Ripsmatta and rep weave designer

Rep weave, rips in Swedish, is a warp-faced plain weave: the warp is set so close that it hides the weft. The warp ends alternate between two colours and the weft between a thick pick and a thin one, so the colour lying over the thick pick shows, in bold blocks that change places as the treadling changes. Ripsmatta is the Swedish name for a rug woven this way. Chromattice lets you design it block by block and works out the draft.

A ripsmatta (rep weave) design shown as woven cloth — An example made in Chromattice

What the designer does for ripsmatta

Design in blocks, not threads: shaft pairs across, blocks of ribs down, each pair with its own two warp colours, width and shafts. Tap a field to change which colour shows.
Shafts and treadles worked out for you: pairs that weave alike share shafts, and the tie-up gives each face a pair of treadles, balanced for a counterbalance loom.
Checked against your loom: enter your shafts and treadles and the Problems panel flags anything past them.
True size: set the ends and ribs per inch and your reed, and see the finished size and the sley.
The full draft, threading, tie-up, treadling and drawdown, drawn the American or the Scandinavian way, and saved as a WIF for other weaving software.
A print to weave from: the profile, the warp pair by pair, the warp and yarn for each colour, and the treadling block by block.

Good to know

In Swedish the technique is rips; a ripsmatta is a rug or mat woven in it. Swedish rep rugs are usually woven in just two or three colours. (lucienne-repweave.com)
A rep rug is reversible: the back shows the design in the opposite colours. The warp hides the weft, except along the rug’s edges. (rugsofsweden.com)
In Handwoven’s projects, the warp most used for rep rugs is 3/2 pearl cotton at 30 ends an inch; whatever the yarn, set it close enough that the warp covers the weft. (handwovenmagazine.com)
Two thin picks in a row swap which warp colour lies over the thick weft, so the colours change places along the rug. (blog.fibraquarelle.com)
A threading block can be any number of ends, so long as they come in pairs. (evasweaving.wordpress.com)

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