Patch Codes

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Patch Codes

Patch Codes were developed by Kodak to help process large batches of documents quickly and accurately. Unlike most 1D barcodes, which are read from left-to-right, Patch Codes are read from top-to-bottom. They include four bars — two wide and two narrow — and three spaces of fixed width. As a result, all Patch Codes are the same size. 

When read by scanners during document processing, Patch Codes tell scanning or capture software how to classify and organize documents, significantly increasing both the speed and accuracy of document processing.


Patch Codes do not contain any encoded data. Instead, the pattern of the code tells scanning software which specific action to perform. There are six Patch Code patterns:

  • Patch 1 — Wide, wide, narrow, narrow. This is used for post-scan image control.
  • Patch 2 — Wide, narrow, narrow, wide. This code assigns “image level 2” to the scanned document.
  • Patch 3 — Wide, narrow, wide, narrow. This code assigns “image level 3” to the scanned document.
  • Patch 4 — Narrow, wide, wide, narrow. Patch 4 is used for post-scan image control.
  • Patch 6 — Narrow, narrow, wide, wide. This Patch Code is also used for image control.
  • Patch T — Narrow, wide, narrow, wide. Also known as the “transfer patch,” this code assigns a predefined image level to the next scanned document.

Although Patch Codes may be placed on all four corners of a document, only one is read. The extra codes ensure that even if documents are scanned upside down or rotated, at least one Patch Code is still readable. While code functions can be customized, Patch Code patterns 1, 4, and 6 are generally used for color or multi-feed document detection, while pattern 2 is used for document separation, pattern 3 is for batch separation, and pattern T can be used for either.

Common Use Cases

Patch Codes are used to increase the speed and accuracy of batch document processing. With the right barcode scanning software, it’s possible to scan large document volumes without the need to manually separate batches or worry that documents are perfectly aligned. Originally designed and used by Kodak, Patch Codes are now used by large enterprises and on some government tax return forms.

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