I'm not sure many people would be interested in this but I'm trying to make some poxy instructional videos for YouTube (they take so long to make) and I wanted a black backdrop. At first I thought any old black fabric would do but I noticed black fabrics often aren't all that black.
Ideally, you'd maintain a lot of distance between the backdrop and the subject in which case you can even make a white backdrop look black but that's not possible in the confines of my living room. The best black fabric is supposedly black velvet sold specifically for use in photography/theatres but that stuff is hideously expensive.
I took a chance on this stuff for £12 per 3mx1.5m piece. I'm not sure exactly how long it took to arrive. It's normal to take between two and four weeks but I wasn't desperate for it so I didn't notice.
The main drawback is that its only available in pieces 1.5m wide. It's easy enough to put two pieces side-by-side with the edges folded back to hide the back and selvedge which is shiny. It will also let light through from behind so you can't use it in front of a window without additional fabric (curtains?) to block the light.
I've prepared some photos of side-by-side. They were taken with my Samsung Galaxy S5 in some automatic mode. Having a white pieces of paper in frame adjusted the exposure as you're probably already familiar with. Apart from my phone I have a Panasonic HDC-SD60 which has automatic and manual settings so I could take these again if I did it badly this time. I have no conflict of interest here: I get nothing out of sales of this fabric; I just thought others would appreciate cheap black backdrops and I spent a lot of time perusing forums and listings to come to this choice.