Karami weaving is used across a wide range of applications, from industrial mesh to fine cloth for clothing. The mechanism — threads crossing one another — is the same, but making a regular mesh and expressing a complex pattern or handle call for different conditions to be set on the loom.
A way into that difference is the distinction between the double-doup and single-doup methods of the karami heddle. A heddle guides the movement of the warp; in Karami weaving, a purpose-built heddle is used to cross neighbouring warp threads.
By name alone the double method sounds harder, but in its basic form it is the arrangement that more easily keeps differences in warp tension in check. Two sets of doup heddles are mounted facing in opposite directions, and the weaving proceeds while the twist is taken out of the thread. Where a regular weave has to be produced continuously, as in industrial mesh, that stability is useful.
Textile & Fashion, Vol. 25 No. 9 (2008)
When more complex crossings and patterns are wanted, the freedom of the single-doup method comes into its own. A single doup heddle can cross several threads, but differences arise in take-up and tension from thread to thread. The feed has to be split, slack taken out, unintended crossings prevented. Widening the range of expression means taking on the complexity of the mechanism and its adjustment. Sha and Ro, incidentally, can be woven by either method.
"Development of a Special Leno Device" (2000)
Add twisted yarn to that — particularly a hard twist — and there is more again to account for. Beyond the crossing of the warp, the twisting force and the stretch of the yarn itself affect the finished cloth. Research at the Aichi Center for Industry and Science Technology has shown that the twisting force changes with the number of turns and with tension, and that this governs how the weft bends and the three-dimensional form the cloth takes.
Hiroshi Ohno, "Development of a Leno Weaving Technique with Three-Dimensional Space for Incorporating Functional Materials" (2010)
Where to cross, where to leave open, how to use the twist of the yarn. The more character a garment calls for, the more the weave structure and the nature of the thread have to be handled together — and then reproduced steadily on a power loom. The richness of a cloth worn on the body comes out of the work of setting these fine conditions, one at a time.