For most businesses, a window is more than a way of letting light in. It is the first thing a customer sees,
a place to explain what you do, and one of the cheapest advertising spaces you own.
Whether it is a simple logo on a shop door, opening hours across a high street window, or a full colour
promotion covering the whole frontage, window vinyl helps a business look professional and gets noticed
from the pavement.
From retailers and cafés to offices, gyms, salons and estate agents, window graphics are one of the most
effective ways to turn a passing glance into a visit.
To see some of our work, visit our window graphics page.
What Does Vinyl Inside or Outside the Glass Mean?
Window vinyl can be applied to either face of a pane of glass. The outside face is the one you can touch
from the street. The inside face is the one you can touch from within the shop.
The same graphic, the same material and the same installer can produce a very different result
depending on which face it goes on. It changes how long the vinyl lasts, how strong the colour looks, and
whether the lettering reads the right way round.
It also decides whether the job is possible at all. Some windows only give you access to one face, and
some types of glass should not be covered on certain surfaces.
This guide explains both options so you can choose the right one before the artwork is approved.
First Surface and Second Surface
The industry describes the two options as first surface and second surface, and those terms often appear
on quotes.
First surface means the vinyl is applied to the outer face of the glass, so the film is exposed to the street.
Second surface means the vinyl is applied to the inner face, so the glass sits between the film and the
person looking at it.
Once you know which is which, the rest of the decision becomes straightforward.
Vinyl on the Outside Face
Outside application is the simplest option. The artwork is cut or printed the correct way round, applied to
the outer surface, and viewed directly.
This gives the strongest colour. There is nothing between the ink and the eye, so printed graphics stay
vivid and sharp, even on a busy high street where the window has to compete with reflections and
passing traffic.
It is also the only practical choice when there is no access to the inside of the window, such as a glazed
door that opens outward or a display window with a solid panel behind it.
The trade-off is exposure. Sun, rain, frost, road grime and window cleaning all act on the same surface
that carries your artwork, so outside graphics need exterior-grade cast vinyl and sealed edges to last.
Vinyl on the Inside Face
Inside application puts the film behind the glass. The glass protects the artwork and, unavoidably,
changes how it looks.
This is the longer-life option. Film that never sees weather or cleaning chemicals lasts far longer, and the
glass protects the printed surface from scratches and graffiti. It is why corporate manifestations, door
safety markings and privacy graphics are almost always fitted internally.
The catch is optical. Glass reflects light and carries a slight tint, so colours viewed through it lose a little
depth, and reflections of the street layer over the artwork rather than sitting beside it.
There is also a production step involved, which is covered below.
Why Colour Changes Behind Glass
A graphic applied internally is being viewed through a pane of glass, and that pane is never
perfectly clear.
Even good quality glass reflects a percentage of the light that hits it and carries a faint green tint, which
becomes more noticeable in thicker or laminated sections.
On a bright day the effect is obvious. A printed colour panel that looks strong and saturated on the
outside face can look washed or dusty on the inside face, because the sky and the buildings opposite are
reflected across it.
This does not mean internal graphics look poor. It means the design should account for it, with stronger
colours and simpler shapes than you might use on an external window.
The Reversal Problem
This is the most common mistake we see when a client supplies their own artwork for an internal window.
A graphic applied to the inside of the glass is read through the glass, which means it must be mirrored.
Cut vinyl lettering has to be cut back to front, and printed graphics have to be printed in reverse.
If that step is missed, the vinyl is applied perfectly and the street still reads it backwards.
Many print materials are only printable on one face, so the material is often chosen because of the
reversal rather than for its finish. Frosted, white and metallic films also look different depending on which
side you view them from.
The lesson is simple. Tell your signage company which face you intend to use before the artwork is
finalised, not after.
Frosted Film and Privacy Graphics
Not every window graphic is there to advertise. Frosted film is used to create privacy while still letting
light through, and it is one of the most common internal applications we produce.
It works well on office partitions, meeting rooms, clinic and salon windows, and the lower half of shop
windows where stock or a back office should not be on display.
Frosted film can be cut into patterns, logos, manifestations or simple bands, and can be combined with
cut vinyl lettering for a complete internal scheme.
Because the film sits behind the glass, it stays clean and is protected from contact, which is why privacy
work is almost always specified as a second surface application.
To see our frosting options, visit our privacy frosting page.
Why the Glass Itself Matters
Not all glass behaves the same, and some of it limits your options.
Single glazing is the simplest case. Either face is available, and internal application is usually the better
long-term choice at eye level.
Sealed double or triple glazed units only allow access to the room-side face of the inner pane, or the
outer face if the graphic is external. The sealed cavity cannot be reached once the unit is made, and
covering large areas can affect how the unit handles heat.
Some units carry a soft-coat low-emissivity or solar control coating, which can be damaged by adhesive
and by removal. That specification needs checking with the glazing manufacturer before anything
is applied.
Laminated and toughened glass is generally fine, but fire-rated doors and escape routes can carry an
intumescent layer that must not be covered. Curved and textured glass bring their own problems: vinyl
will not conform to compound curves, and textured glass shows adhesive as a visible pattern.
If you are not sure what is in your window, send us a photo and the building details. It takes minutes to
check and prevents an expensive mistake.
Choosing the Right Option for Your Business
The right choice depends on what the window has to do.
If it has to shout, such as a promotion, a launch or a full colour seasonal takeover, the outside face gives
you the impact and you accept that it is a shorter-life graphic.
If it has to last, sit at eye level, provide privacy or mark a door, the inside face gives you durability and
protection, and you accept the mirror-printing step and the slight softening of colour.
Access matters too. External work above ground floor may need a tower or MEWP, which affects cost,
while internal work often needs nothing more than a stepladder and out-of-hours access.
For maximum colour impact on a shopfront, see our full colour graphics page. For single-colour lettering
and simple marks, cut vinyl graphics are usually the better answer.
Designed, Produced and Installed Properly
Window graphics need to be designed for the glass they are going on, including the frame, the mullions,
the door gaps and the sightlines from the street.
A design that looks good flat on a screen still has to work once it is on the pane, read from the pavement
and viewed alongside reflections.
Clean glass, correct surface preparation and proper squeegee technique decide the finish.
Contamination under the film shows up permanently, and edges that are not sealed will lift.
At Yellow Signs, we produce and install window graphics across London and the South East, from simple
cut vinyl lettering to full colour printed window schemes.
Get Your Windows Branded
Window graphics are one of the cheapest ways to promote a business every day. Your window is seen
by everyone who walks past, and the right graphic makes the most of that.
From a single line of cut vinyl to a fully printed shopfront, the right choice between inside and outside
application can make the difference between a graphic that lasts years and one that needs replacing
within two.
If you are planning window graphics and are not sure which face to use, our team can advise on artwork,
materials, production and installation.
To request a quote or discuss your next window graphics project, contact our team.