Quote - I was referring to another formula, something other than:
linear = sRGB * 2.2
** do diffuse calculations
corrected = diffuse * (1/2.2)

The formula is not my own so I'm not at liberty to publish it, but it has been discussed on this forum, as I'm sure you're aware.

I'm not aware of a 'secret formula' but I'd be fascinated to know what it is. The formulae to apply and reverse sRGB's gamma functions are in the public domain. They were developed, along with the rest of the sRGB standard specification, by Microsoft, HP and Kodak and have been around for over 10 years. There's a complicated version and a simple version, both produce almost identical results under standard conditions.

There's simply no need for something else.

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