In short, I'd have to mostly agree with ElvisIncognito, that HPLV is the way to go for evenness of coating.
I've already found that rolling paint can cause evennes problems, though I'll state that evenness depends on several application variables:
- The amount of paint put onto the roller.
- The distribution of the paint on the roller.
- The general consistency of the paint being applied.
- The porosity of the material being painted (vinyl/plastics are less porous than cotton/polyester cloth/canvas).
- The way the paint is being rolled onto the screen.
- The reflectivity (gloss) of the paint.
- One's own level of klutziness (read: to not step on the screen, or into the paint pan THEN step onto the screen).
- The ambient dust level of the application room.
There may be more than what I've listed here, but I think my point is made. There are many methods to minimize these variables and come up with a generally good and even application of paint, but I'll stick to a few here to keep things short:
1) Use a paint that is even in its consistency and will not dry too quickly. I would recommend oil-based paints for this, even though they're a lot messier than other types of paints. If you can execute a good coat in short time, then work with the water-based latexes and enamels, though I don't think that you can get good reflective paints in other than oil-based mediums.
2) Make sure the roller used is EVEN all around. The use of a foam rollerhead will help this a lot, as foam holds its shape a lot better than the fuzzy-head rollers.
3) Putting the paint onto the roller should be in slow motions from within the paint pan. Move once from in the 'pool' of paint at the bottom of the pan, giving the roller a good soaking all around, pulling the roller slowly out of the pool and up onto the ribbed area (I forgot the term for this part of the pan). Be careful not to 'push' too much paint onto the rolling area or you'll slop paint out of the pan. Moving towards the paint pool slowly, pressing lightly on the roller to remove any excess paint and leaving an even saturation of paint on the roller. The roller SHOULD NOT DRIP when you pick it up from the pan! If it's dripping, run it a few more times on the ribbed area to squeeze off excess paint until it no longer drips.
4) As others have mentioned in avsforum, painting a screen with a roller involves moving from edge to edge in one fluid motion, preferably along the horizontal of the screen. An initial coat can be applied along the vertical, but make sure the final coats are along the horizontal dimension.
5) In general, flat and matte coat paints need fewer coats, where enamels and glosses need more. Especially for FT projection systems, avoid the super gloss surface and 'mirror' effects. This is where hotspotting the projected image comes from. Use glosses and enamels either as a base for flats/matte overcoats, or use a more textured substrate cloth/paneling material to break up the gloss surface. The use of a fine sand paper after gloss application can help break up the smooth surface and reduce hotspotting as well, though be REAL careful not to sand through the all-critical projection coating.
6) Use a non-porous substrate material to ensure an even coat and use less paint. Cloth is a good choice for 'transparent' screen systems (to put speakers behind), but a more difficult choice to apply a good even coating of paint, as these cloth screens have a habit of absorbing the paint without really allowing the same reflective advantages as if the same paint was painted on a vinyl or plastic substrate. To compensate, use a thicker paint, or apply more coats. Just know that with the pores between the cloth weave can unevenly 'fill' and cause blotching, and no number of coats of paint will totally remove this blotching effect. If you require an absolutely FLAT surface for viewing your movies, cloth should be used either as UNPAINTED (use the natural tone of the cloth) or painted WITH MUCH CARE, preferably before it is stretched onto a frame.
7) Dust. The bane of painters. It is impossible to remove all dust from a good coating of paint, but you can minimize its damaging effects to an otherwise even, unblemished screen:
- Clean and dust the painting room prior to painting the screen, including dusting the tables, doors, windows, and vacuuming the floor with a HEPA-equipped filter vacuum cleaner. Then wait a couple hours to let the remainint ambient dust settle.
- Lay a non-lint drop cloth as a painting base. Plastic drop cloths are preferred here, though don't touch any electronics while doing this, since many plastics and static electricity are bedfellows.
- Arrange your paint, rollers, and screen in a way where you only need to stand in place as you apply the coat(s) of paint. Less movement means less dust being kicked up or 'generated' from your movement.
- Wear clothing that's freshly cleaned, and if you have longer hair, pin it up or tuck it under a shirt. Hair getting into a screen coat is a real eyesore once it's discovered on a screen, and nigh unto impossible to remove without blemishing the even surfacecoat. Not to mention that getting paint in the hair is a b!@t$h.
- If you have pets, absolutely keep them OUT of the room during this whole process! I'm sure we all have a couple stories we could tell about our pets getting where they should be at that 'critical moment'. ;2)
Well, I've used about 50% of these suggestions in my screen last weekend (current living conditions simply cannot warrant all of them being followed), and I still need a few more coats of paint on my screen as it is still a little too reflective and is hotspotting a little too much, but I should be able to give all the juicy details when I get it done. Stay tuned.
That's my 3 yen.