Slide 1
A pattern begins before the cloth
Jacquard punched cards tell a loom which lengthwise threads to lift. A textile pattern can be recorded as holes before it becomes cloth.
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A sequence of punched cards can determine which warp threads a Jacquard mechanism selects during weaving. The pattern is therefore represented in a separate physical form before it appears in cloth. Holes become instructions through the mechanism that reads them.
Slide 2
Selection changes the opening
Warp threads run lengthwise on a loom; weft threads cross them. A Jacquard mechanism selects warp threads to open a path for the weft.
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The cards control selections of warp threads, creating the opening through which the weft passes. Different selections contribute to different woven patterns. How a particular hole produces a movement depends on the loom's mechanism; the punched card directs that mechanism rather than weaving cloth by itself.
Slide 3
A sequence carries the pattern
A woven design depends on a sequence of thread selections, not just one card.
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One selection is only part of a woven design. Presenting cards in sequence changes the selections as weaving proceeds, and repeating the sequence repeats its instructions. This separates the physical record of a pattern from the continuing movements of the loom.
Slide 4
The tool behind the instructions
A surviving Jacquard-card hole punch in the Science Museum Group collection reveals how the instructions were prepared.
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A surviving hole punch in the Science Museum Group collection records another part of this process: making the cards. Its Coventry context connects encoded instructions to textile work. The object makes preparation visible alongside the better-known spectacle of a working loom.
Slide 5
Repeatable instructions, skilled work
Jacquard cards demonstrate how a textile pattern can be encoded as repeatable mechanical instructions.
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The cards show how a manufactured pattern can be represented as instructions that a mechanism can follow repeatedly. That is a specific achievement in textile production. It does not require calling the loom the first computer or attributing all programmable weaving to one inventor.
Sources
- Hole punch, for making Jacquard cards
Science Museum Group