It's the ink & 'substrate' (paper, canvas, whatever) match that is of primary concern for lightfastness.
Ink and printer match is probably important too for whatever technical requirements the particular ink delivery system uses (viscosity, fluid dynamics, etc). Skimping on either isn't a good idea. The longevity claims also depend on proper environment. Even UV-filtering glass or acrylic don't guarantee fading will never happen - they slow it down tremendously, but there is enough blue and violet in visible light that it contributes to fading to a lesser degree than UV. UV- filtering acrylic cuts off at 400 nm, vs UV filtering glass at 380 nm (acrylic filters further into the visible range, barely, hence the 98% UV filtering claims vs 97+ for typical UVF framing glass. Murray
