An assumed scenario, constructed to show the decision. It describes no named customer and reports no measured result.
A shop window starts as a bright idea and turns into a complaint about four months later. The screen is fine. The problem is that the shop opposite has a white wall, and at three in the afternoon the sun bounces off it, through the glass, and lands on the display. It was not foreseen, because nobody stood outside at three in the afternoon before ordering.
A window project usually starts going wrong before the order is placed, in a survey that was skipped. This guide is what to look at, what to write down, and what to agree with your supplier before you place the order.
Stand outside first
Before you think about a screen, stand on the pavement where your customers walk past, at three different times of day, and look at the window.
Morning, early afternoon and late afternoon, on a trading day. Take a photograph from the same spot each time, so you can compare them later. Then walk inside and look out through the same glass from where the screen would sit.
You are looking for three things.
Where the light comes from. A window facing east gets hard light in the morning. A window facing west gets it in the late afternoon, and where the shop is busy at that hour the two problems arrive together. The same screen in the same shop can be perfectly readable at eleven and unreadable at four.
What reflects. Tinted glass, a glossy shop floor, a bright wall opposite, a polished counter, a streetlight at night — all of these put something between your customer and the screen. A reflection puts something in front of your message, and a bright panel does not remove it. It is also the one thing a specification sheet cannot tell you, because the reflection belongs to your street rather than to the screen.
Who is actually looking. Somebody walking past at normal speed gets a few seconds. If the message needs more than that, the position is wrong or the message is too long.
Write it down, because you will need it later
Keep a short record of the survey. It is not paperwork for its own sake: it is the document you will use to reject a screen that does not perform, and the document a supplier needs to recommend something honest.
| What to record | What goes in it |
|---|---|
| Which way the window faces | Compass direction, and the times of day when direct sun reaches the glass |
| The glass itself | Tint, coating or film, and whether it is double glazed |
| What reflects | The shop floor, the wall or building opposite, counters, streetlights |
| The light through the day | Your photographs, with the time each one was taken |
| The message | The offer, and the smallest text that has to be readable from outside |
| The screen position | Where it will stand, how far from the glass, and how the cables get there |
| Cleaning and access | How somebody reaches the inside of the glass and the back of the screen |
The last row is the one that gets left out and then regretted. A window display nobody can clean stops looking like a display well before the campaign ends, and the person who has to move it to reach the glass will tell you about it at the worst possible moment.
What a brightness figure does and does not tell you
Suppliers quote a brightness figure, usually in nits. It is a real and useful number, and it is also the most misread number in this business, because it describes the panel and your customer sees the whole window.
Ask four things about any brightness figure you are given: which model it is for, where on the panel it was measured, at what setting, and under what conditions. A figure without those four answers cannot be compared with anything, including another figure from the same supplier.
Then ask the more useful question. Can the display be put behind your actual glass, running your actual content, at the hour you identified as the worst one?
If that can happen before you order, you will know more from ten minutes of looking than from any specification sheet. If it cannot happen before you order, write down what is still unknown and agree how you will check it afterwards. An open question on paper is a professional position. "It should be fine, it's a high brightness panel" is not.
Make the message readable from the pavement
Content is one of the causes worth ruling out first, before the screen is blamed.
One idea. A person walking past will not read a second sentence. Price, offer, and the one condition that matters — that is usually the whole message. If the requirement is a floor plan rather than a promotion, the wayfinding planning guide covers lists and reach height.
Design it at the size people see it. A layout that looks fine on a laptop has not been tested. Look at it at the real size, from the real distance, with the real content in the playlist position where somebody first sees it.
Do not use sound. On a street, through glass, audio is not a channel. If the message needs sound, it needs rewriting.
When it does not work, change one thing at a time and keep a note of which change fixed it: less text, a simpler layout, a different position, or a different screen. Changing three things at once means you learn nothing, and the next shop repeats the mistake.
One warning about photographs. A camera adjusts its exposure, so a photo of a screen can look far better or far worse than the real thing. Use the photo as a record of what you tested, and judge readability with your own eyes.
Heat, air and access
A display sitting behind glass in the sun is in a warm space with limited airflow, and that affects how long it lasts. Three things to settle with your installer before ordering.
The gap between the screen and the glass. Some air movement behind the display is usually better than none. How much, and how it moves, depends on the screen and the window, so confirm it against the documentation for the specific model.
The mount. How the screen is fixed, what it is fixed to, and whether that can carry the weight. This is an installer's assessment, not a specification sheet question.
How somebody reaches it. Cleaning the glass, cleaning the screen, changing a cable. If reaching any of those means dismantling the window, say so now rather than in the first month.
Two assumptions are worth naming, because both cost money. A screen behind glass is not an outdoor screen — it is indoors, with sunlight and heat on it. And a screen is not the same as another screen in the same brochure: clearances, temperature limits and maintenance requirements belong to the model you are actually buying.
Agree how you will accept it before you order
The cheapest protection in a window project is an acceptance test written down before you buy. Five things belong in it.
- The hour you identified as the worst one.
- Your real content, not a test pattern.
- The real viewing position — the pavement, the doorway, the spot where customers slow down — with photographs from fixed points.
- A full run: switch on, change the content, interrupt the power, and check that it comes back correctly.
- The record: what was measured, which content was used, and who signed it off.
Add one line to the contract: the display is checked through the actual glass, on site, before final acceptance. A supplier who objects to that line has told you something useful.
Work out who keeps it current
A window display goes stale faster than any other screen in a shop, because the offer changes weekly. Decide before installation who checks that the price on the window matches the price at the till, and how they will check it — from outside, where the customer stands. Agree what the screen shows if the content feed fails, and make sure the answer is not a black rectangle on the busiest street in town.
For campaign scheduling, see the holiday retail signage checklist. For how the window position fits the rest of the store, see the retail placement guide.
What this guide does not cover
It gives no recommended brightness figure, because no single figure suits every orientation, coating and duty cycle. Glazing, structure and electrical work need qualified trades for the specific building, and price and warranty terms are confirmed per order.
Send the photographs, get a view on the window
Send us the photographs from outside and inside, the worst hour you identified, your content at its smallest readable size, the intended screen position and how you plan to mount it. We will come back with the options that suit that window and what each one needs for installation, cleaning and access.
Compiled September 29, 2026. The method is the author's; the external sources are listed above, and the opening scenario is constructed rather than reported.
