Rendering multi-layer EXR leaves small gaps between layers I know this is kinda a hybrid issue, but I think the problem here lies mostly with Blender.

I've rendered a multi-layered EXR file of a character I did in Blender to color and adjust it further in Photoshop. Arms, legs, head and so on are all on separate layers for easier access.

But as you can see in this picture, there are very thin gaps between each layer of like 1 pixel. Sadly they are visible even from afar and make the image look ugly.



Is there a way in Blender to circumvent this? I know this is a very specific question, but maybe someone has an idea.
This appears to be a problem with a misunderstanding as to how to handle alpha.

When pushing out alpha, raytracing engines use associated alpha, as only associated alpha represents both occlusion and emission.

As a result, the alpha in those subpixel seams must not be composited using the standard compositing operation, but rather one of the alternate over operations. Proper imaging tools such as Nuke offer the correct set of over functionality where anachronistic applications such as Photoshop do not. See for example, disjoint over.

When you have two pieces of geometry that share a subpixel but do not overlap, such as two angled bits of geometry that are perfectly flush with each other, the proper alpha combination amounts to an add. Do not use Photoshop's broken assumptions.

The best news is that this is purely the tip of the iceberg regarding Photoshop mishandling of proper EXR based work. Being display referred by design, it will fail miserably on many fronts including bit depth and proper scene referred data will be a nightmare.

See also this question which has more examples and a fleshed out solution with more depth.