Just out of curiosity, I typed the words Tarten colours for MacRoth. ( Slaine's last name.)
I found this page.................
http://www.fhaoil-choin.org/druidcolor.htm
I thought it may be of interest.
Not that I'm demanding that this much realism should be
paid attention to as it's mostly make beleive anyway. As this is one of the more mundane aspects of the comic/game. It would be interesting to find out if Slaine has been drawn/painted with the correct colours.
Incidently, I recall TootHill Man, saying that the High Kings personal tarten is a combination of the three primary colours combined. Which sounds fair enough.
It also says in this paragragh that they use seven colours which no-one else but the High King has a right to.
Regarding the suggestion I made before that Slaine could very well bewearing that light cream coloured tarten with dark brown stripes, but stained read from blood in battle. I personally like that idea.
As I have now read on the above page that only royalty have the colour of scarlett/red on thier own tartens.
This might also explain the reason for going into battle, Skyclad. It was noted by myself that Slaine ( Before he was King.) often went into battle Skyclad with the other Red Branchers. Unless they are considered royalty, my hypothesesis won't make much sence.
For Royalty, thsi was more of a option than a rule.
But the reason for them being skyclad was due to the fact that it may have been forbidden for them to have blood spilt on their own tarten clothing after wading neck deep in blood as Slaine might boast. As blood stains are notoriously hard and next to impossible to get out of clothing after it dries.
The High King might take offence at seeing the common rabble wearing red stained tartens only reserved for royalty.
So, off with the clothes while preparing for battle.
Red is the forbidden colour.
So skyclad it was. Although they may have gone this way becuase it was another way of offending the overdressed Romans and that their clothing may be ruined by fighting and being warped. ( Not having a Hero Harness.)
A good seamtstress/tailor that doesn't charge a high fee for their services, perhaps was harder to find in the Land of the young.
My appologies if somebody for official reasons knows otherwise and just remember this isn't official, I only made this up.