PL8: The new Tone Curve - - Discoveries and learnings

[John-M (Melbourne, Australia - Win10)]

@John-M

… using the Gamma slider on the Luma channel alone should be a simple and effective means of “brightening” under-exposed images whilst protecting highlights and colours.

@John-M

I’m not yet convinced, tho, that this is working as effectively in practice as it sounds in theory

I used the 16 million colors 16-bit TIFF provided by @Wlodek (See above) to test this speculation … and confirmed that the Gamma slider on the Luma channel does do a better job of “brightening” an image - c/w using the Gamma slider on the RGB channel.

• I created a VC of the image, and applied Tone Curve = “Linear” for both the (M)aster and the VC versions … then;

• For the (M)aster version, I set the Gamma slider = 2.5 on the RGB channel - - and the Gamma slider = 1.0 on the Luma channel.

• For the VC version, I applied the opposite settings … setting the Gamma slider = 1.0 on the RGB channel - - and the Gamma slider = 2.5 on the Luma channel.

• Then, using the Compare button, I checked the result on both versions … to find much better colour retention for the VC version - whilst achieving “just-as-good” brightening (according to my eye) to what was achieved for the (M)aster version.