Yesterday
bippimalin came over to help me dye linen fabric with madder. or rather, with the preparations, we haven't reached the madder stage yet. In the Uvdal 31 grave there was also a linen shift, which had remnants of tannin and madder in, showing it to once have been dyed peach, orange, red or something like that. This (of course) had to be tested so yesterday we boiled coarse linen fabric (12threads/cm, the original had 8 threads/cm!) with soda and then immersed it in a tannin bath, achieved with green tea. Oak gall apples would have been a more period source for tannins, but also much more expensive and hard to get.
The fabric soaked in there over night and was then put in a mordant bath with alum. Now I'm rinsing it in the washing machine and when that's done I will put it in a bath with 1,5 kg madder, which has been lying in water for 24 hours.
This alone shows why dyed linen was extremely uncommon, it was too expensive for a fabric mostly used for underwear. Madder wasn't that costly, but if you need half again the weight of the fabric it still becomes rather expensive. And of course I have no idea how the dye will take or how well it will stand washing, an important thing when it comes to linen clothing, since it doesn't "clean itself" the way wool does.
The dyeing process is also pretty hard on the actual fabric, you need to remove the part of the fibre that makes it strong and shiny.
So, even if there are enough examples of linen being dyed (Egypt, this shift, the lining in the Queen Margareta gown etc), I still think that it was pretty uncommon. Outside Italy and the eastern mediterranean linen seem to have been used only as underwear and headdress and while I think the latter may sometimes have been dyed, it would probably have been easier to opt for a silk veil if you wanted colour, since the linen ones would have been expensive too. Underwear, on the other hand, would have needed to be laundered many times and dyeing which weakens the fabric and (possibly) wasn't hardy would probably not have been very common. It's not like we see a lot of dyed underwear in medieval paintings either.
But now I'm off to grind 1,5 kg (dry weight) wet madder into smaller pieces. Yummy!
PS. Woad may be an exception, there are more finds of woad dyed linen than other colours, and woad is the only natural dye that really "bites" on linen.
PPS. I'm NOT saying that there
never was dyed linen, I'm talking about what was
probably the most common in the Middle Ages. I'm a professional historian, I never say "never".