I agree with the SW man. I have no idea what you are painting, but it is important to sand the primer, clean it well with a tack rag or vacuum as the case may be and then slightly wash with plain water, and allow to dry thoroughly before a second coat, but I am not a professional, just someone who likes to paint anything that will not move.

Well blow me down. I thought I was the most anal for detail DIY painter on the planet, and I have not done this. No way man. Enough already.

My walls look beautiful by the way. But my DH sanded the plaster or whatever it is to perfection before I primed and painted. I can see where this extra step would make a good paint job even better tho.

Maybe in another lifetime.

Ivette

Very much so especially with new drywall. The paper adjoining taped joints will fuzz up a little, the primer permits these fibers to be sanded off. Then wipe down, I never use anything more than a swiffer or microfiber for this step.
With old work, it's nice to be able to get the nerds left over from the primer bucket so they aren't part of the character of the room forever.
If you used oil primer and a roller, you need to sand to knock down the little fibers from the roller cover that seem to emerge when using oil paint. (tip- try used but well-washed latex rollers for your next oil-primer job. they are fuzz-free)
Casey

Sanding will make the wall surface smooth. However, the next step may eliminate that if you choose poor quality roller covers and paint.

Use a lambs wool roller cover and the highest quality paint you can afford. Follow application instructions to ensure a smooth, beautiful finish.

For a smooth finish (no stipple), choose Muralo Ultra Ceramic or BM Regal Matte.

Michael