colour.models.log_decoding_Log2#

colour.models.log_decoding_Log2(log_norm: ArrayLike, middle_grey: float = 0.18, min_exposure: float = -6.5, max_exposure: float = 6.5) → NDArrayFloat[source]#

Define the common Log2 decoding function.

Parameters:

  • log_norm (ArrayLike) – Logarithmic data to undergo decoding.

  • middle_grey (float) – Middle Grey exposure value.

  • min_exposure (float) – Minimum exposure level.

  • max_exposure (float) – Maximum exposure level.

Returns:

Linear Log2 decoded data.

Return type:

numpy.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

[TheAoMPAaSciencesScienceaTCouncilAcademyCESACESPSubcommitteec]

Examples

>>> log_decoding_Log2(0.5)  
0.1799999...