Light Red and Dark Red shading on Not Selected Images

[KSNelson]

I am trying to find out what a further degree of shading of images in the Library View means beyond Most Selected, Selected, and Not Selected. I have two shades of Red labelling on pictures that are NOT selected.

[Rikk Flohr: Photography]

In or "not in" a Stack accounts for the multiple shades of color labels in images that are not Active or Selected

[KSNelson]

Aah! Thank you!

If an image is in a stack, it will be a darker shade of whatever color
label the image is.

Again, thank you.

Kent

[Rikk Flohr: Photography]

A reference chart: 

 

[KSNelson]

It's not Fifty Shades of Gray but merely four ...

Thanks again.