In article <46o4kc$5ep@epx.cis.umn.edu>, wenner@biosci.cbs.umn.edu says...
>I've heard that using a matt works well. I've been planning to try
>this since I don't have a 20x24 easel.

I just plunked down real cash for a used 16x20 4-blader, but I used to use an easel made out of two hinged layers of matte board with a cutout
for 15.5x19.5 and a flip-down strip for printing 35mm negatives - worked
well, and the price was right.
Hope this helps.