Is it possible to manually select the colour to work on with Hue-saturation? Say for example I want to change the hue or saturation of an orange whilst leaving the majority of reds and yellows unaffected, how do I do this? In Hue-Saturation I can only choose from the preset colours (and Master). Or is there another tool that would accomplish this? Thanks
I hope I’m interpreting your question correctly but is the Color Select tool not working for you?
https://docs.gimp.org/en/gimp-tool-by-color-select.html