I am trying to get the depth value using z pass from my scene which is a simple head model, but while rendering there is white salt and pepper noise in the hair and eyelash. I have saved in both png after normalizing and in openexr file with the raw data. While looking into it I figure it out that both the object are using alpha value from the diffuse and opacity texture file. Below are the composite pass I am using -
Following is the node editor for hair/eyelash object -
Following are the image and corresponding depth (z pass output) as png in with the original alpha values -
Then I manually edited the alpha channel value in the texture image of the hair: I edited the alpha as 255 where there is a alpha value present ( > 0)
This reduced the noise a lot but at the same time its reduce the rendering quality of the hair mesh as well -
I have also tested with changing the max bounces for transparency and transmission but it did not change the result
Is there any further solution of this issue...
Blend File Link :