Hue/Saturation error?

[pixel8tor]

When I open the Hue/Saturation dialog, before I enter any adjustments, Photoline is making an adjustment. I can see it if I have the Histogram window open. It creates a sharp cut at the mid-tone point, and moves the right side of the histogram to the right one step/tone. If I repeat this several times it becomes more obvious. Can anyone else reproduce this? It's been bothering me for a long time, because if that's really happening it's a destructive adjustment that can severely impact highlights. Thanks for any feedback on this issue.

HueSatBug.jpg

[Herbert123]

I can confirm this.

Furthermore, I copied the image layer and parented the hue/saturation adjustment to that copy and set the layer blend mode to DIfference.

The resulting histogram changes when I switch the adjustment layer on and off.

A mean deviation of 00.8, a standard one of 0.28

[Herbert123]

...and it's a real thing! Just to make sure it isn't a histogram or measuring error, I duplicated the adjustment twenty times, or so.

histo.jpg

[shijan]

Seems this happens only in 8-bit images.
Same problem also happens with Hue Editor, Selective Color Correction, Channel Mixer

[bkh]

I can reproduce this with PL 24.0 and the current beta on macOS 14.1.1. Didn’t try Seems that the panel shifts all pixel values above 127 (?) one up. This is not limited to hue/saturation but also affects Hue Editor, Optimize HDR, Channel Mixer (and probably more). Seems to be a rounding error or similar.

[pixel8tor]

Thanks for confirming this bug. It's been a long standing issue. And it's also useful knowing what other adjustment tools are affected - thanks for investigating this bug further.

[pixel8tor]

This topic is continued here: viewtopic.php?f=3&t=7010