Changes to the spektrafilm profiles and LUTs shipped in this folder
====================================================================

The spektrafilm profiles, filter data and LUTs in this folder are by Andrea
Volpato (https://github.com/andreavolpato/spektrafilm) and are licensed under
CC BY-SA 4.0; see SPEKTRAFILM_LICENSE.txt. This file records how Negs' copies
differ from upstream, as that license asks.

2026-10: updated to the upstream experimental branch, commit 28bf883

- profiles/: the colour and B&W profiles are verbatim copies of 28bf883's
  src/spektrafilm/data/profiles. Unchanged.
- filters/: the dichroic, heat-absorbing and lens-transmission data are
  verbatim copies of 28bf883's. Unchanged. neutral_print_filters.json is
  28bf883's with Negs-only entries added (below); upstream's entries are
  unchanged.
- luts/spectral_upsampling/: hanatos2025_irradiance_xy_tc.{npy,toml},
  arctic2026beta04_reflectance_xy_tc.{npy,toml},
  mallett2019_reflectance_xy_tc.{npy,toml} and
  hanatos_irradiance_xy_coeffs_250304.lut are verbatim copies of 28bf883's
  src/spektrafilm/data/luts/spectral_upsampling. Unchanged. Earlier Negs
  versions shipped the hanatos2025 table as irradiance_xy_tc.npy (same bytes)
  and the arctic2026alpha02 tables, which upstream has since removed.

Negs-only data, not from spektrafilm:

- profiles/kodak_trix400_d76_8min.json and
  profiles/ilford_mgrc_deluxe_grade2.json are new preparations from Kodak and
  Ilford datasheets, in spektrafilm's profile format. Sources and method:
  profile-sources/bw-expansion/README.md.
- filters/neutral_print_filters.json: entries for kodak_trix400_d76_8min on
  every colour paper under TH-KG3, derived with upstream's own solver
  (runtime/print_balance.solve_neutral_filter_shifts at 28bf883) by
  scripts/derive_neutral_print_filters.py, which first re-derives upstream's
  entries for Double-X and three colour negatives to check the method. B&W
  papers (kodak_2302, ilford_mgrc_deluxe_grade2) have no colour to balance,
  so they get no entries and keep the C0 M50 Y50 fallback.