Making a blind black out

[alwaysmovingforwards]

Hi ladies, I've got a roller blind in a room and love the design... but it's thermal and hence let's a fair bit of light in.

To avoid replacing it, would it be possible to add some blackout liner to it?
Any recommendations where to buy said liner and how to apply it?

TIA

I bought the fabric from John Lewis and made from scratch, which I imagine is much the same. You’ll need to get the stiffening out, I suspect, which may mean a lot of hem unpicking.

Actually, scratch that. Roller blind should be fine as you can just skip the poll at the bottom out.

Don’t make the mistake I did on one and not get the fabric right to the edge because there’s a seam so it’ll be fine. It isn’t!

Brilliant, thank you.