I painted one wall of my kitchen with an almost-black flat paint. Rollers didn’t leave any marks, etc, but when I passed lightly my clean hand over the well-dried paint my fingers left light marks. I made it worse when I tried to slightly clean it with a soft cloth. Is dark paint so sensitive or should I put a protective coat of something (I don’t know what)?
This is typical of dark flat paint. You should repaint with a paint with a little sheen, egg shell or satin will work better.
An alternative is to use a clear acrylic finish, same clear coat used for wood finishing. But this might be difficult and a bit expensive to do.
Thank you, Karl for your answer.
In applying a coat of eggshell or another shining finish, is it possible to apply a clear/colorless finish? Painting with black paint is hard when making a straight line where wall meets ceiling.
A clear coat can be applied right over your existing paint. Make sure it water based and preferably 100% acrylic. Deft is one brand that is reasonably priced and available as a satin sheen. There are several on the market, check with your local paint stores for other options.
This will go a long way as a clear coat over your paint, you won't need as much as regular paint.
The only drawback is touching up the paint (if needed); you would need to also touch up the clear coat or have a flat spot. Also, it might be a little difficult to get a perfect looking wall but you already went the difficulty of applying a dark flat paint so you have the skills to do this with few problems.