So I posted a month ago about the police suspecting me of growing cannabis due to the tinfoil light-proofing over my bedroom windows. Among the responses to that was one from shermarama, who pointed out that hydroponics shops will actually sell you reflective plastic sheeting designed specifically for keeping light in or out, and that this might work better than tinfoil.

In fact the tinfoil, although the best idea I had yet come up with, is not terribly easy to work with due to tearing very easily. I made a couple of biggish holes in it when I put it up, and then there were an enormous number of pinpoint holes which it seems to have been gradually developing over a year by no terribly obvious mechanism. So at the weekend I placed an order over the Internet, and yesterday I celebrated the summer solstice by taking down my ad-hoc tinfoil and replacing it with proper blackout sheeting designed by professionals.

The same shop also supplied a 50m roll of light-proof metal foil tape to fasten the sheeting with. This impresses me in particular because I'd previously bought metal foil tape from Mackays who charge several pounds for a three-metre roll; I had assumed the high price was an unfortunate consequence of the nature of the stuff, but now I've bought 50m for under a tenner I suddenly believe Mackays' price to be an unconscionable rip-off.

Actually putting the stuff up was surprisingly fiddly. The most difficult bit was cutting the sheeting into the right size pieces, because it's so big (I got a 2m × 5m piece) and staticky and slippery that it's almost impossible to lay it out flat and measure right angles and distances on it. I think I know how I'd do it better the next time (start by measuring all the pieces you're going to need, work out the smallest rectangle of sheeting you can cut all those pieces out of, cut that rectangle off the main sheet and then you might have a fighting chance of opening that out flat for subdivision), but this time was quite a pain.

But once you manage to get the stuff up there, it works extremely well; I recommend it. Definitely better than any of my previous solutions. My windows are still not perfectly light-proofed (the main source of leakage is now crinkles in the metal tape where I put it up incompetently), but I've now reached the point where more light is coming in round the bedroom door than through the windows by a full order of magnitude, and that's more than good enough.

And now I've got reflectively covered windows, high electricity bills (well, in winter at least) and a paper trail linking me to a hydroponics shop. The search warrant can surely only be days away :-)