Sizing walls

[Jeebsy]

I'm in the process of redecorating my hall - have stripped all the old layers of wallpaper and paint off but not sure if the walls need sized prior to new paper going up - the walls are the old plaster which has been filled in places. It's a 1910 or so tenement.

They have obviously been papered before so it's not a fresh surface, and I watched one video where a guy seemed to do a test by wetting his finger and running it across the wall to see if it left a mark (although he didn't properly explain it) - have done this on mine and it doesn't show.

Reckon I'm ok to crack on and get the paper up? Or best to size them?

 

[blup]

If the walls are dry and damp free then pasting the paper should suffice. If the plaster is not smooth consider skimming or using lining paper, as imperfections do show up

 

[Jeebsy]

I am using lining paper - sorry if wasn't clear but my question was if i would need to use a diluted coat of adhesive to prep the walls before actually getting the paper up.