We have a flat paint we love and wanted to paint the ceiling the exact color. Even though it's flat, it has more sheen than we'd like for a ceiling paint.
I've done a bit of research and have several ideas:
rough up the whole surface with 500grit sandpaper or steel wool
DIY powder additives like diatomaceous earth or calcium carbonate
additives that aren't made for reducing sheen but evidently tend to, like EmulsaBond or Floetrol
attempt to remove some paint with vinegar or hand sanitizer and hope it keeps color and reduces sheen
TSP or a liquid deglosser (I actually already have Jasco "easy liquid sander deglosser" from another project)
Any of these sound plausible? All terrible? Any other suggestions?
(It's HGTV Sherwin Williams paint from Lowes if that makes a difference.) I wish they tinted ceiling paint (assuming it's a truer flat/matte) .. but even then my "gallon" of regular flat is not quite a gallon, and the SW ceiling paint is, so even if I got someone to agree to hack the tint, it wouldn't tint the exact same.
What makes us not like the flat paint as is? It's not as flat as whatever the builders used, and with the texture it makes the ceiling appear polka dotted when looking across the room. Plus, we had a repair, and the slight sheen makes it appear obvious. We thought about just going with standard white ceiling paint, but it makes the room feel a bit choppy.