Needlepoint question

[gracehatter.livejournal.com]

My sister in law showed me some needlepoint work she is doing and she is using floss and I have a question about what kind of canvas she may have been using. (She is on vacay so I can't reach her for a month to ask) The canvas was not a thick plastic but a very thin firm materiel on which the pattern was either printed or dyed. I know it was not burlap, linen, monks cloth or even a cloth, it is to be a picture for framing...it would not be suitable for any other type of project. Any ideas on what this is called?