colour.models.log_decoding_Log2

colour.models.log_decoding_Log2(log_norm, middle_grey=0.18, min_exposure=- 6.5, max_exposure=6.5)[source]

Defines the common Log2 decoding function.

Parameters
  • log_norm (numeric or array_like) – Logarithmic data to undergo decoding.

  • middle_grey (numeric, optional) – Middle Grey exposure value.

  • min_exposure (numeric, optional) – Minimum exposure level.

  • max_exposure (numeric, optional) – Maximum exposure level.

Returns

Linear Log2 decoded data.

Return type

numeric or ndarray

Notes

  • The common Log2 decoding function can be used to build logarithmic to linear shapers in the ACES OCIO configuration.

  • The shaper with logarithmic encoded values can be decoded back to linear domain:

    Shaper Range

    Shaper Domain

    [0, 1]

    [0.002, 16.291]

References

[TheAoMPAaSciencesScienceaTCouncilAcademyCESACESPSubcommitteeb]

Examples

>>> log_decoding_Log2(0.5)  
0.1799999...