Suraj,

For ceiling it is not that easy if it is already plastered and painted. You can go for paint, panelling or wallpaper. What location we are talking about.

Thanks
Nitin
Cornerstone Designs Bangalore

living/dining/kitchen it's an open layout like in one of the images.
the ceiling is uneven so we are planning to get it fixed with re-plastering. I might not be able to get a skilled painter in my budget to get the textures right, so I thought by just applying a coat of cement I wouldn't need a very skilled worker and also get the industrial look.

Well Suraj, wish it was as easy as you described. Just a suggestion, please let them try hand on a smaller area first.

Is there any ratio of sand to cement I should use for a smoother finish?
Is there a way to control the colour of the concrete?

Yes Suraj, there are cement color additives that you can add to the mixture.