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What a Patent Drawing Must Look Like

Written from 37 C.F.R. 1.84. This is a regulation. Current as of 22 August 2026.

What it says

Black and white is normally required, in India ink or an equivalent securing solid black lines. Photographs are accepted only where they are the only practicable medium. Colour in a utility application is necessary only on rare occasions and requires a granted petition, a fee, and a specified amendment to the specification.

Patent drawings look the way they do because a regulation says so, and the rules are more specific than most people expect.

Black and white is the norm, in India ink or an equivalent that secures solid black lines.

Photographs are not ordinarily permitted. They are accepted only where a photograph is the only practicable medium for illustrating the claimed invention.

Colour is the sharpest rule. It is permitted in design applications. In a utility application it is necessary only on rare occasions, and the Office accepts it only after granting a petition explaining why, accompanied by a fee and a specified amendment to the specification.

For anyone whose diagrams are colour-coded by default, that last one is worth knowing before the filing rather than after. A coloured architecture diagram is not a small formatting choice.

What This Does Not Decide

This page is not a walkthrough for preparing drawings or filing a colour petition. The material is procedural, which is what makes the line easy to cross. What the regulation requires is described above. Preparing conforming drawings, and deciding whether a colour petition is worth making, is work for a practitioner or a draftsperson.
  • It does not tell you how to prepare drawings or file a petition.
  • It does not say whether colour would be granted in any case.
  • It does not say whether your application needs a drawing at all, which is the statute and a separate page.

Educational, not legal advice. Whether any of this reaches a particular application is a determination for a registered patent practitioner.

Sources