Just because everyone does it or just because everyone wants it, doesn't improve the actual quality of what is being done. Pretty much every vendor that sells eye colour textures adds a reflection component: fake reflections. This is added because all the customers want it. The customer doesn't know any better, and the vendor is happy to comply because that is what generate sales. Whether it is right or not is immaterial. Along comes a dufus like me who wants a non fake reflection eye colour, and I get weird responses from vendors asking why the heck I would want that. When I explain that the super-imposed reflections they put on it interferes with my scene lights based reflections, they quickly dump me in the too-hard basket and ignore me.

This has happened too often. Wrong becomes right through frequency.

Here in Oz, we have a substance called Bactrim. It is a sulfonamide, also known as a sulfa drug. Because "UR" is pronounced "AH" here, dim-witted clerks writing drug allergies on patients charts are interpreting the sound to an element: "Sulphur". Whilst there are some sulphur atoms in these drugs, there are a lot of other element atoms as well. The words may sound alike but this doesn't mean they are the same nor that there are cross-reactivities to allergens.

Despite the fact that this is true, because everyone with this on their charts believes they are allergic the "suphur"... sheesh, what do you do? Educate a nation?? :rolleyes:

Economics drives the quality of what we receive from vendors, large and small. Whether we want to take this to the next step is up to us. Me, I'd rather not settle for the lowest common denominator. If you want to do like everyone else, sheesh, look at their work and copy it. That's not hard to do. There's heaps of "tutorials" out there on how to achieve that "quality" of work.

If a lesson on how to use CS4 was all the OP wanted, well, okay, fair enough. I guess we didn't actually answer the original question:

Quote - I have photoshop cs4 and can simply take the v4 skin map load it and then in photoshop desaturate it and it becomes a grey scale, but this process seems not dark enough compared to other bump maps I have purchased for V4. I am trying to make my own skin. Is there something I should be doing to the desaturated map once I make it?

Anyone care to answer that question? I don't.

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks