My Father has had vinyl wallpaper on his walls for about 11 years and wanted to change to having two different colours of emulsion onto plain walls.The general concensus of opinion is that you can't paint onto vinyl wallpaper because the emulsion will 'skate' on the surface and not form a permanent bond.Instead the advice is either to undercoat the walls with an oil based paint or acrylic eggshell first or a proprietry primer ( more expensive) or strip the walls completely,prepare the sub strata and paint on that or strip off the top layer of the paper and paint the backing paper ( which may bubble) or strip the whole lot off and re-line then paint.Despite this advice I decided to test an area of the wall by painting a 9inch square with Johnson's covermat white matt vinyl emulsion and let it dry.After a day I tried to see if I could scratch /aggitate the paint but it would not budge.I then put a further coat of white onto the first coat and allowed to dry to see if the second coat would bond ok.This it did and I was unable to scratch it off so I continued putting two coats of white onto the remaining walls to block out the pattern and start with a 'blank canvass' After putting two further coats of the desired colour onto the white it looks great!It takes two days to put two coats of white on first as opposed to a half day stripping,then possibly 1-2 days to re-line.Provided that the original wallpaper is hung neatly in the first place you might find this a quicker & simpler way of freshening up the room.In no way am I trying to undermine any proffessional decorator who dissagrees with this method but sometimes trial and error works