The size of my black lines!

Anamorphic dvd 480p movies when filmed with a 1.78-1.85 aspect ratio will have thin black bars on the top and bottom of the screen on a native 1.78 aspect ratio projector like your 72. If your rear projection set is a 4.3-1 aspect ratio model ( you did not state this in the post so I am just assuming ) then the black bars will be much thicker.

I am not a bright bulb here and can only post from personal experience. If you projector has a native aspect ratio of 16:9 (N. American HD standard - NOT film) then it will have to scale any content (like most films) to a wider than native aspect ratio which will cause the s0-called black bars and the wider the aspect ratio of the film the larger these null areas of the thrown image will be.

So much is made about the "bars" and we don't get the big deal BUT we chose a gray DA-lite screen and intentionally bought a big more square or 4:3 type. We did this so we would have a lot of flexibility in adjusting all kinds of diffferent aspect ratio content to different size images - we believe that is why most commercial Theaters have very big and square screens - so they can show most any type of content.

Anyway, our gray screen makes the "bars" hardly visible - we don't understand why so many prefer bright white screens - they make the "bars" very visible and annoying PLUS they cause a lot of light room reflection.

IMO - your going with a much thinner and wider screen will not have the effect you think it will plus it will limit your ability to watch older tv programming and older films produced with 3:2 aspect ratio.

Trying to watch some of those fine older films on a very wide and narrow screen will give you a small image with huge vertical black side bars so we recommend you not use a screen made to accommodate only very wide aspect ratio content unless that is the ONLY content you will ever project.

16x9 is the compromise between cinemascope and 4:3. Nearly half of all movies are filmed at cinemascope width and will present black bars on your 16x9 screen. Some people do build themselves a 2.35:1 screen and zoom the image to push the bars off the screen. Others just live with it. A few have purchased an anamorphic lens and through a combination of signal processing and the lens, have a cinemascope image without needing to touch their zoom dial.

I use my HTPC to zoom in and take out the borders....on 1080p material, the scaling is still pretty good and preserves most detail but for 480p sources, it kills the picture. You still lose some view from the sides but at least on my 120" screen, the borderless picture definitely gives u a 'theater' feeling. On my screen, some movies have borders that are almost 1/2 feet thick each side so a 120" screen appears more like a 92"!!

Borders suck but are needed to maintain the true theaterical aspect.