What factors affect print fading?

[shaocaholica]

So prints fade with UV exposure right?  But what other factors affect fading?  Humidity?  Temperature?  Paper type?  Ink type?  Of course some variables are easier to control than others.  Just want to hit the low hanging ones first.

[Lessbones]

All of the above.  But yeah, UV would be the first concern for most types of color prints (C-prints, dye/pigment inkjet) if you're printing on an archival paper stock.  If the paper isn't acid-free then you're in trouble regardless.  It's also been shown relatively recently that the blue light component of LED lamps can be almost as harmful as UV when compared to UV-filtered incandescent bulbs of comparable CCT.  But basically low hanging fruit would be ink and paper (something you can at least control as the printer), followed closely by quality of illumination (something that you MIGHT have influence on depending on your clientele).

[mearussi]

Indoor air pollution like ozone from a refrigerator and smoking.

[Ryan Mack]

I'm not aware of humidity causing fading, but it can cause paper warping, shrinking, etc. If your work will be on display in a space with large changes in humidity (Boston, for example) you need to be very careful of how you mount it to allow for size changes (hang mounting) or to prevent them (dry mounting onto mat/foam board).

[fdi]

All the things mentioned are why picture frames with glass or acrylic that include UV filtration are critical for print longevity. The absolute worst thing is direct sunlight. It is so bad that a print with UV-filter glazing can still fade more quickly if it is in direct sunlight than a print that has regular glazing (which can still block 50% of the UV) that does not receive any direct sun light. Although UV-filters are great many paper manufacturers started including optical brighteners which actually use UV-light to make them brighter. UV-filter over such prints can make them look faded instantly. I talk about this more on here if you interested: OBA Inkjet Paper and Framing Glass Choices

There is also plenty of info about this topic here: Aardenburg Imaging & Archives

[Kyle Jackson]

It's my understanding that "off-gassing" from other print media near prints can also affect colour-fastness.

Some media also discolour/stain in low-light storage.