plexiglass and perceived sharpness

[mminegis]

hello,

I am making 13" x 19" prints for an exhibition, and I was wondering if anyone would consider slightly more agressive sharpening because of the presence of plexiglass between prints (on mat paper) and viewers.
I know that the perception of sharpness also depends on paper size/viewing distance/ambient lighting etc. but I just wanted to know generally if I should consider it or not (and I am not changing other factors ie size and paper - photo rag).
I admit... I have never seen my prints behind a plexiglas (nor have I seen them on a gallery wall   this is my first time).... so I may be off re sharpness etc., but I have a feeling that plexiglass is a bit softer looking than a normal glass... am I wrong?

Mari

[framah]

Yes, you are wrong...    

No need to make a change as it is as clear as glass as long as it doesn't get scratched which  is the Achilles heal of plexi. It is very prone to being scratched. Plus, if you use a cleaner that has ammonia in it such as Windex,  the ammonia will eventually fog and craze the surface of the plastic. I use glass Plus which has no ammonia and have had no problems. Your size images, you can use 1/8" and not see any difference.  Larger than 30 by 30 or so, I would go to the 1/4" thick.

There are also different types out there. There is one called Optium which is very low reflectance and UV protection.  VERY expensive!!! but sometimes worth it.

[mminegis]

Thank you for your advice! I don't know where I got an idea of a soft and mellow looking glass ... maybe it was just hazy  

[bill t.]

If anything your print will look a little sharper under plex, glossy surface glazing slightly increases the perceived contrast of the print underneath.

Acrylite-FF is a great plex that is extremely clear, color-free, ripple free, and cheap.  Dollar for dollar is very superior to same-priced glass.  Locally I pay about $68 per 4 x 8 foot sheet, and my supplier will happily make (almost) any number of cuts in it for free.  If sell able pieces of material are left after making the cuts, they usually only charge me for the actual square footage I receive, there's a little give & take there.

The zero-reflection Optium is amazing stuff, but be prepared to pay an absolute minimum $60+ per 13x19" cut.  If your frame will be handled by the typical dunces who run photo-contests, county fairs etc, don't use it because it will surely get scratched by such folks.