Linen White Paint

I decided to put money and I paint. 1500sq walls and ceiling were painted white porcelain Ft. I will use flat white paint linen ... I'm the first? Or do I spackle, sand, clean the walls and start painting right like that? I'll do the ceiling and the wall of white cloth at once, and semi-gloss on the trim / molding. Is this correct? or do I need to filter the paint, mix it all in one package, etc. .. and only 9 yards? I guess when someone has 5-10 gallons of paint, they mix everything, put it in a large bucket, and filter it, then start like that. Otherwise, different paint cans, so they can have the same name, have ID, and could be darker or brighter. The ceiling in one region has a lot of dirt on him the old paint. It must have been a lot of debris, because if you run your hand over it, you can see and feel all the little balls of debris hanging from the ceiling. I guess I can just sand and repaint on the right? Thank you for your help in advance

It depends on how you want your perfect final product. Mix all the paint is a very good idea and not so difficult. However, if your white is not very different, it seems like an aweful lot of money to spend everything primering just to make one hundredth of the difference in shade does not bleed through the new paint. Personally, I would not waste time and money.

If you want perfection and do not mind spending the $ $ $ 's, then go ahead and boot it. If the questions that many of you, you should go ahead and boot it.

Whether you finish or not initiating, the most important thing is to close all the grease spots and dark spots with Kilzer or similar product, because of dark spots eventually white paint.