Designing a bespoke neon sign: typeface, size, fixing and power supply
When you order a bespoke neon sign, four decisions absorb all the money and all the frustration: which typeface becomes tubing, how large the sign should be, what it is fixed to and how, and where it gets its power. The four are connected - the typeface sets the minimum size, the size sets the consumption.
What does 'neon sign' mean today?
In everyday speech, 'neon sign' covers two entirely different products. One is classic glass neon: hand-bent glass tube filled with noble gas, driven by a neon transformer at several thousand volts. The other - and the overwhelming majority of orders today - is LED neon flex: a densely populated row of SMD LEDs sealed in silicone or PVC, running on 12 or 24 volts DC, whose milky jacket blurs the point light of the individual LEDs so thoroughly that the profile looks like an even, unbroken line of light. From the outside the two are similar; their design rules, however, differ. This article is about LED neon flex throughout, because that is what can be manufactured for a bespoke sign at extra-low voltage, to a realistic lead time, and in a repairable way. A measurable comparison of the two technologies - power per metre, lifespan, safety, repairability - appears in our LED neon versus glass neon article, which also covers when it still makes sense to order real glass neon. That article is the home of the profiles' full technical data set - watts per linear metre, operating hours, cut-point spacing, minimum bending radius, ingress protection - and here we use only as much of it as the design decisions require.
The typeface: profile width is the real constraint. Why not every font becomes neon
LED neon profile is made to a given cross-section - the most common versions on the market are around 6x12, 8x16 and 10x20 mm. From this follows the most important design rule: the sign can contain no line thinner than the width of the profile. A high-contrast serif typeface with hairline strokes therefore cannot be made in neon the way it looks on screen - the thin and thick strokes merge into tubing of identical thickness, and the letterform loses its character. The typefaces that work for neon are those that already use an even stroke weight: script and handwriting fonts, geometric grotesques and rounded sans serifs. A practical rule of thumb: if the thinnest stroke of the font is less than half the thickest, the design needs redrawing. This test is worth doing with a ruler on artwork scaled to final size, because that is how you see what the measurement means in millimetres. The second geometric constraint is bendability: manufacturers' profile datasheets give the minimum bending radius as typically 2-5 centimetres depending on the profile, so sharp corners in letters and very tight inner curves - the loop of an ornate calligraphic flourish, for instance - come out rounded on the finished sign. These two values, the profile width and the minimum bending radius, should be copied from the datasheet of the chosen profile and written onto the visual.
Continuous line or separate runs: every cut costs money and adds a failure point
LED neon profile is bent from a continuous length, with two restrictions. One is that the strip can only be cut at the cut points marked by the manufacturer - often every 5 centimetres on 24 volt versions, and every 2.5-10 centimetres on others - so run lengths are not arbitrary. The other is that each profile can only be bent in its own direction: signs need the so-called side-bend version, which bends sideways in the plane of the light-emitting face, whereas the top-bend profile that curves up and down is made for curved cove lighting. Wherever the line breaks, you get a cut, a sealed tube end and a hidden linking wire. It follows that a continuous, single-stroke handwriting logo is made more cheaply and looks cleaner than a sign of the same width built from separate printed capitals: a five-letter word in separate letters means broadly 5-12 runs, while the same word in a handwriting font is often 1-3. Run count is not an aesthetic question: every link is a joint, and failures typically start at joints and unsealed tube ends, not at the LEDs. When you ask a manufacturer for a quotation, it is worth asking how many runs the design comes to - that number is a good indicator of the sign's real complexity.
Accented characters: the most delicate points in the artwork
A sign in a language that uses diacritics sets a design task that English-language samples never face. An acute, a grave or a circumflex is a short, separate piece of tubing; an umlaut is two dots; and a Hungarian double acute or a Scandinavian ring is two or more tiny marks that have to be bent alongside each other with a gap of a few millimetres. The problem is that the length of the shortest manufacturable element is set by the cut-point spacing and the sealing: if the strip can only be cut every 5 centimetres on 24 volt versions, or every 2.5-10 centimetres on others, no shorter accent piece can be made from it. The consequence is that lettering with diacritics effectively demands a larger minimum cap height than lettering without. There are two proven solutions: either choose a wording that is correct and legible without the accents, or draw the accents proportionally larger relative to the baseline, accepting that the typography will differ slightly from the file you saw on screen. This decision has to be made before the artwork is approved, not during manufacture.
Size: cap height comes from reading distance, not from the wall
The size of a sign is set not by how much free wall you have but by where it has to be read from. The sign trade has one widely used rule of thumb for this, which spread from American professional practice: 1 inch (2.54 cm) of cap height stays comfortably readable up to about 10 feet (roughly 3 metres). Converted to metric: every centimetre of cap height covers about 1.2 metres of reading distance - we use the same rule when sizing business signs and channel letters, so the two calculations are directly comparable. The same legibility tables put the just-decipherable limit at roughly three times the comfortable distance: that is an upper bound, not a target. The formula works both ways: divide the viewing distance in metres by 1.2 and you get the required cap height in centimetres. With LED neon there is also a technical lower limit: with an 8x16 mm profile, below a cap height of 10 cm the counters of the letters - the holes in a, e and o - become comparable with the thickness of the profile and close up into a blob of light. For an indoor decorative sign, therefore, 10-15 cm is a realistic starting point, for a shop window 15-25 cm, and for a facade company name above 25 cm.
Viewing distance and cap height: the design table
The table below works the previous section's rule of thumb through for common viewing distances, and sets alongside it what has to be considered specifically for LED neon. Every cap-height figure in the table comes from the same formula (viewing distance in metres divided by 1.2), so they come from a single, checkable ratio rather than from separate measurements. The right-hand column shows where neon differs from printed or cut lettering: at the smallest sizes the constraint is not visibility but the thickness of the profile, while at the largest the question becomes whether an illuminated channel letter would not be the more economical way to render the same company name.
Backing: contour-cut, rectangular or none at all
LED neon is flexible in itself, so it has to be held on something. There are three usual builds. A contour-cut clear acrylic backing follows the outline of the letters, so the sign appears to 'float' on the wall - this is the most refined and also the most labour-intensive solution, because the sheet has to be CNC-cut. A rectangular acrylic or painted backing is simpler, and works well if the sign is going into a panel-like frame anyway. A build with no backing, fixed directly to the wall, gives the cleanest look, but the fixing and hidden wiring are hardest here, and it also shows up any unevenness in the wall. The backing is typically made from 3-5 mm acrylic; on larger signs more than a metre wide, the thicker sheet is safer, because thin acrylic can warp over time under its own weight and temperature swings.
Fixing: wall, glass, ceiling - each has its own logic
On a wall, the backing is usually mounted on standoff screws, typically with 20-40 mm standoffs, so that shadow and air remain behind the sign and the cable has room. On shop-window glass, the usual solution is a clear acrylic backing with a bonded or suction-cup mount, or a wire suspended from the top edge - toughened glass cannot be drilled afterwards, since drilling after toughening shatters it. From a ceiling, steel-wire suspension comes into play, with the cable run alongside the wire and the sign's centre of gravity balanced, or it will hang crooked. Weight is rarely a problem, but it is worth calculating: a 5 mm acrylic backing alone is roughly 6 kg per square metre, on top of which come the profile and the fixings. Suitable plugs and screws carry that easily, but plasterboard needs special anchors, and on a larger sign it means locating the structure behind it.
Power: the most frequently underestimated part. Voltage, load, headroom
LED neon flex runs on 12 or 24 volts DC and typically draws 8-14 watts per linear metre; high-brightness and RGB profiles draw more, sometimes above 15 W/m. Our LED neon versus glass neon article, which is the home of the consumption data, gives the same range - always take the specific figure from the datasheet of the profile you have ordered rather than from the middle of the band. The calculation is therefore simple: measure the total length of the luminous line on the artwork in metres, multiply it by the power per metre from the profile datasheet, and add 20-30 per cent of headroom to the result. A six-linear-metre sign at 10 W/m draws 60 watts, for which a 75-100 watt power supply is the correct choice; a tightly sized supply runs hot constantly, and that shortens its life. The power supply does not disappear by itself: it needs a place behind the backing, in a suspended ceiling or in a cabinet, and it needs a mains connection point. Settle this at the site survey, not on the day of installation. The sizing logic is the same as for larger LED surfaces, only at a smaller scale - we have a separate article on sizing the power feed correctly.
Voltage drop: why it matters where the feed is
Over a long run, the resistance of the conductor track pulls the supply voltage down, and the end of the run glows more faintly than the start. The professional recommendation is that voltage drop should stay under 10 per cent of the nominal voltage, and the practical limit follows from that: roughly 5 metres on a 12 volt profile and roughly 10 metres on a 24 volt one is the run length above which you have to feed from both ends or from the middle. That is why we choose a 24 volt system for a long sign: at the same power, half the current flows, losses are lower, and the wiring can be done with thinner cable. If the sign consists of several separate words or lines, the correct solution is not to daisy-chain all the runs but to go out to each run in a star from a common distribution point. This difference shows up most clearly in the dark, between a sign that lights evenly and one that 'fades away at the end'.
Outdoors: ingress protection, condensation, where the power supply goes
A bespoke outdoor neon sign needs a profile rated at least IP65, with the tube ends factory sealed, and the cable entry routed with a downward drip loop so water does not run towards the connector. There are two good places for the power supply: either choose an outdoor-rated IP67 type, or - better - leave it indoors in a protected position and take only the extra-low-voltage cable outside. The common outdoor fault is not dramatic water ingress but condensation: inside a profile that is not hermetically sealed, the daily temperature swing causes moisture to condense and the sign mists up from within. That is why sealing the cut end is a critical point - outdoor failures typically start there. The problems familiar from larger illuminated signs - wind load, sizing the support structure - come up on a larger neon sign too, only with less weight behind them, because the structure is lighter.
Colour, brightness and dimming
LED neon is available in both single-colour (monochrome) and RGB versions. The single-colour version gives the cleaner, more saturated colour and shows up better in daylight; the RGB version changes colour and is programmable in exchange, but its whites and pastels are always weaker and it draws more power. On an indoor decorative sign it is almost always worth fitting a brightness control (a PWM dimmer): factory brightness can be uncomfortably strong at night in a dark room, and running it turned down also reduces consumption. Outdoors the problem is reversed: in daylight the sign looks faint, because neon - whether LED or glass - is made for an evening and dusk effect; if the content has to be legible in midday sun, that is a job for a high-brightness LED sign, not for neon. If the sign runs day and night, a time switch or a dusk switch improves both service life and the electricity bill.
Consents: the inside of a window and a facade are two different worlds
A neon sign placed on the inside of a shop window or within the retail space is generally not a public-space question. A sign mounted on a facade, as a projecting storefront sign or as a protruding structure, falls under the local authority's townscape rules. What size, brightness, animation or flashing is permitted is set locally, and it varies considerably from one municipality to the next: historic town centres are typically far more restrictive. In many places, installing such a sign involves a notification or consent procedure, and a structure reaching over public space usually needs a permit for use of public space as well. Which category a given sign falls into, and what is permitted, has to be read from the local rules - so the right order of work is to check them before the final artwork is drawn. We have a separate, detailed article on consents for outdoor advertising surfaces.
What each design decision costs
There is no price per square metre for a bespoke neon sign, because what is being made is a line, not a surface - so the price follows not from the overall dimensions of the sign but from the design decisions. The largest item is the total length of the luminous line in linear metres: this is set jointly by the length of the word and the linework of the typeface, and an ornate double-line logo needs more tubing than a wider, simpler sign. The second is the run count, that is, how many times the profile has to be cut, sealed and linked - this is where a single-stroke typeface pays for itself. The third is the construction of the backing: contour-cut acrylic is considerably more machine time than a simple rectangle. The fourth is the ingress protection: an outdoor IP65 profile and the matching power supply cost more than the indoor equivalents. The fifth is accessories and installation: dimmer, RGB controller, remote, and whether the fitting is to a wall, to glass or at height. That is why two signs of identical size on paper can differ several times over in price: the difference lies in the run count, the backing and the ingress protection, not in the size. If a quotation shows a single sum, ask for it itemised - that is how you see which design decision is taking the money.
Lifespan, repairability, maintenance
The realistic design lifespan of LED neon flex is 30,000-50,000 operating hours to L70, that is, for as long as brightness stays above 70 per cent of the initial value; what puts a given installation at the bottom or the top of that band, and why it cannot be compared with the L50 hour figures familiar from LED walls, is worked through in our LED neon versus glass neon article. From a design point of view, what matters more is that a sign does not typically fail at the end of its rated life. The LEDs are rarely the first thing to tire: it is far more common for the power supply to age, or for the profile to take mechanical damage - and both are replaceable parts. A damaged run can be replaced without dismantling the adjacent runs, provided the assembly was built with connectors rather than permanently soldered; this is worth stipulating at the quotation stage. There are two maintenance tasks. One is dusting: silicone profile attracts dust, and the layer deposited over the years noticeably reduces brightness - a soft, dry cloth is enough. The other is an annual check of the connections outdoors, because the joints are the first thing to fail.
What to hand the manufacturer: the artwork checklist
Manufacture starts from a vector file. A usable design needs the lettering converted to curves (the font must not remain live text, because a different typeface will be on the manufacturer's machine), the final width and height stated in millimetres, and a clear indication of which lines light up and which are purely graphic elements. Beyond that, four pieces of information decide everything: whether the location is indoors or outdoors, what the viewing distance is, where the nearest mains connection point is, and what material the surface is that we are fixing to (brick, plasterboard, glass, metal). If those four are available at the site survey, the designer can return a manufacturable version on the first pass, and the start of the project is not eaten up by sending artwork back and forth.
Expert tip
Do two measurements before approval; both are free. The first is the stroke test: scale the artwork up to final size and measure the thinnest stroke with a ruler. If it is smaller than the width of the chosen profile - typically 6-20 mm - then the finished sign will show thicker letters than the visual, and it is the typeface that has to change, not the manufacturer. The second is the distance test: divide the viewing distance in metres by 1.2, and the result in centimetres is the required cap height; print the sign at that size, taped together from several sheets, stick it up in its intended position, and look at it from where the customer will actually see it - from the pavement, from behind the counter, from the doorway. With accented lettering, look separately at the marks above the letters: if they merge on paper, they will merge in neon too.
Common mistakes
1. Choosing a high-contrast serif typeface with hairline strokes: you cannot go below the 6-20 mm cross-section of LED neon profile, so thin and thick strokes swell to the same thickness and the letterform loses its character. The same geometric constraint applies to curves: manufacturers' profile datasheets give the minimum bending radius as typically 2-5 centimetres depending on profile, the profile will not take a tighter curve, and sharp corners and tight inner loops come out rounded on the finished sign. 2. Choosing the size from the free wall area rather than the viewing distance. The rule of thumb is that every centimetre of cap height covers about 1.2 metres of reading distance - work back from that, not from the size of the wall. 3. Accented characters force a minimum cap height that many people notice only at manufacture. Lettering with diacritics has to start from a larger base size. 4. Forgetting where the power supply goes. It has to fit behind the backing, in a suspended ceiling or in a cabinet, and it needs a mains connection - settle this at the site survey, not on installation day. 5. A tightly sized power supply. You need 20-30 per cent of headroom above the calculated load, otherwise the supply runs hot constantly and will be the first component to fail. 6. Feeding a long sign from a single point. Above roughly 5 metres at 12 volts and 10 metres at 24, the end of the run is visibly fainter - feed it from both ends or from a star distribution. 7. Using an indoor, low-rated profile outdoors, or leaving the cut tube end unsealed. Outdoors you need at least IP65, a sealed tube end and a drip loop at the cable entry, or condensation will mist the sign up from the inside. 8. Designing a facade sign without checking the local townscape rules first: a restriction on permitted size, brightness or flashing can force the whole artwork to be redrawn afterwards.
| Where it has to be read from | Calculated cap height (viewing distance / 1.2) | Typical placement | What to allow for specifically with LED neon |
|---|---|---|---|
| 3 m - from behind the counter, close up | approx. 2.5 cm | indoor decorative sign, counter sign | not manufacturable at this size: the thickness of the profile puts the practical floor around 10 cm |
| 6 m - standing in front of the window | approx. 5 cm | window sign, in-store logo | enough for legibility but not for manufacture - start from 10-15 cm |
| 12 m - from the opposite pavement, narrow street | approx. 10 cm | sign above the shopfront | this is the practical minimum for LED neon; accented lettering needs one size larger |
| 20 m - arriving at the shop, from the car park | approx. 17 cm | shopfront, lower band of the facade | this is the range where LED neon works best |
| 30 m - from the opposite pavement, wide street | approx. 25 cm | company name on the facade | the size of the backing and the run count become the main cost driver, not the cap height |
| 50 m - from the road, from a moving car | approx. 42 cm | large facade, prominent company name | at this size, illuminated channel letters are often the more economical solution |
A few questions and you get the recommended pixel pitch, the size and an indicative price.
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