Outgassing is a problem that can occur when framing glossy or semi-gloss paper. It is a reaction that happens when glycol, a humectant, evaporates slowly and creates an oily fog on the glass - similar to the look of condensation.
Glycol is used in printer inks as the water in them evaporates quickly and Glycol slows the evaporation process, preventing nozzle clogs. This outgassing occurs particularly with glossy and semi-glossy papers because there's an impervious polyethylene layer between the paper base and the ink accepting layer on top and because of this barrier, the paper base is unable to absorb the glycol, which would speed its evaporation.
To prevent outgassing occurring on your prints, they must be allowed to dry completely before framing as the glycols evaporate off the print but have nowhere to go, so they condense out on the nearest cool surface in the enclosed space. You end up with an oily fog on the inside of the glass. The only way to get the glycols off the substrate after printing is heat and air movement - a hair dryer is one of the best options! Other than that, just keeping the print warm and letting it get plenty of air or simply hanging it in a warm studio for a few days should be sufficient.
We have never found outgassing with Ultrachrome prints to be a big problem in practice. It could be a more common issue in colder climates than in Australia as we have an overall warmer temperature, but it does seem to be a topic that comes up quite regularly in online forums.
For those of you wanting to understand the problem in more detail and come up with a solution have a read of the the yahoo EpsonWideFormat group and have a look at the attached PDF from Epson, with tips on framing digital prints.