Just color your taskbar images and adjust their opacity in an image editor.
Check out Taskbar image locations in my Taskbar maps in Tutorials section.
Watch my Beginners video in Tips & Tricks section.
You can adjust opacity in Gimp for instance using the Opacity Slider in the Layers dialogue.
Is it really that simple?? I thought (probably wrongly) that the taskbar or any other image that adjustments could be made to, had to be "lacking colour". As in, a Photoshop, I have PS5 (Chrimble prezzy off SWMBO!!, so after all them ££££ I don't want to use GIMP!!), anyway a PS5 layer mask is black to white, you don't see the black, you see the white, it affects what you do see. Please accept my ignorance, I'm new to this.
As an example, the bog standard taskbar (msstyles #'s 839 & 840) were a white (1 pixel) square highlight, a very dark low light above, and the actual bits I would call the taskbar were a mid to dark neutral tapering to nearly nothing. So, the more "BLACK" I can see, the less the desktop can see. Did I get that right?
Also, if I made a pea-soup green task bar, I believe, no matter what I do in the Personalise Window it will always be Pea green? (Now that is a daft Q, Elmer, you
know that answer!). I apologise for what may seem like totally "eejit" questions to you, but if I know the basics (for definite) the less winky questions will appear down the road!!
And Thanks 3am for your original answer.
Elmer