rabbit hole indeed. you cannot make pixels appear that were never there to begin with.

High-def projectors have an aspect ratio of 16:9. A 2.35:1 image on Blu-ray is 1920 pixels wide but only 800 or so pixels high, with the remaining pixels going to waste to encode black letterbox bars.

with a outboard lens combo the goal is to have the projector electronically stretch (manipulate) the 2.35:1 image in the vertical dimension, so the display chip’s full pixel array is dedicated to showing only the active image area, not black bars as well. The lens then optically stretches the image in the horizontal dimension. When this is done right, you get a 1920 x 1080 image with a 2.35:1 aspect ratio (the projected pixels are rectangular instead of square). It cannot increase the actual resolution; there are only those original 1920 x 800 pixels in the 2.35:1 source to begin with.

But it does use all the pixels on the projector’s imaging chips, which is where you get the potential for added brightness. The downside is A possible loss of resolution due to the added processing and optical elements involved. The latter could also potentially decrease image contrast.

also - what about movies that switch between 16-9 and 1-78 in the middle of the movie?