What does OpenEXR say deep images represent and how are deep IDs and subsample alpha meant to interchange between tools?
Splitting an OpenEXR deep sample recomputes alpha as 1-(1-alpha)^x, which equals un-premultiplying and re-premultiplying colour, with alpha 0 handled as a special case. Deep IDs store 32-bit or paired 64-bit hashes per sample (MurmurHash3 suggested, not required) with a manifest, keeping per-sample colour and alpha so isolated objects keep correct edges; Cryptomatte stores coverage only.
Splitting an OpenEXR deep sample recomputes alpha as 1-(1-alpha)^x, which equals un-premultiplying and re-premultiplying colour, with alpha 0 handled as a special case. Deep IDs store 32-bit or paired 64-bit hashes per sample (MurmurHash3 suggested, not required) with a manifest, keeping per-sample colour and alpha so isolated objects keep correct edges; Cryptomatte stores coverage only.
Curator qualifications: Specifications read 2026-10-22; no images composited.
Limitations: Specifications read 2026-10-22; no images composited.
Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.
Structured fields
{
"citations": [
{
"url": "https://github.com/AcademySoftwareFoundation/openexr/blob/dbdc101a3b754ee21f0e70ed28ffec1cba32c78e/website/TheoryDeepPixels.rst",
"note": "OpenEXR dbdc101a website/TheoryDeepPixels.rst L246, L298-L305; OpenEXR dbdc101a website/DeepIDsSpecification.rst L58-L77, L100-L101, L170-L177"
},
{
"url": "https://github.com/AcademySoftwareFoundation/openexr/blob/dbdc101a3b754ee21f0e70ed28ffec1cba32c78e/website/DeepIDsSpecification.rst",
"note": "OpenEXR dbdc101a website/TheoryDeepPixels.rst L246, L298-L305; OpenEXR dbdc101a website/DeepIDsSpecification.rst L58-L77, L100-L101, L170-L177"
}
]
}Evidence claims
- [sourced_fact] Splitting an OpenEXR deep sample recomputes alpha as 1-(1-alpha)^x, which equals un-premultiplying and re-premultiplying colour, with alpha 0 handled as a special case. Deep IDs store 32-bit or paired 64-bit hashes per sample (MurmurHash3 suggested, not required) with a manifest, keeping per-sample colour and alpha so isolated objects keep correct edges; Cryptomatte stores coverage only. · locator: OpenEXR dbdc101a website/TheoryDeepPixels.rst L246, L298-L305; OpenEXR dbdc101a website/DeepIDsSpecification.rst L58-L77, L100-L101, L170-L177 source
Rights
| component | license | hosting | redistribution | modification | training | Evidence and notes |
|---|---|---|---|---|---|---|
| documentation | unknown | permitted | permitted | unknown | unknown | Applies to this original summary only, not to the cited sources. |