how to brush a picture like this in photoshop?

[Maria Atelier]

Hello, as a Photoshop beginner, I am facing an exciting challenge. I'm an analogue artist, but now I have to make a digital template for sandblasting a glass surface. The glass should not be completely frosted, that would be too boring. The aim is to create a picture that is composed of nothing but small "grains". The technical procedure is as follows: The template consists of shades of gray. The greyer the tones, the more frosted the glass will be. So I have to make a very nice, fine grain in Photoshop, which is transferred to the glass on a scale of 1:1. So every pixel value is transferred to the glass. My question now is, how can I realize this image that I have attached in Photoshop under the conditions mentioned? I would really appreciate your feedback. Thank you very much for your patience.

[Maria Atelier]

Additionally I've designed a picture. I would like to transfer this materiality (right side, blue arrow) into Photoshop: as if something were painted on fine plaster.

[Lumigraphics]

How does this translate to airbrushing? You say "transferred to the glass" so please explain how that happens.

[Maria Atelier]

Thank you very much for the inquiry! The image I create digitally is transferred to glass through an etching technique. This means that the gray tones of the image make it clear how much the glass is etched. The blacker a value in the image, the whiter the glass becomes, i.e. it becomes increasingly opaque. However, it is important that the image itself does not have a homogeneous surface in Photoshop, but appears very slightly roughened, i.e. as if on very fine plaster. If the glass is evenly etched, then it also looks like a shield at a bank counter or at the doctor's. So I have to take into account in Photoshop that there is always a very fine structure (see picture). How do I do this? I am grateful for your help.I work with brushes, but I can't get a very fine grain. E.g. the Kyle brushes are way too coarse. It would have to be an effect similar to that of very fine frescoes. Thank you very much for your time!

[Lumigraphics]

Have tou tried adding noise?

[c.pfaffenbichler]

A Noise based on 50% gray in a Pattern Layer with an appropriate Blend Mode might help.