White projector screens are the most commonly available out on the market now and since they are massed produced they are much cheaper than their black counterparts.
There isn’t really anything special about white projector screens, but if you are in a small space projecting and just want to set up a mini projector setup you can easily use a white wall as your screen instead of having to buy a projector screen.
This will save you some money, but also it is nice and convenient as you don’t have the struggle and hassle of setting up a screen every time you take your projector somewhere different, just find a white wall, plug in your projector, find a movie, and start watching! Easy as that no extra steps.
The problem with white screens is they don’t offer as wide of a variety in colors and contrast. Since the screen is white it often washes out the color and makes it difficult to read text on the screen or just in general view what you are projecting.
Also, white screens are not very optimal for rooms with a lot of ambient lighting as the other light in the room along with the white screen makes watching anything on your projector difficult especially if your movie has a lot of white in it you don’t get that same depth as you get with a black projector screen which just makes the whole experience with your projector, not the best.
This is unfortunate as I said white projector screens are much easier to come across and cheaper, but using a white screen in a daylight projector setting won’t work very well.