Digital BW, The Print

Hello,

My prints, UT-FS ink on Photo Rag, get a lot warmer after some weeks
or months, and there is a little change in the density too. This
happens even under very moderate and incidental artificial light. The
fresh print looks stunning, but after a while it gets too red. The
same happens to prints which are framed behind glass, but here the
process goes a lot slower.

This does not make me happy, and I would like to know:

1. Is this a common problem with UT-FS on Photo Rag? Does it happen to
you too?

2. Can I get rid of this problem by switching to Innova Smooth Cotton
High white paper? It looks a lot like Photo Rag, but will it last?

Thank you.

Igor