Tartan URL's

Introduction

In exploring the tartan of the Drummonds of Megginch I have wanted to find a unique way of naming the tartans. There are a number of existing registries of tartan but they tend to classify the tartan by number and keep the description closed. The current registers have as an ancester the Register of All Publicly Known Tartans which was maintained by the Scottish Tartans Society from about 1963 to 2000. There were two descendent organisations theScottish Tartans Authority formed by members unhappy about the leadership and the Scottish Tartans World Register.

In 2008 the Sottish Parliament established a register, The Scottish Register of Tartans (SRT). If there any queries they typically go back to the Scottish Tartans Authority for reference.

The Scottish Tartan Register have a formal list of colours that are used for tartans and also describe the colour in a number of the shades which are given RGB colours.

There other formal list of colours and tartans. A book of Scottish tartans Vestiarium Scoticum (VS) was produced between ca 1820 and 1842 with a fake history. Google has ascanned copy without the plates. On Wikipedia it has a nice list of all the colours used. The colour letters don't match with those on the Scottish Registry for two reasons.

Black is descrbed as 'K' by SRT and 'Bk' by VS
in SRT 'LB', light blue is a match for 'Az' Azure in VS.

The user Celtus has provided colour diagrams of all the colours in 2007 but the Wikipedia user account is no longer as Celtus has retired. He/She was working on WikiProject Clans of Scotland

Patterns are typically symmetric with some asymetric. A symetric pattern reverses and the repeats. It has the same colours on both warp and weft directions. An asymetric pattern is nearly has nearly the same patter but not quite.

Tartan Descriptions

Existing Tartans Descriptions

Here are some examples of tartan descriptions:

The Scottish Register of Tartans requires you give two bits of information:

A threadcount eg:

DR/8 G64 K44 G/64

and a colour description (there is no default colour description although they do provide a standard guide:

K=BLACK;DR=#8B0000#DARK RED;G=GREEN;

Note that the parser just uses the presence or absence of '/' to denote a symetric or asymetric tartan.

The Wikipedia entry for Vestiarium Scoticum shows only symetric tartans with like this eg for Clan Gregour(sic):

https://en.wikipedia.org/wiki/Vestiarium_Scoticum

R128 G36 R10 G16 W4

The bold at either end is not actually used but just indicates pivot points.

Tartan Description File format

The defintion of this is embedded in

ABNF Tartan Description

So a Tartan description could be described using Augmented Backus Naur form:

TartanDescription = WeftPattern / WeftPattern ColourDescription / WarpPattern WeftPattern ColourDescription

WarpPattern = ThreadPattern

WeftPattern = ThreadPattern

ThreadPattern = (SymmetricPattern / AsymmetricPattern) [ColourDescription]

AsymetricPattern = 1*Thread / SymmetricPattern [ReversedReversableColours]

SymmetricPattern = PivotColour [ReversableColours] PivotColour ;First pivot should be first in sort of full name

ReversableColours = 1*Thread

ReversedReversableColours = 1*Thread ; ReversableColours in reverse order

PivotColour = Thread

Thread = Colour Count

Colour = 'LR' / 'R' / 'DR' / 'O' / 'DO' / 'LY' / 'Y' / 'DY' / 'LG' / 'G' / 'DG' / 'LB' / 'B' / 'DB' / 'LP' / 'P' / 'DP'

Colour /= 'W' / 'LN' / 'N' / 'DN' / 'K' / 'LT' / 'T' / 'DT'

Colour /= OldColour ; OldColour is deprecated

OldColour = 'Az' ; Azure read as 'LB'

OldColour /= 'Cr' ; Crimson read as 'DR'

Count = 1*DIG

ColourDescription = Colour

If no colour description is provided then a default colour description is used.

The STR adds a / to denote a reversal of a pattern;

I am looking to provide a way to normalise TartanDescriptions.

The STR has a comparison tool, you give it a colour pallet and thread count and a search will be done. It returns a poor quality JPEG. The find similar tartans seems very slow if it works at all.#

VS has an unusual Tartan where Farqueson of Invercauld uses a Y/W6 in order to indicate a repeating pattern eg defining only a quater pattern with a variant. However the pattern is more complicated and essentially tries to use lowercase to indicate one part of the pattern only in one part of the quarter repeat but gets it wrong / indicative only.

STR uses the / to inidicate that the tartan should be treated as a half pattern. If the number is omitted then the colour just repeats, however only the last one can repeat as spaces are removed. So G W4 is treated as GW4.

Approach

Symmetrical and Asymmetrical

Assume that the Tartan is symetrical (as most are), ignore white space and for URL mandated to have no white space:

Simplest describing a symetric tartan:

www.tartan/R2G2B2

and normalised to:

www.tartan/B2G2R2

An asymetric tartan

www.tartan/-B2R2G2

Repeating threads

www.tartan/R2G2B2

Eg the simplest McGregor tartan is described as:

www.tartan/K2R2

then the Tartan Register version could be described as:

www.tartan/K100R100

which could be normalised to:

www.tartan/K2R2~50

Varying Warp and Weft

A tartan with different warp and weft could be described:

www.tartan/R2G2B2.K2Y2B2

WithColourDescription

Only partial colour descriptions are required as otherwise defaults are used.

www.tartan/K2R?R=A00000

www.tartan/K2R?R=A00