This week's material has nothing to do with sewing unless you consider that fabric also fades with UV exposure!
UV blocking window film is a great solution if you want to have your resin dolls on display without having to worry about yellowing. The resin BJD community is a bit alarmist when it comes to yellowing. Before I got my first resin, I read up on all the BJD care guides which give you the impression that your dolls will turn lemon-yellow in a month or two if you don't keep them in their boxes.
Not sure how accurate that is, but I've had UV-blocking window film in my office for over 2 years and have BJDs on my desk right next to my window:
Zero yellowing. I'm sure someone out there is going 'BUT HOW CAN YOU BE SURE?!' That's easy:I also have extra hands that do live in boxes, along with non-resin dolls that are a color match to the resin dolls (I even have one hybrid doll with a resin head on a Hujoo ABS body) so if there was any kind of color difference, it would be noticeable.
So what is window film? It's like a giant roll of saran wrap with a slight tint to it. Not nearly as dark as say, sunglasses, but a definite slightly blue-gray tint. It cuts about 10% of the light coming in through the window at most, but blocks 99% of UV rays (the spectrum responsible for yellowing your dolls and aging your own skin) and hugely reduces heat from the summer sun and heat loss in the winter. So it's also great for your heating bills as well as the environment! I liked it so much I did the rest of my house.
There are a few different brands. I can only comment on the type I used personally, which is Gila's Platinum line. You need to clean your windows, spray them with their application fluid, apply the film, squeegee out the extra fluid, trim the film to the exact window size (a box cutter works great) and... that's it.
They have videos on youtube about how to apply it that are all I needed to watch to apply the film just as smoothly as the guy in the video. The only thing I'd add is that sometimes bulges form in the window film that are NOT bubbles, just collections of fluid. This happened with film I bought from Amazon, but not film I bought from The Home Depot (so there may be a quality difference between what each store gets). If that happens, don't freak out and redo the window, just wait a couple of days and it should go away. <--used up a couple of rolls and had to email the company before I found that out >.<