The wall is mottled. What to do? New construction

Spotlight is just very ungrateful!

I can’t help myself, sorry! I would rather worry about window cleaning and changing light bulbs

Oh come on...

Painting is a bitch.

Everyone thinks I just paint the wall white.

Raking light is very ungrateful. What else could have happened:

- Paint too thick, uneven application
- Roller not "dipped" often enough, so at the end of the roller stroke too dry, uneven application see point 1
- Unevenly sanded surface, you yourself said the wall reacted differently to sanding (of course it wasn’t the fault of the person who sanded )
- Substrate itself not completely even, shadows

What could have been done? Let a professional handle it but even there are some for whom it probably would have looked like this. If you want it perfectly flat, you should use painter's fleece, but that in turn requires a perfect substrate.

What now? See answer

Edith: I don’t understand the hype about perfectly smooth walls anyway. It doesn’t have to be knockdown texture plaster but I prefer a little residual structure with 1mm grain size anyway.

I can't help myself, sorry! I would rather worry about cleaning the windows and changing the light bulbs

I will think about the light bulbs in 10 years, if maybe an LED breaks. We really wanted the window because we still want to take advantage of the light coming in and the window is also crucial for the exterior appearance (two windows side by side at the top on the Frisian gable). The window is cleaned once a year when the Christmas decorations are put up. The stair landing + ladder should allow this without any problems.

- Unevenly sanded surface, you said yourself the wall reacted differently to sanding (obviously it wasn't the fault of the person who sanded )

I sanded it. So only the wall can be to blame. When I saw the sanding marks, I asked a painter who said that it was quite normal. Honestly, I have never seen such strong marks on interior walls before. He just said that the paint would cover it again. But that is only partially the case.

Edit: I don't understand the hype about perfectly smooth walls anyway. It doesn't have to be trowel plaster but I prefer a slight residual texture with 1mm grain.

1mm grain is nice and all. But this rendering by the raking light is really annoying. The pictures can't even show it properly. Is there a special paint that handles raking light better? Our paint is white matte. Could that be the reason?

...well, okay, I'll put it this way... if you sand and paint as well as you photograph...

I'm not an expert either, I've just seen it many times before, during our previous renovations and at friends' places.

The only results I've seen so far without any "patchiness" were always walls and ceilings done by professionals and always with painter’s fleece. Mostly drywall. Those are already flat in themselves. If you have a brick wall and then the plasterer applies his interior plaster on it. No matter how good he is, he can't get it perfectly even like a drywall. And with the latter, for example, you see every little patch if it's not perfectly smoothed.
In raking light you barely have a chance. Hardly anyone gets upset about that.

Of course, it could look much worse in real life and just not be noticeable.

It would have been ideal if you had applied some filler over the unevenly sanded spots. You can always see that. It is also preferred to apply several thin layers rather than thick ones. Thickness is not a quality feature. The fillers smooth out the imperfections when going over them, but why should the compound fill in one spot and not in another. With a paint containing fillers, you can sand off a little bit. But I don't find it so terrible. Although I can paint, for example, at too high room temperature I have also produced terrible walls, the paint practically baked onto the wall. Everyone makes mistakes.

Best regards
Gabriele