making it stronger),
just wondering about other tips/techniques on this situation.
--
Magno Borgo
Certified Nuke Trainer
www.boundaryvfx.com [1]
www.borgo.tv [2]
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Links:
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