I watched this somewhere in 2010ish, I think, as a DVD checked out from the library (unfortunately, I check out enough books and movies as to make it difficult to search through their somewhat clunky interface for my history) and probably made around then, with the special effects neither looking dated nor cutting edge (in fact, what I remember is fairly understated, largely practical visual effects and camera angles). A family (husband, wife, at least one child) move into a new house which has many beautiful windows that create designs on the interior floors when the sun shines through them. I want to say that most of those windows were covered with brown paper when they first tour the home, with the realtor making some excuse of trying to protect the flooring from getting damaged by the sunlight.
After they move in, they learn that the person who built the house was a renowned architect who just disappeared one day. Or perhaps the rest of his family disappeared and then he left. I think there's a few scenes where we can see doors visible in mirrors that aren't there when viewed normally. I think the protagonists notice the effect, but assume it's some sort of a trick of the light, or perhaps an intentional optical illusion by the architect. There's an older female neighbor, who they see drop out of sight at her window at some point. I think that the camera moves to inside that house, where the old lady is swallowed up into a pool of dark blood in the carpet, but when the protagonists arrive, there's no sign of her or that blood.
Eventually, they find some evidence (a diary? Notes?) that the architect had found a way to access another world through some combination of lenses and mirrors, and may have built the house to make such a connection feasible. I think their child disappears, leading to them using the notes to find a way to visit the other world, perhaps by blindly reaching for the door that isn't there while watching themselves approach it in the mirror.
Ultimately, I don't remember how the film ends, whether they eventually escaped again.
