Proper usage of VRayAlpha in Photoshop CC

[Art48]

Hi,

So how do I use the VRayAlpha element in Photoshop CC without getting fringes? I usually render on black and use the integrated Alpha of the EXR, I was just wondering if there is a way to properly use the VRayAlpha without getting fringes.

[Joelaff]

I have not tried it, but likely this is just a result of the image being premultiplied with black.

Load the alpha selection. Float that to a new layer (new layer via copy). Hide the underlying (original) layer, or delete it. Select the layer you just floated with the selection, which will have a slight black fringe. Make sure you have nothing selected, and go to Layer->Matting_>Remove Black Matte.

This is the old way to unmultiply an image in Photoshop, before PS started supporting and interpreting some alpha as what it calls "Layer Transparency."

[Art48]

Holy sh** I totally forgot about those layer options! Mainly because in the german version of Photoshop the naming of those functions are just awful. But it worked as expected.
I copied my alpha into a mask for the RGB Layer, applied the mask, then did the Remove Black Matte thing.