instead of just a wall,if you have white walls?
Whats the best overall screen material? Overall best brand (quality/price) ?

Carada

Walls are not perfectly flat.

instead of just a wall,if you have white walls?
?

Imagine going to a theater without a screen. What if they just used a white wall?

You can get a screens that have different amounts of gain (brightness). You can also get ones that reject some ambient light. Also grey screens can increase the black level which is a benefit for most LCD projectors. The type of screen you need to get will be dependent on your projector and viewing conditions. Depending on the screen, there could be a big difference in your picture or it may be very similar to just projecting on the wall. However typically any benefit will have some drawback. (High gain screen may have a narrow viewing cone or grey screens won't have as much gain, etc.)

If you went to the effort to make the wall as good as a screen (Screens have a lot of technology and research put into them) then I really don't see there is much if any difference.

You have some great screens out there for cheap, there just isn't to much incentive to not use a screen these days. A manual pull down installs in 15min. :)

This is the kind of question you should answer for yourself not ask a bunch of strangers who are HT hobbyists.

It is right to be sceptical about screens. People pay good money for bottled water rather than drink tap water even when it can be demonstrated that the bottled water is worse than tap water or actually is just tap water. People like to pay more. The simple fact that people spend money doesn't prove much. Hobbyists will pay for all sorts of things just because hobby purchases aren't supposed to be rational.

You should order some samples of screen material and tape them to your wall. This is fun. Its a hobby after all. Try some different shades of paint on pieces of cardboard. The member called Tryg published his extensive experiments a while back. At least the simplest of these are easy to duplicate. By all means buy a can of Rust-O-Leum aluminum spray paint. If you like the high gain effect you can consider a high gain screen. (I would buy rather than paint if I were you). Or you might like the light gray screen effect. A lot depends on the brightness of your projector and the qualities of your room, but much of it is also just personal preference.

Sometimes advice on this forum is useful (posts like this one for example) but mainly you should value testimony more than opinion. And don't deprive yourself of the fun of your own experimentation.

Thanks everybody.Will have to do more research.
If you knew how far I am in the process of building an HT setup you'd laugh - I dont have anything outside of my head - but I like to do my homework far in advance so to not waste my time and money on mistakes when I actually get to it

A smooth flat (not shiny) white wall is going to be 95% as good as a 1.0 gain screen.

If I didn't have a screen, I'd be projecting onto a window.

Some rooms NEED a screen.