Patent Drawings in Ireland: 9 Critical IPOI and EPO Rules

Ireland is the filing that looks like a free ride. English is an official language, so a granted European patent needs no translation to take effect there, and plenty of portfolios never touch the Irish office at all. That makes it easy to assume the patent drawings in Ireland you need are simply the sheets you already filed at the EPO. They are not. The Intellectual Property Office of Ireland runs formalities against Rule 12 of the Patents Rules 1992, drafted from the PCT template and never updated to follow the EPO into colour. A set that is legal in Munich can be refused in Kilkenny. Here are the nine rules that decide whether an Irish sheet passes.

Rule 1: Patent Drawings in Ireland Are Optional — Until You Mention Them

The IPOI is blunt about this on its own guidance for the format of a patent application: “The Drawings are not obligatory.” Section 18 of the Patents Act 1992 lists the drawing as a component of a specification only where one is needed. There is no Irish equivalent of the US position in 35 U.S.C. § 113, which compels a drawing wherever it is necessary to understand the invention.

That sounds permissive, and for a simple chemical case it genuinely is — Irish practice normally keeps structural formulae inside the description rather than on a drawing sheet. But the permission is narrow. The moment a figure exists, two separate rules attach to it, and both of them are enforced on formalities rather than left to the examiner’s discretion.

The first is Rule 12(2)(i), which requires that reference signs reconcile with the description and claims in both directions. The second is Rule 13(4): where an application contains drawings, the applicant “shall indicate the figure or, exceptionally, the figures of the drawings which he suggests should accompany the abstract when the abstract is published”. The Controller may override that choice and publish a different figure if it better characterises the invention.

Timing is the part that costs money. Under section 23(1) a drawing filed after the application can move the date of filing to the later date. Rule 18 then fixes the period for responding, and — this is the detail people miss — that period runs from the date the Office sends out its notification, not from your filing date or your docketed priority date. Treat an Irish drawing omission as a date-of-filing problem, not a formality to clean up at your convenience.

Rule 2: Rule 12 Is the Whole Formal Code, and It Is Not 37 CFR 1.84

Everything about the physical form of an Irish sheet sits in a single provision: Rule 12 of the Patents Rules 1992, as amended (the margin figures come through the Patent (Amendment) Rules 2009). There is no Irish MPEP, no multi-page drawing standard, and no office-level design guide of the kind the USPTO publishes. Rule 12 is three subsections long and it is the entire code.

Rule 12(1) sets the sheet. Drawings “shall be on sheets the usable surface area of which shall not exceed 26.2 cm x 17 cm”, and those sheets “shall not contain frames round the usable or used surface”. The minimum margins are top 2.5 cm, left side 2.5 cm, right side 1.5 cm and bottom 1.0 cm.

Read those numbers against 37 CFR 1.84(g) and something useful appears. The US rule requires “a top margin of at least 2.5 cm, a left side margin of at least 2.5 cm, a right side margin of at least 1.5 cm, and a bottom margin of at least 1.0 cm”, leaving “a sight no greater than 17.0 cm by 26.2 cm” on A4. The four margins and the resulting usable area are identical, because both texts descend from the same PCT template. Our note on USPTO drawing requirements under 37 CFR 1.84 works through the US side in detail.

The practical consequence is that the sheet geometry of a compliant US utility set transfers to Ireland without re-laying anything out, and 37 CFR 1.84(f) matches Rule 12(1) on frames as well. What does not transfer is everything in the next rule. Do not let the shared geometry persuade you the two standards are interchangeable; the overlap stops at the page edge.

Rule 3: Black Lines Only — Ireland Did Not Follow the EPO Into Colour

This is the rule that catches well-run portfolios, and it is worth quoting in full. Rule 12(2)(a): drawings “shall be executed in durable, black, sufficiently dense and dark, uniformly thick and well defined, lines and strokes without colourings”.

Those last two words are the operative ones. Rule 12 contains no colour exception, no petition route, and no photograph provision at all. Where 37 CFR 1.84(a)(2) lets the USPTO accept colour in a utility application “only after granting a petition filed under this paragraph explaining why the color drawings are necessary”, and 37 CFR 1.84(b)(1) treats photographs as “not ordinarily permitted” but admissible where they are “the only practicable medium”, Rule 12 simply does not contemplate either. There is nothing to petition.

The EPO moved in the opposite direction. Rule 46 EPC, which used to carry the form requirements for drawings, was deleted with effect from 1 February 2023. The presentation requirements now live in a Decision of the President published in the Official Journal — which is precisely what allowed the EPO to change practice without amending the Implementing Regulations.

From 1 October 2025 the EPO accepts drawings filed electronically in colour or greyscale (Decision of the President, OJ EPO 2025, A49; Notice, OJ EPO 2025, A57), provided they are sufficiently rich in contrast and clear at 300 dpi. It applies to drawings only, and to electronic filings only. If you still cite Rule 46 EPC as live law, read our note on EPO colour patent drawings before your next filing.

So the gap is real and it is new. A colour figure set that is now entirely proper at the EPO is not filable as-is for a direct Irish national application or an Irish short-term patent, because Rule 12(2)(a) still says “without colourings”. The PCT has not moved either: Rule 11.13(a) continues to require black lines “without colorings”, which is why our PCT drawing requirements guide still treats greyscale conversion as the default step.

The working rule for anyone filing patent drawings in Ireland is therefore simple: keep a black-line master. Let the EPO colour set be the derivative, not the source. Reversing that order means re-drafting under time pressure when the Irish or PCT copy is due.

Rule 4: The Two-Thirds Reduction Test Decides Your Line Weight

Rule 12(2)(c) does not give a line thickness in millimetres. It gives a test: the scale and the distinctness of graphical execution “shall be such that a photographic reproduction with a linear reduction in size to two-thirds would enable all details to be distinguished without difficulty”.

That is a functional standard, and it is stricter in practice than a numeric one, because it scales with how crowded your figure is. A clean mechanical elevation survives a two-thirds reduction at a hairline weight. A dense circuit schematic with forty reference signs does not. The honest way to apply Rule 12(2)(c) is to print the sheet at two-thirds and look at it — which is exactly what the drafter intended.

The same subsection adds a trap for anyone who likes to annotate: “If, as an exception, the scale is given on a drawing, it shall be represented graphically.” A written ratio such as “1:2” on the sheet is non-compliant. A graphic scale bar is what the rule asks for, and the word “exception” signals that no scale indication at all is the norm.

Two neighbouring provisions finish the picture. Rule 12(2)(e) requires that all lines “shall, ordinarily, be drawn with the aid of drafting instruments” — the Irish text’s way of excluding freehand work, which in modern practice means a vector tool rather than a sketch or a traced bitmap. Rule 12(2)(f) requires elements of the same figure to be in proportion to each other “unless a difference in proportion is indispensable for the clarity of the figure”. If you break proportion deliberately, make the reason visible in the figure, because the rule puts the burden of necessity on you.

Rule 5: Reference Signs Must Reconcile in Both Directions

Rule 12(2)(i) is the provision most likely to generate an actual objection, and it is symmetrical: reference signs “not mentioned in the description and claims shall not appear in the drawings, and vice versa”. It then adds that the same features, when denoted by reference signs, “shall, throughout the application, be denoted by the same signs”.

Both halves matter. An orphan numeral on a sheet that no longer appears in the text is a defect. So is a numeral discussed in the description that is nowhere on any figure. The second failure is the common one, and it is usually introduced by amendment rather than by drafting — a claim is narrowed, a feature is described in more detail, and the figure is never updated to match.

Rule 12(2)(d) controls how the signs look: all numbers, letters and reference signs “shall be simple and clear”, and “brackets, circles or inverted commas shall not be used in association with numbers and letters”. Circled callouts are a standard convention in engineering drawings and in some national practices. On an Irish sheet they are prohibited. Rule 12(2)(g) then sets the floor: the height of numbers and letters “shall not be less than 0.32 cm”, with the Latin and, where customary, Greek alphabets to be used.

That 0.32 cm is the same minimum as 37 CFR 1.84(p)(3), which requires reference characters to “measure at least .32 cm. (1/8 inch) in height”. Another shared PCT inheritance — and another reason to build one reference-sign table per family and generate every national set from it. Our guide to patent drawing reference numerals sets out how to keep that table authoritative across jurisdictions.

Rule 6: Hatching Must Not Bury the Reference Signs

Rule 12(2)(b) is one sentence and it reverses a habit: cross-sections “shall be indicated by hatching which should not impede the clear reading of the reference signs and leading lines”.

Note which way the priority runs. The hatching is subordinate to the legibility of the signs, not the other way round. A draughtsman trained to show material type through dense, closely spaced hatching is optimising for the wrong thing under Irish practice. Where the two conflict, open the hatch spacing or break it around the numeral and its leader.

There is no prescribed hatch pitch, angle or material-coding convention in Rule 12, which means an examiner cannot object to your hatching style as such. The only ground of objection is the one the rule states: that the hatching has made a reference sign or a leading line hard to read. That makes this an easy defect to self-check — look at every numeral sitting inside a hatched region and ask whether it reads cleanly at two-thirds size, which ties Rule 12(2)(b) directly back to the Rule 12(2)(c) reduction test.

Sectional views carry their own drafting discipline beyond the hatching itself, including where the cutting plane is indicated and how it is labelled; we cover that groundwork in our note on patent drawing sectional views.

Rule 7: Text on a Sheet Is Almost Always a Defect

Rule 12(2)(j) states that drawings “shall not contain text matter, except, when absolutely indispensable, a single word or words such as ‘water’, ‘steam’, ‘open’, ‘closed’, ‘section on AA’, and, in the case of electric circuits and block schematic or flow sheet diagrams, a few short catch words indispensable for understanding”.

The default is no text. The first exception is a handful of single words, and the illustrative list is instructive: they are all state or orientation labels that a reference numeral genuinely cannot carry. “Absolutely indispensable” is a high bar, and anything that could instead be a numeral in the reference-sign table should be a numeral.

The second exception is wider but bounded. Electric circuits, block schematics and flow sheets may carry “a few short catch words”. This is where software, control-system and process-chemistry cases live, and it is the provision that makes a flowchart filable at all — because Rule 12(3) confirms that “flow sheets and diagrams are considered as drawings”, so they are inside Rule 12 rather than outside it.

The limit is “a few short catch words”, not labelled boxes containing sentences. A block diagram whose boxes read “Determine whether the received token matches the stored credential” is outside the exception. Compress each box to a catch word and move the sentence into the description, keyed to the numeral.

One further consequence is worth planning for. Because English is an official language of Ireland, the catch words you are permitted do not create the translation exposure they would in a non-English jurisdiction — but they will if the same sheet is reused for a national filing elsewhere. Keeping text to the Rule 12(2)(j) minimum is what makes a sheet portable.

Rule 8: Figure Numbers and Sheet Numbers Are Separate Systems

Rule 12(2)(h) is the longest limb of the rule and it governs layout. Several figures may share a sheet. Where figures drawn on two or more sheets are intended to form one whole figure, they “shall be so arranged that the whole figure can be assembled without concealing any part of the partial figures”.

Figures must be “arranged without wasting space, preferably in an upright position, clearly separated from one another”. Where they are not upright, “they shall be presented sideways with the top of the figures at the left side of the sheet”. That orientation convention is specific and it is testable — a landscape figure rotated the other way is non-compliant, however legible it is.

Then the part that generates renumbering work: the different figures “shall be numbered consecutively in arabic numerals, independently of the numbering of the sheets”. Figure numbering and sheet numbering are two independent sequences. Rule 15 handles the sheet side, requiring that all sheets of drawings be numbered consecutively as a separate series from the specification sheets.

In practice this is where a late-added figure causes the most damage, because inserting Figure 4 into a set of nine forces a renumber of five figures, every reference to them in the description, and the Rule 13(4) abstract-figure designation — while the sheet numbers may not move at all. Append rather than insert wherever the disclosure allows it. Our note on patent drawing figure numbering works through the sequencing in more depth.

Rule 9: Amendments Need Red Ink, and the Route Into Ireland Shapes the Sheet

Irish amendment practice is formal in a way that surprises people. Rule 31(1) lets an applicant amend the description, claims and drawings of their own volition once, before the time for amendments under sections 29 and 30. After that, a voluntary amendment “may only be made with the consent of the Controller following the filing of an application for leave to amend”.

Rule 31(3) then sets the form: a request to amend must state the reasons for the amendment and be accompanied by a copy of the description, claims or drawings “showing the desired amendment in red ink”, plus the prescribed fee. Rule 31(4) adds that the Controller may require a fresh set of drawings prepared in accordance with Rules 10, 11, 12 and 15. Budget for a clean replacement set, not a marked-up one, whenever a drawing amendment is substantive.

Which rule you are working under depends on how you reached Ireland, and there is one route that no longer exists. Ireland has closed its PCT national route — an international application cannot be taken into a direct Irish national phase, so the PCT reaches Ireland only through the EP regional phase at the EPO, engaged within 31 months. The PCT Applicant’s Guide national chapter for Ireland is the authority to check before you docket anything else.

Ireland is an EPC contracting state, so the mainstream route is a European patent taking effect there, and because English is both an EPC official language and an official language of Ireland, no translation of the specification is required to validate — the point we develop in validating a European patent in Ireland. Rule 12 does not govern that sheet; the EPO’s own presentation requirements do, which is why the colour divergence in Rule 3 above only bites on the national routes.

Those national routes still matter. A direct Irish application, and the Irish short-term patent — up to 10 years from filing, requested on Form No. 1 under Rule 44 — are both Rule 12 filings, and the short-term patent is the option foreign applicants most often overlook. For the filing mechanics around it, see how to file a patent in Ireland.

One enforcement point closes the loop, because it determines what your figures will eventually be read against. Ireland signed the UPC Agreement but has not ratified it — ratification requires a constitutional referendum — so there is no Irish UPC division, and patent proceedings are heard in the High Court in Dublin, usually in the Commercial Court list.

A figure set drafted only to clear formalities, with no thought to how a reference sign maps onto a claim limitation, is the one that disappoints in Dublin; our note on IP enforcement in Ireland covers that forum in detail. Regional context for the jurisdiction sits on our Ireland IP services hub, and we prepare sheets locally for filers in Dublin.

Get an Irish Figure Set That Clears the IPOI First Time

PerspireIP prepares patent drawings in Ireland alongside the US, EPO and PCT versions of the same family, so one invention does not become four inconsistent figure sets with four different reference-sign tables. We work from CAD files, photographs or hand sketches.

See our patent drawing services, or send us the specification and we will tell you what the Irish sheets need before the formalities examiner does.

Frequently Asked Questions