Apron Dresses--More of the Blues

At the suggestion of Hilde Thunem, I re-read an article about dye testing of Scandinavian archaeological textiles that I'd obtained and read years ago.  The article is:

Penelope Walton: "Dyes and Wools in Iron Age Textiles from Norway and Denmark," 7 Journal of Danish Archaeology pp. 144-158 (1988).

In the article, Walton was interested both in analyzing specimens for dyes used and for wool types, in order to try to draw conclusions about the possible origins of the fabrics involved.  She drew samples from Norway, Denmark, and Germany, ranging in period from the Roman era to the Viking Age.  Consequently, only about a third of the samples analyzed were from the Viking Age, and none of the samples were categorized as to the type of garment from which they might have originated.

Walton extracted dyes from the samples with solvents and examined with at U-V/visible spectrophotometer; paper and thin-layer chromatography were used to confirm positive results for dye. Unfortunately,  the  dye results for most of these do not unambiguously appear in the results table in the article.  However, Walton makes some interesting comments in the text about dye results for a few of the Viking age specimens, even though the main thrust of the article was how the differences in wool type could pinpoint whether particular  textiles had been made in Scandinavia. In particular, Walton's results indicate that the "Birka-type" diamond twills--the type of fabric that was associated with the apron dress layer in the Birka finds--were most often blue, and blue was the most common color in general:

The most common dye to be identified was the blue indigotin (fig 3) which at this time almost certainly derived from the woad plant, Isatis tinctoria L. (the other possible source being the sub-tropical Indigofera tinctoria L.) Although woad is not a native of northern Europe, archaeological finds of its seeds suggest that it had reached Scandinavia by the Roman Period.

Indigotin was identified in fine and coarse textiles of all periods. In several of the Norwegian finds it seems to have been used for particularly dark shades:  at Evebø/Eide it formed a rich, deep stripe on a red or orange ground; in some of the Veka-type textiles only the warp had been dyed, so that the diagonal lines of twill would have stood out as dark blue on white; and in the Birka-type diamond twills, the dye was so dense that it was almost black.  Since woad is an especially difficult dye with which to work and the deeper shades of blue require repeated dyeings, this is yet more evidence that the makers of the Birka-types possessed considerable skills.

Page 153-54 (emphasis supplied).

One Viking age specimen was found to have been dyed with lichen purple, but it's not possible to identify from the article the type of garment from which this specimen may have come, and lichen-purple appears to have been rarely used in Scandinavia according to Walton:

Another rare dye of some significance is the lichen-derived purple found in textiles from Thorsbjerg in northern Germany and Fløjstrup in Denmark. This dye may be obtained from a range of lichens including some which are native to Scandinavia. However, although the dye was available in the north, knowledge of its use seems to have been rather limited.

(Page 156) (emphasis mine).

We don't know what kind of garments or other textile items these Viking era specimens might have been.  However, at Birka itself, the fine diamond twills are believed to have been from the apron dress layer, judging by where they were found in the graves.  If that is also true of the "Birka-type" diamond twills Walton discusses in her article, it is interesting that these twills are also dark blue--in fact they are "so dense that it was almost black."  It is also striking that, of the various Scandinavian textiles that tested positive for dye (as opposed to natural wool pigment, which Walton distinguishes in her test results), most were found to contain indigotin--i.e., blue. 

Though there may have been things I missed because of my difficulties in interpreting the tables in which Walton reported her results, it appears that Walton's survey showed that blue was the most common dye in Scandinavian prehistory--including the Viking period.  That makes it a bit more likely that apron dresses were dyed dark blue--if they were dyed at all.