Roman blinds in a sheer fabric? Certainly madam!
Yes, it’s possible!
Don’t let anyone tell you it can’t be done. The first photo is a bathroom that the client wished to obscure the sight of ugly screening outside the window without cutting out light. The fabric is a stunning sequined sheer. Blow up the image to see. The second image is the same fabric as a sheer curtain.
More commonly, though, we do lined romans using the sheer fabric employed elsewhere in the room as curtains – typically in bedrooms with those short windows above the bed. Often there will be a plain blockout fabric for the roman which teams with the sheer curtain fabric well enough. But sometimes there is not. As a roman blind, though, the sheer needs to have some texture and interest to disguise the lining behind.