Patent drawings get rejected for the strangest reasons. A line slightly too thin. A reference number a millimeter too small. A view labeled with the wrong abbreviation. None of it is mysterious — it is all written down in 37 CFR 1.84, the federal regulation that tells the USPTO what a patent drawing must look like. The problem is that the regulation is dense, the formatting matters, and one missed detail can trigger an office action that costs weeks of pendency.
This guide walks through every subsection of 37 CFR 1.84 in plain English, with three visual infographics, a common-mistakes table, and the kinds of practical details that don’t make it into the regulation text itself. It is written for inventors, paralegals, patent attorneys, and patent illustrators — anyone who has to make a drawing that survives examination on the first pass.
- Table of Contents
- What 37 CFR 1.84 Actually Is
- Paper Size, Margins, and Sheet Layout
- Views, Arrangement, and Scale
- Lines, Shading, and Reference Characters
- Numbering, Legends, and Notices
- Color Drawings and Photographs
- Common Mistakes and How to Avoid Them
- How PerspireIP Handles 37 CFR 1.84 Compliance
- Frequently Asked Questions
What 37 CFR 1.84 Actually Is
37 CFR 1.84 — formally Title 37, Code of Federal Regulations, Section 1.84, “Standards for drawings” — is the rulebook the USPTO uses to evaluate every patent drawing submitted with a U.S. patent application. The regulation runs from subsection (a) through (x). Most of it deals with mechanical details: paper, margins, line weight, view types, reference numbers. The underlying logic is reproducibility. A patent drawing has to survive being scanned, reduced, photocopied, and printed in the published patent without losing clarity. Every requirement traces back to that goal.
The regulation lives under the broader Manual of Patent Examining Procedure (MPEP), specifically MPEP § 608.02, which examiners use day-to-day. If a drawing fails 37 CFR 1.84, the USPTO issues a Notice of Draftsperson’s Objection or a formal office action requiring corrected drawings. That delay typically adds two to four months of pendency. Worse, it sometimes leads to non-compliant drawings being entered into the file wrapper and creating ambiguity for the rest of the patent’s life. Getting it right the first time is dramatically cheaper than fixing it later — see our guide on patent drawing mistakes that trigger office actions.
The official text lives in the Electronic Code of Federal Regulations. The USPTO’s MPEP § 608.02 is the practical companion. Together they govern utility, design, plant, and reissue applications — with a few specialized variations for design and plant drawings.
Paper Size, Margins, and Sheet Layout
Subsections (e), (f), (g), and (x) of 37 CFR 1.84 govern the physical sheet itself. They are the easiest rules to comply with and somehow the easiest to get wrong.
Paper itself — 37 CFR 1.84(e). Drawings must be on white, smooth, non-shiny, durable paper, used only on one side. For electronic filing via EFS-Web or Patent Center, the equivalent is a clean PDF or TIFF without watermarks, headers, footers, or background colors. The “non-shiny” requirement carried over from the era of paper scanning, and remains the basis for rejecting drawings with gradients or photographic-style finishes that scan poorly.
Paper size — 37 CFR 1.84(f). Two sizes are accepted: DIN A4 (21.0 × 29.7 cm) or US Letter (21.6 × 27.9 cm). All sheets in a single application must be the same size. Mixing A4 and Letter sheets in one application is a formal objection.
Margins — 37 CFR 1.84(g). Top 2.5 cm, left 2.5 cm, right 1.5 cm, bottom 1.0 cm. All four margins must be free of figures, reference characters, page numbers, signatures, and frames. The space inside these margins — the “sight” — is the drawing area. Letter sheets give you 17.6 × 24.4 cm of sight; A4 gives you 17.0 × 26.2 cm. Designers used to print frames around drawings; that practice is now non-compliant unless the frame sits inside the sight area (and most examiners flag it anyway).
No holes — 37 CFR 1.84(x). Drawing sheets cannot contain punched binding holes. A simple requirement, occasionally violated by inventors who file pro se and three-hole-punched their sheets before scanning.
Views, Arrangement, and Scale
Subsections (h) through (k) of 37 CFR 1.84 govern what kinds of views are allowed, how they fit on the sheet, and how big the drawings need to be.
View types — 37 CFR 1.84(h). Four primary types are permitted: plan (top-down), elevation (side-on), sectional (cut-through with hatched cut faces), and perspective (3D). Subsections (h)(2) through (h)(5) authorize derivative views: exploded views to show assembly relationships, partial views for large objects that don’t fit on a single sheet, enlarged views to show detail, and broken-out views to expose internal structure without a full section. Each derivative view has its own labeling conventions — for example, partial views must be tied together with reference letters in a key figure.
Arrangement of views — 37 CFR 1.84(i). Views must be arranged on the sheet so the sheet can be read with its short side at the top (portrait) or, if necessary, with one side at the top and the figure rotated 90°. Multiple figures on the same sheet must not overlap. Each figure stands as a separate, complete unit.
Front-page view — 37 CFR 1.84(j). Each application must identify one figure as the lead — the one most representative of the invention — that the USPTO publishes on the front page of the patent. Choosing the right lead figure matters more than founders realize: it is the figure search engines and competitors see first.
Scale — 37 CFR 1.84(k). The drawing must be large enough that every detail remains legible when the drawing is reproduced at two-thirds size — the size the USPTO uses for publication. The “reduce to 67% and check legibility” test is the practical interpretation. Notations such as “scale 1:1” or “actual size” are not allowed.
Lines, Shading, and Reference Characters
This is the section where most office actions originate. Subsections (l), (m), (n), (p), (q), and (r) cover the tactile look of the drawing — line weight, shading, reference number sizing, lead lines, arrows.
Character of lines — 37 CFR 1.84(l). All lines, numbers, and letters must be durable, clean, black, sufficiently dense and dark, uniformly thick, and well-defined. Every line must be the same density. This is what kills pencil drawings, faint ink, and photocopied bitmap art. Lines should be solid black. The regulation specifically calls out that “fine or crowded lines” are vulnerable when reduced to two-thirds size. A drawing that looks fine at full size and turns into a blur at 67% will fail.
Shading — 37 CFR 1.84(m). Shading is permitted and encouraged for indicating surface and contour, but the technique is restricted. Acceptable shading is parallel lines of consistent thickness, with sufficient open space to allow legibility under reduction. Solid black shading is generally prohibited except for very small areas where contrast is essential. Hatch lines for sectional views must not overlap or run together. Photographic-style continuous-tone shading (the kind a software renderer produces by default) is rejected categorically.
Symbols — 37 CFR 1.84(n). Graphical symbols (electrical schematics, fluid power symbols, etc.) are permitted when they are universally understood in the relevant field and used in their standard form. Custom symbols must be defined in the specification.
Numbers, letters, reference characters — 37 CFR 1.84(p). The most-cited subsection. Reference characters must be at least 0.32 cm (⅛ inch) in height. Arabic numerals are preferred over Roman. The same reference character must always refer to the same part across all figures. Reference characters must not be enclosed in circles unless that is required for clarity. They must not be placed in margins or so close to other features that they cannot be read clearly. They should be oriented in the same direction as the view itself, so the reader does not have to rotate the page to read them.
Lead lines — 37 CFR 1.84(q). Lead lines are the lines connecting a reference character to the feature it identifies. They must be as short as practicable, must not cross each other, and must end on the feature they identify. They cannot be in the same direction as nearby hatching, because that visually merges with the hatching and confuses the reader. Lead lines may be straight or slightly curved but not freehand-scribbled.
Arrows — 37 CFR 1.84(r). Arrows are used for three purposes: at the end of lead lines to point to a feature, on a lead line to indicate direction of motion or rotation, and on view-direction indicators (section arrows, view arrows). Their use is restricted to these purposes — decorative arrows are not permitted.
Numbering, Legends, and Notices
Subsections (c), (o), (s), (t), (u), (v), and (w) cover labeling and administrative markings on the sheet itself.
Identification of drawings — 37 CFR 1.84(c). Drawings submitted with an application can include identification information (applicant name, application number or docket number) at the top of the sheet, within the top margin but not in the sight. This helps the USPTO route the drawings correctly. Once the application has a serial number, the serial number is included on each sheet.
Legends — 37 CFR 1.84(o). Suitable descriptive legends may be used to enhance understandability of the drawing. Subject to USPTO approval, legends like “PRIOR ART,” “CROSS-SECTION ALONG A-A,” and “SECTION B-B” are permitted. Legends should be in English. They must be lettered in the same style and size as the reference characters.
Copyright or mask work notice — 37 CFR 1.84(s). The USPTO permits a copyright or mask work notice to be placed in the drawing, immediately below the figure represented, within the sight. The size of the notice is limited and the notice must be in language specified by 37 CFR 1.71(d). Many practitioners skip the notice; it is optional but useful for software-related drawings where copyrightable elements may appear.
Numbering of sheets — 37 CFR 1.84(t). Sheets are numbered consecutively in Arabic numerals in the top margin, centered, in the format “1/3, 2/3, 3/3” (sheet number / total sheets). This format is preferred because it confirms completeness — an examiner can see that no sheets are missing.
Numbering of views — 37 CFR 1.84(u). Views must be numbered consecutively, regardless of sheet, in Arabic numerals: FIG. 1, FIG. 2, FIG. 3 … When a single object requires multiple related views, the views can be labeled with the same Arabic numeral plus a letter: FIG. 1A, FIG. 1B, FIG. 1C. The “FIG.” abbreviation is required — not “Figure” or “Fig” or “fig.”
Security markings — 37 CFR 1.84(v). Authorized security markings (for inventions subject to government secrecy orders) may be placed centered at the top of the sight on each sheet. This is rare but well-defined when it applies.
Corrections — 37 CFR 1.84(w). Corrections to drawings must be durable and permanent. The era of strike-throughs and pasted-on corrections is over — modern practice is to refile a corrected drawing. The corrected sheets must be a complete replacement, not a markup.
Color Drawings and Photographs
Subsections (a)(2) and (b) of 37 CFR 1.84 handle the two special cases that everybody asks about: color drawings and photographs.
Color drawings — 37 CFR 1.84(a)(2). Color drawings are not normally accepted. They are accepted only when color is the only practicable medium to disclose the subject matter of the invention — typically biological samples, certain coatings, calibration colors, or specific design patent finishes. To file color drawings, the applicant must submit a petition under 37 CFR 1.84(a)(2)(iii), pay a fee, and include three sets of the color drawings (for paper filings) or follow the digital equivalent. The petition is reviewed and granted or denied separately from the substantive examination. Most utility applications do not need color and should not file in color.
Photographs — 37 CFR 1.84(b). Photographs are likewise not normally accepted, because they reproduce poorly in printed patents and often have ambiguous edges. They are permitted when “they are the only practicable medium for illustrating the claimed invention.” Common acceptable cases include: photomicrographs (electrophoresis gels, histological cross-sections), animal photographs in design patents, and certain ornamental designs in design patents. Black-and-white photographs are preferred when photos are allowed; color photos require the same petition process as color drawings.
Practical advice. Even when a photograph would be technically acceptable, most experienced practitioners convert it to a line drawing where possible. Line drawings reproduce cleanly, scale to two-thirds without artifacts, and avoid examiner disputes. The exceptions are biological and medical disclosures where the contour and color are themselves what is being claimed.
Graphic forms — 37 CFR 1.84(d). Chemical or mathematical formulas, tables, and waveforms may be submitted as drawings. They are subject to the same requirements as other drawings. The formula or table is identified as a separate figure with a label.
Common Mistakes and How to Avoid Them
The table below captures the failure patterns we see most often during patent drawing review, with the corresponding 37 CFR 1.84 subsection and a one-line fix.
| Mistake | Subsection | Fix |
|---|---|---|
| Reference numerals smaller than 0.32 cm | (p) | Reset all reference characters to ≥ ⅛” tall |
| Lead lines cross each other | (q) | Reroute lead lines; relocate reference characters |
| Continuous-tone (gradient) shading | (m) | Replace with parallel-line shading |
| Margin violated by figure or number | (g) | Move content inside sight area |
| Mixed paper sizes in one application | (f) | Reissue all sheets in one size (A4 or Letter) |
| Color drawing without a petition | (a)(2) | Convert to black-and-white or file petition + fee |
| “Figure 1” instead of “FIG. 1” | (u) | Use the exact “FIG.” abbreviation |
| Reference character used inconsistently across views | (p) | Audit for consistency — same number = same part |
| Fine lines that disappear under 2/3 reduction | (l), (k) | Increase line weight; test print at 67% |
| Photograph filed without petition | (b) | Convert to line drawing or file petition + justification |
| Punched holes in sheets | (x) | Reprint without binding holes |
| Hatch lines too dense or overlapping | (m) | Increase spacing; align in one direction |
A practical workflow that catches most of these before filing: print every drawing at 67% on plain paper, set it next to the full-size original, and read every reference number with your unaided eye. If a number is fuzzy or a lead line is unclear at 67%, the examiner will see the same thing. Fix it before filing.
How PerspireIP Handles 37 CFR 1.84 Compliance
PerspireIP produces patent drawings keyed to 37 CFR 1.84 from the first stroke. Our patent illustration team works from inventor sketches, CAD files, or product photographs, and delivers utility, design, and PCT drawings that pass formal review on the first submission. Every set is checked against the regulation — paper size, margins, sight area, line weight, shading density, reference character height, lead-line routing, view numbering — before it leaves our hands.
For applicants who already have drawings, we offer compliance reviews and corrections. We pull the existing set, run it against the 37 CFR 1.84 checklist, and return either a clean compliance memo or a corrected set ready to refile. The work pairs naturally with our patent invalidity search and freedom-to-operate services for buyers running IP due diligence on acquisition targets. Talk to us early — fixing drawings before filing costs a fraction of fixing them after an office action.
Conclusion
37 CFR 1.84 is a long checklist, but it is a finite one. Every subsection has a clear rule, and every rule has a clear pass/fail test. The cost of getting it right is small; the cost of getting it wrong is months of pendency and a file wrapper littered with corrections. Inventors, paralegals, attorneys, and illustrators who memorize the most-cited subsections (e, f, g, h, k, l, m, p, q, t, u) eliminate the vast majority of formal rejections. The rest is judgment calls — color vs. black-and-white, photograph vs. line drawing, full view vs. partial — and those judgment calls become easier once the rules underneath are second nature. If your application is approaching filing or your drawings are coming back from the USPTO with objections, contact PerspireIP and we’ll get the work back on the rails.
Frequently Asked Questions
What exactly is 37 CFR 1.84?
37 CFR 1.84 is the U.S. federal regulation that sets formal standards for patent drawings filed with the USPTO. It covers paper, margins, views, lines, shading, reference characters, labels, and a handful of administrative details. Its subsections run (a) through (x).
Is 37 CFR 1.84 enforced for design patents the same way as utility patents?
Mostly yes, with adjustments. Design patent drawings have additional requirements (surface shading, broken-line conventions for unclaimed subject matter) but the underlying formal standards — paper, margins, line quality — are identical.
Can I use a CAD-generated drawing as my patent drawing?
Yes, provided the export complies with 37 CFR 1.84. Common issues with CAD exports are: thin or pale line weights, photographic-style shading, anti-aliased edges that scan poorly, and reference characters that are too small or use a non-compliant font. A patent illustrator typically post-processes CAD output to bring it into compliance.
What size do reference numerals have to be?
At least 0.32 cm (⅛ inch) tall. Larger is fine; smaller is a formal objection under 37 CFR 1.84(p).
Are color drawings ever accepted?
Yes, but only after a petition under 37 CFR 1.84(a)(2)(iii) is granted and the fee is paid. The petition must show that color is the only practicable medium for the subject matter. Most utility applications do not qualify and should not file in color.
What happens if my drawings fail 37 CFR 1.84?
The USPTO issues a Notice of Draftsperson’s Objection or includes the objection in an office action. The applicant must submit corrected drawings within the response deadline, usually three months extendable to six. Failing to correct can lead to abandonment.
Where does the official text of 37 CFR 1.84 live?
In the Electronic Code of Federal Regulations at eCFR. The USPTO’s MPEP § 608.02 is the examiner-facing companion that explains how the rule is applied in practice.
Do I need a professional patent illustrator, or can I make the drawings myself?
Either is allowed. Pro se applicants regularly file their own drawings. The risk is that small formal issues — line weight, reference number size, shading style — produce objections that are easy and cheap to avoid by having a patent illustrator handle the work from the start.