I sometimes used RC Ciba paper for portrait commissions. I looked at my old reference album copies about a month ago, just for fun, and they look like they were printed yesterday, in contrast to the Ektacolor prints, which are already showing a bit of yellowing after only a couple decades. But I almost never used RC Ciba for framed work - just the glossy polyester product - with one exception, a test print hung in harsh direct mtn window light ... and even it lasted 25 yrs before any apparent fading. But intense projector halogen lighting in galleries could be far
worse than sunlight.