EPO to Accept Colour Drawings from 1 October 2025 – What Applicants Need to Know!

1. The Legal Basis

The update comes via the Decision of the President of the EPO dated 7 July 2025, which now mentions:

“When filed by means of electronic communication, drawings may also be executed in colour or in greyscale, in durable, uniformly thick and well-defined lines, strokes or areas. They must also be sufficiently rich in contrast and suitable to be clearly displayed at a resolution of 300 dpi.”

Previously, the EPO required that all drawings be “without colourings”, with any submitted colour images converted to black-and-white for publication –potentially resulting in the loss of important information.

2. What Changes in Practice

As of October 2025:

• Colour and greyscale drawings will be processed and published as such when filed electronically
• Existing technical and formatting rules remain unchanged (page size, margins, proportions, hatching, reference signs, minimum text height, etc.)
• The 300 dpi resolution requirement applies to ensure clarity and reproducibility

This is especially good news for applicants whose applications contain:

• Colour-coded scientific data (e.g., heat maps, chromatograms)
• Biological or chemical imagery (e.g., staining results, microscopy)
• Complex engineering diagrams where colour aids in distinguishing elements

Allowing drawings in colour or greyscale can greatly enhance the way inventions are communicated to examiners, third parties, and the public. Complex diagrams, graphs, and flowcharts become easier to read when colour is used to distinguish different elements, while subtle features such as shading, staining patterns or gradations can be preserved. This improved visual clarity can help avoid misunderstandings, reduce the need for clarification during examination, and ultimately streamline the prosecution process. In addition, published patents containing colour drawings can serve as higher-quality technical references, benefiting both industry and the research community.

While allowing colour drawings opens the door to clearer and more accurate technical disclosures, it also introduces certain strategic and legal considerations. If colour conveys additional information that is not present in the black-and-white equivalent (e.g. a priority patent application with black-and-white figures followed by an EP application with colour figures), it could be argued during prosecution or opposition that the change added subject-matter. The presence of colour may also influence how a feature is interpreted by an examiner, opponent, or court, sometimes narrowing and sometimes clarifying its scope. Differences in the appearance of drawings between jurisdictions — for example, in colour in Europe but in black-and-white elsewhere — could lead to interpretational discrepancies or even novelty disputes. Applicants will therefore need to balance the advantages of enhanced clarity against these potential pitfalls, and ensure that their drawings remain effective both in colour and in monochrome.

3. International Perspective

While this is a welcome development in Europe, colour drawings remain the exception rather than the rule globally:

Patent Office - Colour drawings allowed?

EPO - Yes, from 1 October 2025 (electronic filings only)

PCT - No, colour drawings may be accepted but are converted to black-and-white for publication

USPTO (US) - Conditionally, special approval required (file a petition justifying necessity, pay fee…)

CNIPA (China) - Conditionally, when necessary to describe the relevant technical content of the patent application clearly

JPO (Japan) - No, only black-and-white lines or greyscale drawings are allowed

KIPO (Korea) - Yes

UKIPO (UK) - No, only black-and-white lines or greyscale drawings are allowed

INPI (France) - No, only black-and-white lines or greyscale drawings are allowed

IPObel (Belgium) - No, only black-and-white lines or greyscale drawings are allowed

NPO (The Netherlands) - No, only black-and-white lines or greyscale drawings are allowed 

This means applicants pursuing multi-jurisdictional protection will still need black-and-white versions for filings outside the EPO and KIPO.

This means applicants pursuing multi-jurisdictional protection will still need black-and-white versions for filings outside the EPO and KIPO.

4. Filing Strategy Tips

• Maintain parallel sets: Prepare both colour/greyscale and black-and-white versions where colour conveys meaningful information.
• Check contrast: Ensure figures remain legible when converted to greyscale — this will help in filings with offices that do not yet allow colour.
• Plan ahead for PCT: Even if you file colour drawings in Europe, they will still be converted to black-and-white for international publication.

5. Conclusion

The EPO’s decision to accept colour and greyscale drawings modernises its approach and aligns it more closely with how technical information is actually presented in many fields today. While the move will improve clarity in many cases, applicants must continue to prepare for the more restrictive requirements that still apply in most other jurisdictions.

For questions about how this change could affect your filings — and how best to balance colour and black-and-white requirements for global patent strategies — our team at De Clercq & Partners is here to help. Please do not hesitate to contact us at info@dcp-ip.com.