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EPO Patent Drawing Rules

Every patent office has its own patent drawing rules that you must follow during the patent application process. Here, we are going to discuss the EPO patent drawing rules that are set by the European patent office.

EPO patent drawing rules are the requirements that are set by the EPO (European patent Office) for drawings, photographs, diagrams, and flowsheets that you must submit during the patent application process. An Inventor must follow the set rules properly for an invention to qualify for a patent without any question. Moreover, an impressive patent drawing helps in capturing a filing date and for an impressive patent drawing, you need a qualified patent illustrator.

EPO Patent Drawing rules: Key Points

You must follow a particular set of rules or guidelines provided by the patent office in order to prepare a good patent drawing. Also, it helps you to save time, money and extra efforts. Some of the EPO patent drawing rules that you must consider are as follows:

Black and White drawings:

According to the EPO patent drawing rules, the EPO generally demands black and white drawings. You must use India ink, or equivalent to secure black lines for drawings.

Black and White Photographs:

The EPO accepts the photographs if they are the only possible medium for illustrating the invention. For example, cell structure, chemical structures, beauty products, etc.

Also, they must have adequate quality so that one can print every detail of the photograph in black and white format.

Coloured Photographs:

A Color photograph is accepted only if you satisfy the conditions for the acceptance of black and white photographs and colour drawings.

Colour Drawings:

You must use colour drawings on rare occasions. They must have ample quality so that one can print every detail of the colour drawing in black and white format. However, colour drawings are prohibited in international applications. They are allowed only if they are the only medium to explain the invention clearly.

The EPO patent drawing rules allow colour drawings only after the grant of a petition that explains the significance of the colour drawings. The inventor must file the petition.

The petition includes:

  1. Petition Filing fee.
  2. A black and white photocopy of the colour drawing with similar details and 3 sets of colour drawings.
  3. You must amend the specification in order to insert the following paragraph at first in the drawing description: “The patent or application file contains at least one drawing executed in colour. Copies of this patent or patent application publication with colour drawing(s) will be provided by the Office upon request and payment of the necessary fee”.

Drawing Identifications:

A Drawing Identification must include:

  • Title of the invention.
  • Name of the Inventor.
  • Application number/Docket number.

You must place this information on the front page and align it to the centre with the top margin.

Size of the Sheet:

Every drawing sheet must own a similar size. You must stick to the following dimensions:

  1. 21.0 * 29.7 cm
  2. 21.6 * 27.9 cm

Paperweight: 80-120 g/m2

Paper Type:

You must choose a drawing paper that is flexible, durable, white, non-shiny and smooth. Refrain using sheets with folds and creases. Also, you must only use a single side of the sheet. Try to avoid erasure marks, overwriting and alterations.


Every sheet must follow the following margin scale:

  1. The top margin of 2.5 cm.
  2. Left side margin of 2.5 cm.
  3. Right side margin of 1.5 cm.
  4. The bottom margin of 1.0 cm.

Also Read: Top Reasons to buy Accurate and Professional Patent Illustration Services

Types of View:

A drawing must contain every possible view of the invention i.e. top view, Bottom view, Side view, Front view, Back view, etc. Also, you must arrange all the views together on the sheet. Also, avoid wasting sheets, keep the position, and maintain a proper gap between the views.

NOTE: Do not use similar sheets for views and claims.

Some other general types of views are:

Partial Views: 

You may break the view of a large device or machine into partial views. You must include a view of the comparatively small scale that shows the positioning of all the partial views.

Exploded Views:

It shows the working, order or relationship of an assembly of different parts. You must place an exploded view within the brackets.

Sectional Views:

A sectional view is used to show a hidden area or part of an object by cutting/removing some of the parts of that object. The cutting line is termed as cutting plane.

Also Read: Design Patent Drawing Requirement – Important Points to follow


You must create a drawing with a scale that shows the mechanism of the invention without crowding. Also, you cannot use indications like actual size or scale 1/2 on the drawings.

Shading requirements:

Shading indicates the surface conditions or shape of any object. Spaced lines are preferred for shading. They must be thin, few in number and must contrast with the rest of the drawing.

Moreover, you must assume the Light coming from the upper left corner at an angle of 45° for shading. Pitch black shading is prohibited. However, you may represent bar graphs with them.


  • Use the English alphabets for letters. However, you may depict wavelengths, angles, and formulas with other kinds of alphabets.
  • You must keep the reference characters such as sheet or view numbers legible and avoid using brackets or inverted commas.
  • You must keep the size of Numbers and letters to 0.32 cm in height. Place them at a clean surface and avoid placing them over figures and shades.
  • Orient them in the direction of the view.


You may use Graphical drawing symbols for conventional elements. You must use symbols to illustrate devices that own a conventional meaning around the world and acceptance in the art. The capital letter of the symbol must have a height of 0.21 cm.


You may use the arrow at the end of the line to indicate the following:

  1. At the tip of the lead line to indicate the entire section in the direction of the arrow.
  2. Indicating the direction of movement.

Lead Lines:

Lead lines connect the reference characters and referred details. You must keep them as short as possible. Lead lines may be straight or curved. Moreover, they must not overlap with each other.

Copyright/Mask Work Notice:

Place a copyright/mask work just below the relevant figure and keep the size of the letters from 32 to 64 cm. Also, limit the contents of the notice as per the law.

Moreover, you must stick to the authorized language to gain a permit for the copyright/mask work notice.

EPO Patent Drawing Rules: Tips

You must take care of some major tips in order to file the application correctly and according to the EPO patent drawing rules. They are:

  1. Submit durable and permanent correction to the Office.
  2. Avoid holes in the drawing sheets.
  3. Number different views and sheets of the drawing with Arabic numerals.
  4. Place authorized security markings on the top of the page, centred at the top margin.

Drawings within Proper Patent Drawing Rules – PatSketch

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