What Size Type Should You Use for Leather Hot Foil Stamping? A Practical Guide from 3mm to 10mm

A hot foil impression can be perfectly clean and still look wrong.

The temperature was fine. The foil transferred properly. The letters are straight. Nothing has technically gone wrong, yet the finished piece feels a little awkward. Too timid, perhaps. Or too crowded. Maybe the name looks as though it has been squeezed onto the leather at the last minute.

Quite often, the problem is not the foil or the machine.

It is scale.

Choosing brass type is not simply a matter of deciding whether 6mm or 8mm sounds more useful. Letter size changes the whole character of a piece. Three-millimetre type can feel quiet and considered. Ten-millimetre type is much closer to display lettering. It does not just label the work. It becomes part of the design.

And no, smaller is not automatically more refined. Larger is not automatically more readable either.

The useful question is this:

How much visual space should the lettering occupy, and what job is it meant to do?

The quick guide

Here is a practical starting point.

Treat that table as a starting point, not law.

A large luggage tag can look excellent with restrained 6mm lettering and plenty of empty space. A small keyring can carry one oversized 10mm initial rather beautifully. The object itself does not make the decision. The available space, the text and the intended visual hierarchy do.

That distinction matters.

First, what does “6mm type” actually mean?

This is where things get muddled surprisingly quickly.

A physical brass type size is not necessarily the same thing as the point size shown in a design program. In the CÍ and MAXITA ranges, sizes such as 3mm, 6mm and 8mm are commonly measured using the height of the capital letter A. Lowercase letters, numbers and punctuation are then scaled in proportion to the chosen typeface.

Digital typography works differently. Traditional point size is usually based on the typeface’s em box, not simply the visible height of the capital letters. Adobe Illustrator now distinguishes between Em Box, Cap Height and x-Height precisely because two fonts set at the same nominal size can have noticeably different visible proportions.

This means a 6mm Times New Roman capital and a 6mm condensed sans serif capital may share the same height but occupy very different amounts of horizontal space.

One may feel airy and traditional. The other may feel tall, narrow and modern.

So before worrying about whether you need 6mm or 8mm, check what the supplier is actually measuring:

• The visible capital-letter height
• The total height of the metal type
• The size of the brass base
• The engraving depth
• The maximum line width of the holder

They are all different measurements. Unfortunately, they are not always described clearly.

The real measurement is usable space, not product width

Let us say you are making a 70mm-wide leather tag.

That does not give you 70mm for lettering.

Some of that space belongs to the stitching line, edge finish, rounded corners, attachment hole and, most importantly, the margin around the name. Once those are accounted for, your genuinely usable line might be closer to 45 or 50mm.

This is why choosing type by object name is unreliable.

“Type for a wallet” is not a useful measurement. Wallets come in different proportions. Some carry a single initial. Others need a full name, date or company line. The same applies to keyrings, notebook covers and luggage tags.

Start with the text and the usable line.

As a rough workshop rule, we like to leave breathing room around the lettering rather than making the largest possible type fit by a fraction. If the first and last letters are nearly touching the visual margins, the type is probably too large, even when it technically fits.

Leatherwork tends to look better when nothing appears desperate to occupy every millimetre.

3mm type: small, useful and slightly unforgiving

Three-millimetre type earns its place in genuinely restricted spaces.

It works well for:

• Narrow leather goods
• Wallet interiors
• Small dates or edition numbers
• Longer names
• Pencil and pen-related work
• Book spines and compact labels
• A discreet maker’s mark

MAXITA’s small movable type is offered with an A height of approximately 3mm and is presented for narrow applications such as pencil stamping, alongside larger 6mm and 8mm options.

The benefit is obvious. You can fit more information into a smaller area.

The catch is that tiny type asks more from everything around it.

Fine serifs, narrow counters and thin strokes are less forgiving on heavily textured leather. A smooth vegetable-tanned surface may hold the detail beautifully. An oily, deeply grained or very soft surface may interrupt the smaller shapes.

Small type also needs a reason to be small.

Using 3mm in the centre of a large, otherwise empty luggage tag can make the lettering look hesitant rather than elegant. Scale it down because the area or text requires it, not because “small” sounds luxurious.

There is a point where subtle simply becomes difficult to see.

3.5–5mm type: the overlooked sweet spot

This middle range does not get as much attention as 3mm or 6mm, but it makes a great deal of sense for small leather goods.

It is large enough to remain readable, yet restrained enough for:

• Card holders
• Wallet fronts
• Glasses cases
• Passport covers
• Small leather labels
• Two-line layouts
• Secondary brand information

CÍ’s fine brass type range sits between approximately 3.5mm and 5mm in capital height, depending on the typeface. The sets include uppercase and lowercase letters, numbers, punctuation and spacing pieces, with different fonts producing slightly different visible heights and widths.

That variation is not a flaw. It is how type works.

A typeface with a large x-height may make its lowercase letters look surprisingly substantial, even when the capitals are modest. A delicate serif may feel smaller than a plain sans serif with exactly the same capital height.

For makers who mostly work on wallets, card holders and compact personalised pieces, this range often provides more control than jumping straight from 3mm to 6mm.

6mm type: the workhorse

If someone is buying a first general-purpose brass type set, 6mm is usually the sensible place to begin.

Not because it is perfect for everything. Nothing is.

It is simply the size that creates the fewest obvious compromises across common leather projects.

Six-millimetre lettering is clear enough for a notebook cover or keyring, but not so large that a short name immediately takes over a wallet. It can work for:

• Wallets and card holders
• Notebook covers
• Keyrings
• Leather labels
• Small gift items
• Packaging
• Short brand names
• Names and initials

CÍ’s 6mm brass set, for example, is built as a complete 307-piece collection with letters, numbers and symbols, and is positioned for notebooks, wallets, labels and other small leather goods. Multiple typefaces are available, which matters because font width can change the result almost as much as height.

We tend to think of 6mm as body copy for the workbench.

It gets used. It is not especially dramatic, and that is precisely the point.

Where does it struggle? Long wording on narrow pieces. A six-millimetre name made mostly from wide letters, particularly M, W and O, can run out of room much faster than expected. A condensed typeface may solve that. Moving down to 4mm may solve it better.

The right answer is not always to force the preferred size into the holder.

8mm type: when the lettering should be noticed

At 8mm, lettering starts to move away from quiet personalisation and towards a more deliberate graphic element.

It suits:

• Luggage tags
• Larger keyrings
• Notebook and journal covers
• Short brand names
• Monograms
• Large leather labels
• Packaging headlines
• Short names with generous spacing

CÍ’s 8mm set uses larger individual brass pieces and is available as a 307-piece collection. The size of the type also changes the practical side of ownership. A single-layer storage box holds roughly 120 pieces, while a full set of more than 300 pieces requires a larger double-layer box.

That may sound like a storage detail, but it reveals something useful about scale.

Large type needs space everywhere. In the box, in the holder and on the finished work.

Eight-millimetre lettering is often at its best when the text is short. A first name, initials or a compact brand word can look strong without becoming loud. Add a long phrase, two lines and tight margins, and the same type begins to feel heavy.

One clean line usually beats three lines fighting for attention.

10mm type: less like a label, more like a design element

Ten-millimetre type is not really an enlarged everyday size.

It is display type.

Use it when the lettering should carry real visual weight:

• A single initial
• A short first name
• A short word
• A year or number
• A simple symbol
• A large luggage tag
• A notebook cover
• Bold product packaging
• A leather label designed to be seen from a distance

The CÍ 10mm Brass Type Set was developed around that kind of use. It is designed for hot foil stamping and heat embossing on projects such as luggage tags, keyrings, labels, notebook covers and packaging. Each piece has a 3mm engraving depth, intended to help the character press more clearly into softer leather while reducing the likelihood of the brass base marking the surface. It is designed for Maxita Holder No. 1.

That deeper engraving is not there because 10mm lettering needs to be pressed brutally hard. Quite the opposite.

The aim is to give the raised character enough separation from the base, so the letter can reach the leather without the surrounding block joining the party.

Times New Roman is the standard option for the CÍ set, while alternative and custom typefaces can be requested. The pieces are large enough that a traditional metal type tin is not especially practical, so the set comes with a clear compartment box instead.

It is also a new product, so the useful reason to choose it is not a long list of product-specific reviews. Not yet. The decision should come down to whether its scale and construction make sense for the work you actually make.

That is a healthier reason to buy a tool anyway.

Typeface can make one size behave like another

This is the part size charts cannot fully explain.

A 6mm condensed typeface might fit where a 5mm wide serif does not. A 10mm thin Times-style letter can feel more elegant than an 8mm heavy sans serif. A font with a high x-height will make lowercase text appear bigger and more assertive.

The visual result is shaped by:

• Character width
• Stroke weight
• Serif size
• x-height
• Internal counters
• Letter spacing
• Uppercase-to-lowercase proportions
• The number of wide characters in the actual wording

Adobe’s distinction between cap height, x-height and the em box is useful here. It explains why matching a computer point size to physical brass type by simple conversion rarely works cleanly.

There is no universal formula that turns 24pt into “the correct 6mm brass type”.

The best comparison is visual and physical.

The leather changes the answer too

A size that looks crisp on smooth vegetable-tanned leather may feel less defined on a deeply grained surface.

This does not mean textured leather cannot be foil stamped. It means smaller and more delicate details have less margin for error.

In practical terms:

• Fine 3mm serifs generally benefit from a smoother surface
• Medium 4–6mm type handles a wider range of leather finishes
• Larger 8–10mm characters can remain legible on more visible textures
• Very soft leather may require careful control to avoid excessive sinking or base marks
• Blind embossing and foil stamping may produce different visual weight even with the same type

Foil colour matters as well.

A reflective gold line can appear visually stronger than a blind impression in the same size. High contrast makes the lettering feel larger. Low contrast makes it quieter.

This is one reason copying a size from another maker’s photograph is unreliable. Their leather, foil, font, camera angle and lighting may all be doing part of the work.

The simplest test costs almost nothing

Before ordering a full type set, make a paper mock-up.

It is not glamorous. It is extremely useful.

1. Measure the usable area

Ignore the total object size for a moment.

Mark the space remaining after accounting for:

• Stitching
• Edge finishing
• Hardware
• Holes
• Curves
• Fold lines
• Comfortable visual margins

2. Use the real text

Do not test with “ABC”.

Type the actual name, word or phrase you intend to stamp. “WILLIAM” and “LILY” behave very differently, even with the same number of letters.

3. Set the capital height

In software that supports it, size the lettering using cap height rather than relying only on point size. Adobe Illustrator includes a Cap Height option that bases the measurement on the visible uppercase letters.

Make versions at 3mm, 4mm, 6mm, 8mm and 10mm.

4. Print at 100 per cent

Do not resize the page to fit the printer.

Cut out the lines and place them directly onto the leather or a full-size paper model.

5. Step back

Look at the piece from the distance at which it will normally be used.

The version that looked stylish at 300 per cent zoom may suddenly feel tiny. The largest version may look fine on its own, then overwhelming once the stitching and hardware are added.

This ten-minute test is more useful than scrolling through another fifty product photographs.

What makers actually worry about

Online workshop discussions are useful because the questions are rarely abstract.

People are not usually asking which size sounds most premium. They are trying to work out whether small stamped letters will stay clean, whether a particular type set fits their holder, or whether parts and service will still exist after they buy a machine.

In one recent Leathercraft discussion, a maker working with tiny 4mm or 6mm stamped letters found it difficult to add a clean gold finish by hand. The small recessed details left very little room for error.

In other discussions about hot foil equipment, makers repeatedly return to type-holder compatibility, machine support and the availability of replacement parts. One user specifically viewed continued access to advice, parts and service as an advantage when comparing older machines.

These comments are anecdotal, not laboratory evidence. Still, they point towards something product pages often miss.

Buying brass type is not only about the front face of the letter.

It is about the whole system around it.

Before buying, check the boring measurements

The boring measurements are the ones that save money.

Confirm:

• The actual visible letter height
• The total metal type height
• The brass base width and depth
• The engraving depth
• The internal dimensions of the holder
• The maximum line length
• Whether one or more lines can be arranged
• Which spacing pieces are included
• Whether the set contains enough repeated vowels and common letters
• Whether replacement characters can be ordered
• Whether the type is compatible with your existing machine

CÍ’s own ranges illustrate why this matters. The fine 3.5–5mm kit is listed as compatible with several Maxita holders and a number of other machine systems, while the larger 6mm, 8mm and 10mm ranges have more specific holder requirements.

Never assume that two pieces of metal type with the same visible letter height will share the same base or work in the same holder.

Measure first. It is not exciting, but neither is discovering that a beautiful set does not fit.

So, which size should you buy first?

Here is the honest version.

Choose 3mm if:

You mainly work on narrow surfaces, wallet interiors, pencils, small labels, dates or longer lines of text.

Choose 3.5–5mm if:

Your work is mostly wallets, card holders and compact personalised pieces, and you want something refined without making every line difficult to read.

Choose 6mm if:

You make a mixture of small leather goods and want one dependable general-purpose set.

For many workshops, this is the safest first purchase.

Choose 8mm if:

You work on luggage tags, covers and larger labels, and your lettering is usually short enough to carry more visual weight.

Choose 10mm if:

You want the type to act as a design feature. Think initials, short words, bold numbers and generous, uncluttered layouts.

There is no rule saying a workshop needs every size.

In practice, a useful system is often one everyday set and one display set. For example:

• 4mm plus 8mm
• 5mm plus 10mm
• 6mm plus 10mm

One handles ordinary personalisation. The other handles the moments when the lettering deserves to lead.

A final note on CÍ

CÍ is a boutique leathercraft tool store built around a fairly simple idea: good tools should be useful on the bench, not merely attractive in a product photograph.

The business is run between Nuremberg and Shanghai. Some products are developed and produced through CÍ’s own factory, including custom and specialist pieces. Others come from independent tool designers and workshop brands that the team has chosen to work with over time.

That mixed model is deliberate.

A serious leather workshop rarely runs on one brand alone. You may prefer one maker’s pricking irons, another studio’s stitching pony and a completely different system for foil stamping or skiving. CÍ brings those categories together rather than pretending one factory has the perfect answer to every job.

The range now covers hot foil stamping machines, brass type, custom stamps, pricking irons, stitching ponies, skiving equipment, cutting and edge-finishing tools, leather dies, hardware, measuring tools and workshop storage.

Orders over US$50 currently qualify for free global shipping, with fulfilment handled from Germany or Shanghai depending on stock and destination.

For supported machines, CÍ provides one year of free after-sales service for covered issues. The modular construction of machines such as the Maxita EC-17 and EC-27 means that a replacement component can often be sent without requiring the entire machine to be returned. Technical support remains available after the first year, with parts charged separately where required.

The website currently displays 506 verified reviews from makers worldwide, with an overall rating of 4.91 out of 5. Reviews on the Maxita EC-27 page repeatedly mention clear communication, careful packaging, solid construction and responsive support.

That does not mean every tool is right for every maker.

It does mean there is a visible track record behind the shop, and a team still there after the parcel has arrived.

Which, when you are buying equipment for real workshop use, matters rather more than another glossy product claim.

Frequently asked questions

Is 6mm type too large for a wallet?

Not necessarily. It works well for a short name, initials or a restrained line on many wallet and card-holder designs. For longer names, wallet interiors or narrow layouts, 3.5–5mm may leave better margins.

Is 8mm type suitable for luggage tags?

Yes. Eight-millimetre type is a strong choice for short names, initials and larger tags. Test the full name first, particularly when it contains several wide letters.

Is 10mm type too large for leatherwork?

It is too large for some jobs and exactly right for others. It works best for initials, short words, large labels and designs where the lettering should become a focal point.

Does larger type need a higher temperature?

Not automatically. Larger type increases the contact area, so even heating and pressure become important. Temperature still depends on the leather, foil, typeface, machine and contact time. Start with a tested setting and change one variable at a time.

Can small 3mm type be used on textured leather?

It can, but very fine strokes and serifs may lose definition on heavily textured surfaces. A smoother leather or a simpler, slightly heavier typeface will generally be more forgiving.

Is brass type size the same as a digital font size?

No. Physical type may be labelled by its visible capital height, while digital point size usually relates to the font’s em box. A 100 per cent printed cap-height test is more reliable than trying to convert directly from points to millimetres.

What is the best first brass type size?

For a mixed leathercraft workshop, 6mm is usually the most versatile starting point. Makers focused on smaller wallets may prefer 4–5mm, while studios producing tags and bold personalised work may get more use from 8mm.

References

Adobe (2025) ‘Vary font height in Illustrator’. Adobe Help Center. Accessed 19 July 2026.

CÍ OFFICIAL (2024) ‘About CÍ’. CÍ OFFICIAL. Accessed 19 July 2026.

CÍ OFFICIAL (2026a) ‘CÍ 10mm Brass Type Set for Hot Foil Stamping’. CÍ OFFICIAL. Accessed 19 July 2026.

CÍ OFFICIAL (2026b) ‘CÍ Deluxe Fine Brass Type Kit with Premium Walnut Box’. CÍ OFFICIAL. Accessed 19 July 2026.

CÍ OFFICIAL (2026c) ‘CÍ Deluxe 6mm Brass Hot Foil Stamping Type Set’. CÍ OFFICIAL. Accessed 19 July 2026.

CÍ OFFICIAL (2026d) ‘CÍ Deluxe 8mm Brass Hot Foil Stamping Type Set’. CÍ OFFICIAL. Accessed 19 July 2026.

CÍ OFFICIAL (2026e) ‘MAXITA Hot Foil Machine Movable Type Letter Set, 3mm, 6mm and 8mm’. CÍ OFFICIAL. Accessed 19 July 2026.

CÍ OFFICIAL (2026f) ‘Maxita Hot Foil Stamping and Embossing Machine EC-27’. CÍ OFFICIAL. Accessed 19 July 2026.

Reddit (2022) ‘Hot foil stamping question’. r/Leathercraft. Accessed 19 July 2026.

Reddit (2023) ‘Hot foil machine’. r/Leathercraft. Accessed 19 July 2026.

Reddit (2026) ‘Inking/Painting tiny stamps’. r/Leathercraft. Accessed 19 July 2026.