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Perspectives

Print Pad Durometer — Same Thing as Hardness?

Durometer = hardness. Albert Shore named it in the 1920s. Here's the color-code chart pad makers use and how to pick the right pad for the part.

December 3, 2020

Albert F. Shore developed the durometer in the 1920s to measure material hardness. The terms hardness and durometer became interchangeable as a result.

Color-coded durometers

Pad-print pad manufacturers typically color-code standard durometers:

  • Blue: 10–60 hardness
  • White: 20–65 hardness
  • Red: 30–75 hardness

The harder the pad, the higher the Shore durometer rating. Three basic durometers are standard in the industry. A durometer gauge is recommended for determining pad hardness and quality control.

Picking the right hardness

Selecting proper pad hardness involves experimentation and experience. Generally, harder pads perform better and last longer, though they may not suit all applications. Guidelines:

  • Use softer pads for contoured or fragile surfaces
  • Use hard pads for textured surfaces or recessed areas
  • Consider special pads for abrasive substrates
  • Avoid mixing different durometers on the same application to maintain consistent ink-deposit thickness