Shop Window Lettering: Which Film Goes on the Glass, and on Which Side

On many shopfronts, three generations of advertising are stuck on top of each other: opening hours from five years ago, next to them the remains of a promotion, above that a company logo that no longer matches the brand. Yet the window is the advertising space that works every day, even at seven on a Sunday morning.

With shop window lettering, the design comes last. Before that, you clarify which film suits the glass, whether it goes on the inside or outside, how much of the surface stays clear and which official rules apply at your location.

Which films are suitable for shop window lettering

There are several ways onto the glass. They differ in how much of the display you can still see afterwards.

Vinyl lettering for opening hours, company logos and wording

Vinyl lettering is plotted from through-coloured film, weeded with tweezers and squeegeed onto the glass with application tape. No background surface remains. Letters and logo stand free on the glass, and the window stays open in between. The cutting film we use most often is around 0.07 mm thick; its data sheet gives 3 to 8 years of vertical outdoor exposure depending on colour.

Printed film for designs, promotions and large-format window graphics

We digitally print white or clear self-adhesive film with your own design, from photos to solid colour areas. For the print film we run most often, 7 years of vertical outdoor exposure are stated for the unprinted material; printing and laminate change this value. On clear film, a design against a dark background needs a white layer beneath the colours.

Frosted and etched-glass effect as a privacy screen with design options

Glass decoration film blocks the view and lets the light in. The frosted glass decoration film we use most often is around 0.08 mm thick and rated at 7 years of vertical outdoor exposure; depending on the product, it is applied dry or wet. A logo or lettering can be cut out of a frosted film, so the brand stands out against the matte surface. Whether a film is designed for indoor or outdoor use is stated in the data sheet; ask about it before ordering.

Perforated film when the view from inside should remain

Perforated window film carries the design on the outside, while the view of the street remains from inside. That holds as long as it is brighter outside than inside; in the evening, with the lights on, the effect is reversed. For a common perforated window film, the data sheet states 4 years of vertical outdoor exposure, compared with 7 years unprinted for the solid print film next to it.

Inside or outside the glass: the decision before ordering

Outside, the film takes everything, from rain and sun to the cleaning service's brush. The data sheet values apply to vertical outdoor exposure in a normal Central European climate. Weatherproof does not mean unlimited there.

Inside, the same film is protected from weather and damage. The data sheets don't say that it therefore lasts longer; their values apply to the outside. For application behind the glass, there are versions printed in reverse; the design usually needs a white backing so that it is opaque from outside.

Dark solid areas on insulating or laminated glass are a special case. One film manufacturer warns in its data sheet that highly opaque or dark designs on glass exposed to the sun absorb more heat, which can cause the glass to crack. Check the glass construction, the area, any shading and your window maker's warranty terms beforehand. If in doubt, choose a lighter design, a partial area or application on the inside with white ink.

Supply the file the right way round and state “inside”; we do the mirroring. This applies to orders placed through our consultation; so it is best to order inside application there rather than via self-upload in the shop. In the free file check, we look at the technical side before printing: format, resolution, bleed, cut line, white layer and print orientation for inside or outside. We do not check content or spelling.

An installation date in January has a catch. The data sheets of the films we use usually give a minimum temperature of around 10 °C, and that means the temperature of the glass, not of the outside air. In practice you warm the glass first, switch to the inside, or move the appointment to milder days.

How much of the shop window should stay clear?

For the clear area, two viewing directions count. From outside, the eye still needs to find something that isn't film; from inside, the sales floor must not become dark.

Rules of thumb on the clear share of the surface and on letter height are going around. We deliberately don't pass any on here. They come from supplier articles, differ many times over, and we have not found an Austrian standard for them.

What remains is the test on site. Print the design at full size on paper, tape it into the window with masking tape and look at it from the pavement opposite, in daylight and with the lights on. In a pedestrian zone, people walk past more slowly and more closely than on a busy through road, and that changes the size you need more than any formula. And the glass reflects; what catches the eye in the morning can disappear into the reflection at midday.

Shop window lettering in Austria: which official rules apply

In Austria, building law and the protection of townscapes are matters for the federal provinces and municipalities, so the requirements differ by location.

Vienna. § 62a (1) no. 30 of the Vienna Building Code (Bauordnung für Wien) lists “individual illuminated and non-illuminated advertising signs or advertising symbols on buildings” with a circumscribed rectangular area of no more than 3 m² as exempt from permits, outside protection zones and areas under a building ban. In a protection zone, this exemption does not apply. The provision names advertising signs and advertising symbols on buildings; whether lettering film on your own window falls under it is not expressly regulated, so ask the municipality or the MA 19 before ordering. Add to that § 85 (4): shopfronts, shop and company signs, advertising symbols and illuminated advertising must not impair the local townscape. Shop lettering, illuminated signs and projecting signs are assessed by the MA 19, the City of Vienna's department for architecture and urban design.

Public land. § 1 (1) of the Vienna Public Land Use Levy Act 1966 (Gebrauchsabgabegesetz) is tied to public land and the airspace above it. The City of Vienna counts signs, lamps and awnings on or above a public traffic area among these; film on your own window is not listed there. The provision therefore becomes relevant for anything that projects over the pavement or the road and, according to WKO Wien, the Vienna Chamber of Commerce, also for the “cladding of the display surfaces of buildings or business premises”; for this, an application must be made to the MA 46 four weeks in advance. Where cladding begins is something the MA 46 can tell you.

Lower Austria. § 30 (2) no. 16 of the Lower Austria Spatial Planning Act 2014 (NÖ Raumordnungsgesetz) allows the local development plan (Bebauungsplan) to set the arrangement and design of advertising installations or to prohibit them. So the first place to look is the municipality's development plan.

Workplaces. Regardless of any advertising, § 6 (4) of the Austrian Workplace Regulation (Arbeitsstättenverordnung) requires transparent walls to be clearly marked, and § 7 (1) no. 6 requires transparent doors and gates to be marked at eye level. Under no. 7, transparent parts must also be made of safety material or protected against being pushed in; lettering film does not replace that. The regulation does not specify dimensions, colours or materials. Whether lettering meets the marking requirement is, if in doubt, assessed by the Labour Inspectorate (Arbeitsinspektorat); plan the marking separately from the advertising design.

This is guidance, not legal advice. Quotations from Austrian legal texts are our own unofficial translations. If in doubt, the competent authority decides.

Durability, cleaning and changing over to the next promotion

The service life depends on the film, the application side and the sun that falls on the glass. A south-facing window on the main street ages differently from one facing an inner courtyard. That's why the data sheets give a range.

Brief your cleaning service. No blade or glass scraper over the film, no pressure washer on the edges, no abrasive sponges.

For seasonal designs there is short-term removable film; for indoor use, the standard sticker from our shop is also available with a removable adhesive on request. Removable means easier to take off, not that nothing is ever left behind. So decide on the position beforehand.

Before the next promotion goes up, the old film has to come off; that is a separate job, which we take on if you wish. On glass, the film manufacturers' application guidelines advise against heat, because temperature differences can crack the pane; brittle film then often only comes off in pieces.

How it typically goes: two windows onto a side street, one stays a display

A shop with two windows onto a side street is planning a promotion. The design is to go on the inside, because in winter slush splashes up against the glass outside; the opening hours next to it go on the outside as vinyl lettering.

Before printing, the file check picks up two things. The file arrives mirrored, because someone was trying to think ahead; supplying it the right way round and stating “inside” is enough. And the design is set up dark on clear film with no white layer; from the street it would show through grey.

Something else isn't on any data sheet. The design was drawn for both windows; only the left one gets covered, and the right one stays a display window.

Why the clear area comes first

Good shop window lettering doesn't take space away from the display; it guides the eye towards it. Plan the clear area first and the design second, and you'll usually save yourself a second round of film. Our founder brought that order of work with him from more than 30 years in the trade when the company was set up in 2017.

That doesn't apply everywhere. Where nobody should be able to look in, blocking the view is the job. Then glass decoration film is the more honest choice than a full-coverage printed advert that only provides privacy as a side effect.

And a high-grade film is not automatically the right one. For a promotion that comes down again in February, the longest-lasting material is overdoing it. You'll find our vinyl work under Foil technology, and an example of a temporary promotion in Stickers you can't overlook.

Conclusion: three questions for the glass

Before every order, clarify the following:

• From which side will it be read? Inside or outside determines the film, whether the file is mirrored and the white layer.
• How long should it stay up? A six-week promotion and a five-year company presence call for different materials.
• How much of the window stays clear? A paper printout on the glass settles that.

We clarify in advance via Contact which film goes on which side.

Frequently asked questions

Does shop window lettering go on the inside or the outside?

Both are common. Outside, the service lives in the data sheets apply, which are given for outdoor exposure. Inside, the film is protected from weather and damage, but the design needs reverse printing and usually a white backing. For orders placed through our consultation, supply the file the right way round and state “inside”; we do the mirroring.

How long does shop window lettering last?

That depends on the film, the application side and the sun falling on the window. For cut vinyl lettering, data sheets give 3 to 8 years of vertical outdoor exposure depending on colour; for the print film we use most often, 7 years unprinted. Printing and laminate change that value, and so does the location. For promotions there is short-term removable film.

Do I need a permit for shop window lettering?

That depends on the location; building law in Austria is a matter for the federal provinces and municipalities. The Vienna Building Code names advertising signs and advertising symbols on buildings in § 62a (1) no. 30; whether film on your own window falls under this is not expressly regulated. Ask the municipality or the MA 19 before ordering. This is guidance, not legal advice.