Roman blinds are a pain in the ass, we have them at work and they never direct the light the way it needs to go. Bit of a bummer as I have direct sunlight from midday to sunset and no prospect of shade (16 floors up) and it crisps my plants if I leave the curtains open over a sunny weekend.

They are also an instant hit with any cat who will wind it's way in and out of them, bat the strings, try to climb them and generally wreck them.

There is available a rubberised lining material called 'blackout' - based on the blackout material available in WWII, it's been impregnated with a rubberised solution, that renders the cloth completely light proof, by sealing all the holes around the weave. I have some in Bratlings' bedroom, because we have a streetlamp directly outside the house. It works well at excluding light and because it's white it reflects the sunlight. The bit between the window and the curtain gets toasty warm, but the rest of the room stays cooler. As long as you don't boil it, tumble dry it or dry clean it (solvents melt the rubber), it is quite washable.

LTS