You print out digital photos of loved ones, pin them up on the bulletin board, and a year later the colors look yellowish. One solution is to print out another copy.
Another solution is to use a printer, printer ink, and paper that resists fading. Engaget reports on an 11-month trial, where photos were printed with several brands, posted in a sun-facing window, and copies kept in the dark for comparison.
The winner was the HP PhotoSmart 385. You can read the full story at Fade resistance test takes a look at photo printers / paper. Especially read the comments section, where the tests are critiqued; for example, one writer says airborne pollutants do more damage than does direct sunlight. Another notes that long-image-life paper makes prints look worse.
So, maybe my original solution is best: just print out another copy!