Bergdala Spinnhus

On profile patterns

A profile pattern can be seen as a wish: we want to make a fabric with a pattern like this. At the moment we don't know how, but the goal is that the pattern looks like this.
Usually, the pattern appears through the use of different structures for the different pattern areas.

Let us look at a simple checkerboard pattern:

In classical Swedish weaving literature the profile drafts were always blue and white, the detail drafts were in red and white. (Note that Swedish drafts usually are written for sinking shed - white warp with red weft)
In newer books most drafts are in black and white.

So: the goal is a checkered fabric.
How many blocks does the pattern cosist of? Look at the profile draft - it has two (profile) shafts - thus, the pattern has two blocks.
The same is true for the weft: the profile draft has tvo (profile) treadles.

Below are several examples of how this profile can be interpreted:

But how did that happen?

It happened because we saw every square in the profile draft as a "shorthand" represtentaion of something else - something that is not pre-determined: a number of ends woven in a specific way.
We can choose freely what, and how many ends and picks, one square represents.
For example, in the tablecloth above, each profile "end" represents 7 actual warp ends threaded to a point on 4 shafts.

In this way it is possible to weave nearly any pattern - provided that the loom has enough shafts and treadles for the chosen structure(s).

But... if it hasn't? If my loom only has 4 shafts and six treadles - do I have to give up on weaving patterned cloth altogether?

No - 'cos there are other tricks available!
There are several structures that were developed for these cases. Some examples (that in Sweden are called "simplified drälls") are daldräll (often called overshot), jämtlandsdräll (often called crackle), summer-and-winter (in Swedish books sometimes called kuvikas).
The common denominator for the simplified drälls are that they have two weft systems - a plain weave (which form the ground cloth) and a pattern weft that floats over or under the ground cloth. They are woven with two shuttles, usually with a thicker pattern weft.

Below is an example that can be woven in daldräll (overshot).

Here is the profile draft for Cat's paw.

If we were to weave this pattern in "true" dräll (turned twill or satin) we would need a minimum of 12 shafts (with a 3-shaft twill), or 20 shafts (with a 5-shaft satin).
If we instead choose daldräll (overshot), we only need 4 shafts and 6 treadles.

To translate the profile draft to a detail draft we have to determine some rules. These are the rules for overshot used here:
One square in the profile represents four ends in the detail draft. (Other numbers are possible - I am following Manual of Swedish handweaving by Cyrus-Zetterström.)
The profile draft has four blocks - or four profile "shafts". The black square(s) on profile shaft 1 we call "block 1", those on profile shaft 2 we call "block 2" and so on. Each block has its own threading system for its four ends - like this:
(Note: I am using the Swedish convention of numbering the shafts and treadles: shaft 1 is the one furthest from the weaver, treadle 1 is the rightmost treadle.)

If each square in the profile threading is translated to 4 squares, following the rules above, we get a detail threading looking like this:

Now, the treadling:
One square in the profile still represents 4 picks (two pattern and two tabby). To avoid making the treadling too long and cumbersome it is common to leave the tabby picks out. This means that every square will be written as two pattern picks.
(But what if the pattern does not "square"? To quote from the same book (my translation): "The number of pattern picks required before changing treadling block has to be determined for each weave.")

Lastly, we have to translate the tie-up: according to the profile tie-up treadle 1 should lower profile shaft 1. According to the rules above profile shaft 1 is threaded on shafts 1 and 2 - thus (pattern) treadle 1 should be tied to lower shafts 1 and 2.
In the same way we see that (pattern) treadle 2 is to lower shafts 2 and 3, treadle 3 lowers shafts 3 and 4, treadle 4 lowers shafts 1 and 4.
The two remaining treadles are required for the plain weave. Below I put them to the righ. Some weavers prefer to put the tabby treadles on the outsides.

To keep the picture size down, I only included one repeat of the pattern, plus the border, in the threading, and only one repeat of the pattern in the treadling. The tabbies are omitted, but should be woven between every pattern pick: tabby 1 - pattern 1 - tabby 2 - pattern 1 - tabby 1 - pattern 2 and so on.

(If you are interested in jämtlandsdräll (crackle), I have an article here.)