Table of Contents
Most filers treat Spain as a formality stop on the way out of the EPO, and most of them are wrong about one thing in particular: patent drawings in Spain may be filed in colour. The OEPM has said so in its own regulation since 2017, while the USPTO still makes you petition for the privilege. That divergence — plus a quietly brutal rule about text inside figures — is why one figure set sails through Madrid and stalls in Alexandria. Here is what the Annex to Royal Decree 316/2017 requires, where it departs from 37 CFR 1.84 and the EPC, and what the October 2025 colour change means for a Spanish validation.
\n\n\n\nWhich rules govern patent drawings in Spain
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Spanish substantive patent law is Ley 24/2015, de 24 de julio, de Patentes, in force since 1 April 2017. But the rules that decide whether your sheets are accepted are not in the Act. They sit in Article 8 and the Annex to Real Decreto 316/2017, the implementing regulation. There is no Spanish MPEP and no standalone drawing manual: the Annex is the whole code, and it runs to a single lettered list.
\n\n\n\nArticle 8 also settles a question that trips up software and process filings: flow diagrams and schematic process diagrams count as drawings. If your application discloses a method as a flowchart, that flowchart is a figure and is judged by the Annex, not by the text rules.
\n\n\n\nThe Annex opens with page design, and these numbers apply to the application documents as a whole:
\n\n\n\n- Format: A4
- Margins: 35 mm top, 25 mm left, 25 mm right, 20 mm bottom
- Page numbering: consecutive, starting at page 2, bottom and centred
- Line numbering: in the description and claims, on the left, restarting each page at intervals of 5
- Type: Arial 11 at 1.5 line spacing — but Arial 9 at single spacing for translations of European patent claims or specifications
Note the last item. Spain writes its European-patent translation typography straight into the Annex, which tells you how routinely the OEPM handles validations.
\n\n\n\nThe Annex does not set a separate margin table for drawing sheets. It does impose one hard geometric rule: drawing sheets must carry no frame, neither around the useful surface nor around the surface actually used. If your CAD template draws a border or a title block, delete it. Where the same figures are also destined for the EPO or an international application, build them to the PCT Rule 11.13 sight of 26.2 cm by 17 cm with 2.5 cm top and left, 1.5 cm right and 1 cm bottom margins — that geometry satisfies Spain, the EPO and PCT drawing requirements at once.
\n\n\n\nSpain allows colour. The USPTO makes you ask
\n\n\n\nAnnex paragraph (d) is the sentence worth memorising: drawings must be executed in lines and strokes, negros o en color — black or in colour — and well defined. Colour is not an exception in Spain, not a petitionable favour, and not limited to designs. It is one of two ordinary options.
\n\n\n\nCompare the United States. Under 37 CFR 1.84(a)(1) the default is black ink. Under 37 CFR 1.84(a)(2), colour drawings are permitted outright in design applications; in a utility application colour is allowed only “on rare occasions” as the only practical medium, and only after the Office grants a petition. That petition needs:
\n\n\n\n- the fee set out in 37 CFR 1.17(h);
- one set of colour drawings if filed through the USPTO patent electronic filing system, or three sets if not; and
- an amendment inserting this language as the first paragraph of the brief description of the drawings: “The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.”
Photographs diverge too. 37 CFR 1.84(b)(1) says photographs are “not ordinarily permitted” in utility and design applications and are accepted only where they are the only practicable medium — the rule lists cells, histological tissue cross sections, crystalline structures and the like. Where a drawing could do the job, the examiner may demand one. For design filings, remember that 37 CFR 1.152 additionally requires a sufficient number of views to constitute a complete disclosure, and that photographs and drawings must never be combined in the same design application.
\n\n\n\nSo one invention, three answers on colour. Our guide to colour patent drawings works through the petition mechanics in detail.
\n\n\n\nWhere the EPC now sits, and why Rule 46 is not your answer
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If a checklist tells you your figures must satisfy “Rule 46 EPC”, that checklist is out of date. Rule 46 EPC and Rule 49(3) to (12) EPC were deleted with effect from 1 February 2023, as part of the Administrative Council’s digital-transformation package. The form requirements for drawings moved into a Decision of the President of the EPO published in the Official Journal, precisely so that presentation rules can change without amending the Implementing Regulations.
\n\n\n\nThat mechanism was used almost immediately. From 1 October 2025 the EPO accepts drawings filed electronically in colour or greyscale, provided they are contrast-rich and clear at 300 dpi. Description, claims and abstract stay black and white; only the drawings changed.
\n\n\n\nThe PCT did not follow. PCT Rule 11.13(a) still requires drawings in durable, black, sufficiently dense lines “without colorings”. For a Euro-PCT case the EPO will work from colour only where the colour drawings are on PATENTSCOPE and the international publication reflects them. Our EPO drawing requirements explainer tracks the current position.
\n\n\n\nThe Spanish consequence is concrete, and the OEPM has published it: where a European patent has been granted and published by the EPO with colour or greyscale drawings, the OEPM will require the drawings to be submitted in colour or greyscale on validation. Colour is no longer merely permitted in Spain in those cases — it is what the office expects.
\n\n\n\nThe text-in-figures rule that decides your Spanish translation
\n\n\n\nAnnex paragraph (n) is the most practically expensive rule in the whole list. Drawings must contain no text at all, with a closed set of exceptions: brief indispensable indications such as agua, vapor, abierto, cerrado, corte según AB, and, for electrical circuit schematics, installation schematics and diagrams of process steps, the keywords indispensable to understanding them.
\n\n\n\nThen comes the clause that should shape your drafting: those words must be placed so that they can be replaced by their translation without covering any line of the drawings.
\n\n\n\nRead that as a layout instruction, because that is what it is. Spanish is routinely longer than English — “open” becomes “abierto”, “cross-section along AB” becomes “corte según AB”. A label tucked tightly against a lead line in English will overrun a lead line in Spanish. The fix is cheap at drafting time and expensive later: leave horizontal clearance around every in-figure label, anchor labels outside the body of the drawing with short lead lines, and never set text in a box that is sized to the English string.
\n\n\n\nParagraph (ñ) and (o) finish the job: weights and measures in the metric system, temperatures in degrees centigrade, and other physical units per international practice. If another system is used, the metric equivalent must appear as well.
\n\n\n\nReference signs, figure numbers and a punctuation ban
\n\n\n\nThree Annex paragraphs govern the numbering layer, and all three are routinely breached by figure sets imported from US practice.
\n\n\n\n(l) Figure numbering. Figures must be numbered consecutively in Arabic numerals, independently of the numbering of the sheets. FIG. 1 may well sit on sheet 3. Do not restart figure numbers per sheet, and do not compound them into sheet-figure pairs.
\n\n\n\n(m) Reference signs. Reference signs may be used in the drawings only if they appear in the description and in the claims, and vice versa. The reciprocity is the trap: a numeral you added to a figure late in drafting, which never made it into the claims, is a formal defect. The Annex adds that reference signs for the same element must be identical throughout the application — one element, one numeral, everywhere.
\n\n\n\n(g) Punctuation. All figures, letters and reference signs must be simple and clear, and parentheses, circles and quotation marks may not be used in combination with numerals and letters. That outlaws the circled callout, which is a default in a lot of CAD and illustration templates. It also means you cannot bracket a reference numeral in the figure the way you would in a European claim.
\n\n\n\nIf reference numerals are where your objections usually come from, our note on patent drawing reference numerals covers the same discipline across offices.
\n\n\n\nLine quality, hatching and the two-thirds test
\n\n\n\nSpain does not publish a lettering-height table or a line-weight chart. It publishes a performance test instead, and it is stricter than it first looks.
\n\n\n\n(f) The reduction test. The scale and graphic clarity of the drawings must be such that a photographic reproduction with linear reduction to two-thirds still allows every detail to be distinguished without difficulty. Reduce your sheet to 66% and read it. If a hairline vanishes or two adjacent hatch sets merge, the sheet fails, whatever its nominal line weight. The same paragraph adds that where, exceptionally, a drawing’s scale is indicated, it must be represented graphically — a scale bar, not the text “1:50”.
\n\n\n\n(e) Hatching. Sections are indicated by oblique lines that must not impede easy reading of the reference signs and the lead lines. Dense hatching that swallows a numeral is a defect even though the hatching itself is correct.
\n\n\n\n(d), (h) and (i). Lines and strokes must be well defined; all lines should as far as possible be drawn with technical drawing instruments; and elements within a single figure must keep proper proportion to one another unless a difference in proportion is indispensable to the figure’s clarity. That last clause is the authority for an enlarged detail view — use it deliberately rather than quietly rescaling one component.
\n\n\n\nSheet layout and figure orientation
\n\n\n\n(j) One orientation per sheet. A single sheet may carry several figures, but they must all share the same orientation, vertical or horizontal. Where figures drawn across several sheets are intended to constitute one overall figure, they must be arranged so the composite can be assembled without any part of the component figures being concealed.
\n\n\n\n(k) Arrangement. Figures should preferably be arranged vertically on one or more sheets, clearly separated from one another but without wasted space. Where figures are not arranged vertically they must be presented horizontally, with the top of the figures on the left-hand side of the sheet. Landscape figures rotated the other way are a formal defect, and it is an easy one to make when exporting from CAD.
\n\n\n\n(a) Document order. Each part of the application starts on a new page headed DESCRIPCIÓN, REIVINDICACIONES and, where present, DIBUJOS Y LISTA DE SECUENCIAS, RESUMEN — centred, upper case and bold. Drawings are a separately headed part of the filing, not an appendix to the description.
\n\n\n\nValidation, enforcement, and nine checks before you file
\n\n\n\nSpain is an EPC contracting state, so a European patent reaches Spain by validation. Spain is not a party to the London Agreement, so the concession other states grant does not apply: to validate, the proprietor must file a full Spanish translation of the granted text — description, claims and drawings — within three months of the date on which the mention of the grant, or of the decision to maintain the patent as amended, is published in the European Patent Bulletin. This is where paragraph (n) and the Arial 9 typography rule come due at the same time.
\n\n\n\nSpain is also not a Unified Patent Court state. It never joined, so there is no unitary route into Spain and no UPC division will hear a Spanish infringement case. Enforcement stays resolutely national, and it is concentrated:
\n\n\n\n- Specialised patent judges sit in Barcelona, Madrid and Valencia only.
- In Barcelona, Commercial Courts 1, 4 and 5 have exclusive jurisdiction over patent and design claims — a specialisation in force since 1 January 2012 — while courts 2, 6, 8 and 9 take trademark cases.
- Appeals in IP cases go to Section 15 of the Audiencia Provincial de Barcelona, which has held exclusive competence over intellectual property appeals since 1993.
- Most Spanish patent infringement claims are filed in Barcelona, which is why a figure set that has to survive litigation should be built to survive a Barcelona reading.
If the filing is local, our patent drawing team in Madrid and in Barcelona work to the Annex as a matter of course, our wider patent drawing services cover the EPO and PCT routes into the same family, and the IP services in Spain page sets out the rest.
\n\n\n\nNine checks that catch almost every OEPM formal objection:
\n\n\n\n- A4 sheets, and no frame around the useful or used surface.
- Lines black or colour — but matched to the office you are actually filing in.
- Figures numbered consecutively in Arabic numerals, independent of sheet numbers.
- Every reference sign present in both the description and the claims, and identical throughout.
- No parentheses, circles or quotation marks combined with numerals or letters.
- No text in the figures beyond the indispensable, and positioned to accept a longer Spanish translation without covering a line.
- The sheet still legible when reduced to two-thirds; any scale shown graphically.
- One orientation per sheet; horizontal figures with their top at the left edge.
- Metric units and degrees centigrade throughout.
Run these before the filing goes out and the Annex stops being a risk. Run them after a notification of defects and you are paying for the same sheets twice.
\n\n\n\nHow PerspireIP Can Help
\n\n\n\nAt PerspireIP, our team helps innovators and businesses protect what they build. Whether you need a patent or trademark search, prior-art analysis, or an IP strategy tailored to your goals, we can help. Contact our team to discuss your next step.
\n\n\n\nFrequently Asked Questions
\n\n\nCan patent drawings in Spain be filed in colour?
Yes. Paragraph (d) of the Annex to Real Decreto 316/2017 requires drawings to be executed in lines and strokes that are black or in colour, and well defined. Colour is an ordinary option in Spain, not a petitionable exception as it is for a US utility application.
Does Spain accept photographs as patent drawings?
The Annex to RD 316/2017 is written around lines and strokes rather than photographs, so a photograph should not be relied on as a formal figure without checking current OEPM practice for the specific case. The safer course, as at the EPO and the USPTO, is a line drawing wherever the subject matter admits of one.
Is Rule 46 EPC still the standard for drawings in Europe?
No. Rule 46 EPC was deleted with effect from 1 February 2023, along with Rule 49(3) to (12) EPC. The form requirements now sit in a Decision of the President of the EPO, and since 1 October 2025 the EPO accepts electronically filed colour and greyscale drawings.
How long do I have to validate a European patent in Spain?
Three months from publication of the mention of grant, or of the decision to maintain the patent as amended, in the European Patent Bulletin. Spain is not a London Agreement party, so a full Spanish translation of the description, claims and drawings is required.
Is Spain part of the Unified Patent Court?
No. Spain never joined the UPC or the unitary patent, so there is no unitary effect in Spain and no UPC division hears Spanish cases. Infringement is litigated nationally, overwhelmingly before the specialised commercial courts in Barcelona.
Do flowcharts count as drawings at the OEPM?
Yes. Article 8 of RD 316/2017 treats process flow diagrams and schematic diagrams as drawings, so a method disclosed as a flowchart is judged against the Annex formalities, including the restriction on text inside figures.