This doesn't, however, stop me from mulling over a ton of other things in my head, especially during my very long commutes each days. One of those is about color in the Viking Age. Archaeology tells us that they had a range of dye stuff to use. We see walnut browns at Hedeby, reds that stand the test of time at Oseberg and blues pretty much everywhere (and far more than this brief list).
One thing I often see when reenactors are looking at textiles for sale (for a new garment, that is often to represent someone with at least some amount of wealth) and ask online if that cloth is an appropriate color, is that people will respond to anything in a red, yellow, blue range (and others) with a resounding YES, even when that color might be exceptionally dilute (to the point of being pastel). Is that color feasible with period dyes, of course! However, would it really have been worth it to a person in period to use something as precious as madder to get only a very pale pink, or would it have made far more sense to wait until you gathered enough (or could afford enough) plant matter to produce a well-dyed garment.
I understand that yes, dyes will fade, but realistically, by the time that that happens, that garment would likely either 1) have been re-dyed or 2) be moved from serving as a "better" dress, to, perhaps, work wear? I also realize that you would not be likely to wast the partly exhausted dye bath, and would opt to dye other things, but again, would you really be dying your new body garments this way? Would it not be better instead to over dye an older item, or dye some leftover yarn for some other purpose, or perhaps over dye a naturally pigmented brown or grey wool to change the shade?
Due to textiles degrading in the ground, I dont know that we could really prove this, but we do see a number of textiles from period that still have a very clear, well-saturated color to them, and those things make me wonder if someone long ago would have liked a soft blue garment as much someone today might.