Hi guys, need help! Fast Framestone, slow storage. Render artifacts (black masks, etc.). Weak NAS or config issue? Running A4500 20GB GPU, latest
DKU.
DKU.
Noting that it’s a 1600-frame sequence in 5K DPX.
What colour space are you working in?
Log dpx 12bits
Looks like some extreme values in a matte or two mattes being combined via a subtract. Is either of those things happening?
Yeah, first place I’d start is with a clamp on my masks
Not saying this is the OP’s problem, but…
If you need a clamp, you probably did something wrong.
If you negate, then multiply a matte instead of subtracting, you’ll never have negative values.
Also try screening instead of adding when combining to keep the values from going over 1.
Better edges are a bonus benefit to these simple techniques.
It’s really compositing 101. Shocking how many flame artists don’t have these basic skills.
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It does look like a NAN issue to me too, where there is some maths going on that has produced a negative number. Harder to do in Log than in linear but still possible.
You want to look through your comp. In a lot of nodes there is an ability to clamp within it instead of adding a clamp node but as Sam suggests, this is a quick fix to correct something. That hasn’t been done properly.
Also make sure that none of your footage has been tagged incorrectly in regards to colour space.
@Fernandovfx - Foi uma sessĂŁo super divertida, irmĂŁo - vamos fazer mais!
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I agree it looks like negative values, probably from a comp node set to subtract. If I’m just gmasking out a portion of an existing matte, I do it right in the gmask node with the mask set to outside.
I’m an unapologetic disciple of the negate multiply and also the screen methods of combining mattes. I believe I learned it in one of your flame FxPHds a decade ago @SamE!
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Sorry to jump on your shit @BrittCiampa.
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@BrittCiampa @SamE I love and respect you both, but may I suggest you combine mattes with the comp node’s blue inputs? 
It’ll do the invert and multiply, the screen, and every other option you could want, all in a single node! I highly recommend.
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And if the above don’t fix it,… I’ve seen similar results caused by mblur, try rendering with mblur off in your masks and/or action nodes, … if that works then you need to do some prerenders with mblur on or mblur workarounds ie RSMB, …
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Hey @andy_dill, Can you use just the blue inputs? I never tried it…
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I do it all the time, but you have to remember to hit f4 twice because you’re looking at the matte output. Hitting it just once shows black.
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Apologies for not recalling this specific lesson. I have the FXPHD video tutorials and would appreciate guidance on which one covers this topic. Thank you for bringing it to my attention