In reading about the Hue blend mode, I have come to understand (perhaps erroneously) that given two layers (T)op and (B)ottom, that if the Blend Mode of T is set to Hue, then the hue information in T will be blended with the saturation and luminosity in B, which essentially means that the hue information in B is replaced by the hue information in T. However, in running some experiments, I've noticed that when dealing with a very simple document comprised of two layers only, that setting the Blend Mode to Hue also changes the saturation and brightness.
Here are the steps to duplicate the observed phenomena using two regular layers:
And here are the steps to duplicate the observed phenomena using a regular layer and an adjustment layer:
The results in both (for me) are identical. Am I misunderstanding the Hue blend mode?
Photoshop Info: 13.0.1 x64 Extended
OS: Windows 7 64-bit
CPU: Dual Xeon E5440
RAM: 16 GB
Video: Nvidia GeForce GTX-580
The blending happens in an HSL model.
You're making measurements in an HSB model.
Also, changing the hue while preserving lightness and saturation sometimes would result in illegal values - and those have to be clipped back to valid values (while preserving the hue). This will result in changes to lightness or saturation.
Thanks very much for your straightforward and helpful answer. So, it would appear that my simplistic understanding of the Hue blend mode as 'replacing' the hue of the underlying layer(s) is incorrect. Would a fair rendering of what the Hue blend mode actually does be as follows?
"The Hue blend mode will perform a direct replacement of the hue in the underlying layer(s). The brightness and saturation of the underlying layer(s) will not be affected *unless* the resultant hue, saturation, and brightness 3-tuple would result in an illegal HSL combination, in which case the saturation and brightness of the resultant pixels will be altered to bring the HSL values into compliance."
Also, is there a way for the Info panel to display HSL values?