Have you ever wondered why so many digital signs are placed, hung or duct-taped to such seemingly terrible places? At airports, hotels and retail stores I often find myself wondering "what on earth were they thinking when they put that there?" Upon completing some research on the subject, I realize why this probably happens: what looks good to one person doesn't necessarily look good to all -- and I don't just mean aesthetically. The fact is, where a screen is placed and the angle at which it addresses its viewing audience can be almost as important as the content playing on screen, and the optimal angle and placement is different for virtually everyone. This makes things tough for store planners and venue owners preparing for a digital signage deployment. So while we've given plenty of attention to making great content, today I want to focus on the relatively unknown and still under-appreciated art of screen placement.

The Angle of the Dangle

There are two parts to figuring out the expected viewing angle. Well, three, really. First is the angle at which the screens actually hang. Second is the expected angle of incidence of the viewer (in other words, the angle a viewer's head might be expected to be at while approaching your screens). And third, in some cases, is the "correction angle" that you use to compensate for any obstacles that might come up between your viewers and your screens. Consequently, I can't give you general wisdom like "hang the screens at a 17 degree angle from the floor". Without knowing the size and shape of the store, its layout, the average height of a viewer, etc., there's no way to make that recommendation. However, we have determined a few key facts that influence how one might go about placing screens in a venue.

For example, a person with normal 20/20 vision has pretty decent visual acuity for about six or seven meters (roughly 20-23 feet). They can read text a few inches tall from that distance without too much trouble (you'll see why this is important later on). A few years ago, Walmart Mexico did some research and found that it takes a typical shopper somewhere between 5 and 7 seconds to cover that distance. This means that if you put a screen smack-dab in front of somebody at precisely their own eye level, you'd have at most 5-7 seconds to get your message across, assuming they were paying attention to your screen the whole time (which, of course, they won't be). By fiddling with screen placement -- both the height of the screen from the floor and the angle at which it points relative to the floor -- you will directly impact how much time a typical viewer has for taking in your message.


(Thanks to blog contributor Axel Vera for unknowingly supplying me with a bunch of graphics and icons to slice and dice into these charts.)

Wait, the amount of time changes?

That's right. It's a little counter-intuitive until you think about it: if I put a sign right in front of you about 20 feet away, and it's at exactly your eye level, then assuming you have normal vision, you will be able to see that sign for every moment that you approach it. If I pitch the sign a few degrees up or down, that's going to make it a little harder to see while you're far away -- up close it should be fine, but let's say you can now only see it clearly from 18 feet away instead of 20. I've just decreased the amount of time I have to message you by 10%. Since I can't possibly know your exact height or adjust my sign's position relative to each new viewer that comes into range, all I can do is pick a representative height and angle and hope that it works well enough that a big percentage of my viewers will be able to see it.



What's more, just because a screen is in front of a viewer doesn't mean that it falls within his field of attention, which is considerably narrower than his field of vision. The field of attention only constitutes about 20-25 degrees of your field of vision. This means that you'll actually have a lot less than 5-7 seconds to connect with a viewer (and get him to turn his head towards the screen). If your screen is a mere 5 feet away, it'll have to be within about 2 feet of eye level to be in the field of attention. At 10-11 feet away, it needs to be within 4 feet of eye level. At the "full" 20-22 feet away (the maximum we can count on a person of normal vision being able to see clearly, assuming normal-sized text, etc.), it would need to be within about 8.5 feet of eye-level. If we assume the average shopper at a retail store is 5 feet 6 inches or so, then a screen should never be more than 14 feet off the ground (8.5 + 5.5 = 14). Having a screen placed so high up does mean that more people will probably "see" it (though not necessarily be able to take in its message). But it also means that the average viewer will have to be a bit closer before they can read it clearly (since the distance from the eye to screen is the red hypotenuse line, not the black linear distance line), and that it will be in the average viewer's field of attention for a shorter period of time than if it was placed closer to eye-level. In a shelf-mount or endcap scenario, again if your typical viewer is 5'6" then your screens should be placed from 3'6" to 7'6" for maximum attention time, again with the best bet being at just around eye-level.

How do we increase viewing time?

Well, the obvious answer is to make such amazingly beautiful and compelling content that it simply can't be ignored and draws viewers in like moths to a flame. Or you could use some gratuitous nud ity, but that's likely to get you fired and sued in a hurry. Really, the best practical answer is to make sure your messages are easily understandable from a distance so that you give approaching viewers more time to see the message and act upon it. We've given you all sorts of tips on how to make great digital signage content in the past, but I'll add just a little more data to that conversation today. While visual images do most of the communicating on digital signage systems, text still does most of the selling, so that seems like an obvious place to try some optimizations. If we go back to the premise that an average viewer should be able to read your screen from about 6-7 meters (20-23 feet) away, that means the text on screen needs to be about 2 inches tall. That translates to about 50-60 pixels on a typical 40" 1360x768 screen. If that same size of screen is running at 1080p resolution (1920x1080), the text would need to be about 115-130 pixels tall. Speaking of which...



I get asked so many questions about whether to use high-def (1080p) screens or not. This chart is my new answer. The bottom line is that either your screens have to be whompin' big, or your viewers need to be really close to realize any benefit from moving from 720p to 1080p. So for most applications today, there's probably no reason to go with the added cost, complexity and bandwidth/server/player needs of 1080p content. If you're in an environment where people will be really close to your large screens, then sure, it might be worth it. But if you're using 19" screens on an endcap or 40" displays atop high shelves, there's really no point.

Ok, so now you can whip out your planograms and a protractor and start figuring out where put your screens, right? Well, almost. You might want to wait a little while, because next time I'm going to talk about some in-store research that sheds a bit of light on where in a store you should place your messages for optimal impact. Whether you're planning a new deployment or a retrofit of some existing screens, we'll be looking at why viewing angles are only one part of the equation.

I once saw a 42" plasma mounted directly behind a two-foot-thick concrete pillar. What's the worst-placed screen that you've ever seen?

Comments   

0 # Robin 2009-04-02 17:12
Bill - this is my local IGA store in Toronto. What do you reckon? They seem to meet your criteria but I have to say I have never seen anyone take one look at that screen. http://picasaweb.google.com/shopperwatch/DropBox?authkey=Gv1sRgCJ_zkYu-19i-kgE&pli=1&gsessionid=cT-orMcTOnMhto1YR5tWmw#5320142134875690034 Would love to hear what you think.
0 # Bill Gerba 2009-04-03 04:46
Hmm, let's have a look... Well, traffic certainly doesn't appear to be the problem :) And given how tight that space looks, I don't think it could be placed lower or off to the side. Of course, just because you **can** put a screen there doesn't mean that you **should**. And just because somebody has followed (roughly) the guidelines above certainly doesn't mean that their screens will be looked at -- consider them more of a set of "minimum requirements" than anything else. In your example the screen: 1. blends into the fluorescent fixtures 2. is facing (at best) only 50% of the potential aisle traffic 3. isn't at all integrated into the store's layout Further, power/outer aisle screens are notoriously difficult to make content for. These are glance media at their utmost - I'd guess you have no more than a split second to attract the eye. The screen's going to be tough to move, but I bet you could get better results with some optimized content of some sort (sounds easy to say, can be fiendishly hard to make, test, remake, retest, etc.).
+1 # Lisa 2009-11-13 04:32
Hi Bill Interesting article. What do you think would be the best use of digital signage within a small store such as a convenience store, supported by advertising? From an advertiser's point of view, is option 1 or 2 better in your view? Option 1: A number of smaller (13"-15") screens at shelf-mount or endcap at just around eye level Option 2: One or two 40" - 46" screens at the back of the wall hanging off the ceiling? Thanks.
0 # DuWayne 2009-11-16 18:00
Hi Bill I have the same question as Lisa. What do you think would be the best use of digital signage within a small store such as a convenience store, supported by advertising? From an advertiser's point of view, is option 1 or 2 better in your view? Option 1: A number of smaller (13"-15") screens at shelf-mount or endcap at just around eye level Option 2: One or two 40" - 46" screens at the back of the wall hanging off the ceiling? Thanks.
0 # Bill Gerba 2009-11-17 16:30
Lisa and DuWayne, I just wrote an article based on your question. It's called "[[http://www.wirespring.com/dynamic_digital_signa ge_and_interactive_kiosks_journal/articles/The_DOO H_Advertising_Paradox__Better_Spots_Are_Harder_to_ Sell-751.html|The DOOH Advertising Paradox: Better Spots Are Harder to Sell]]" I hope you find it helpful. Best, Bill
0 # Freddy Murstad 2009-12-19 16:23
Hi Bill. In your post you ended the post by saying: Ok, so now you can whip out your planograms and a protractor and start figuring out where put your screens, right? Well, almost. You might want to wait a little while, because next time I'm going to talk about some in-store research that sheds a bit of light on where in a store you should place your messages for optimal impact. Whether you're planning a new deployment or a retrofit of some existing screens, we'll be looking at why viewing angles are only one part of the equation. I am looking for this specific article. It may be that it has been posted later, but I rushed trough som eof them and couldn't find it.
+1 # Bill Gerba 2009-12-24 20:07
Hi Freddy, I only just got around to writing that article last week. [[http://www.wirespring.com/dynamic_digital_signag e_and_interactive_kiosks_journal/articles/Digital_ Signage_Screen_Placement__Targeting_the_Attention_ Zone-754.html|It's called Digital Signage Screen Placement: Targeting the Attention Zone]]. Hope you find it helpful! Best, Bill
-2 # Boss 2011-06-06 23:35
This is very interesting to read signs on screens. but if a sign is to be placed twenty feet from where people will be expected to read it. How large (in inches) should the smallest characters be on the sign and at what visual visual angle?
+1 # Bill Gerba 2011-06-07 18:57
Hi Boss, All else equal, an average viewer with average 20/20 vision can theoretically see details as small as 1/16 of an inch at 20 feet. However, given distractions, poor viewing angles, etc., that's an impractical number. Instead, we recommend a minimum font size of one inch high to be sure it can be seen clearly from 25 feet away. There's more detail in our article on [[http://www.wirespring.com/dynamic_digital_signag e_and_interactive_kiosks_journal/articles/Making_g reat_digital_signage_content__Sorting_out_font_fac es__sizes_and_styles-383.html|Sorting out font faces, sizes and styles]]
0 # Diallo Dixon 2016-05-23 15:38
Just came across this website today, great blog and interesting post here! I wanted to know, what about a 10 inch screen right by the cash register? How effective do you think this will be? I'm guessing that only those purchasing an item will see it but it will have 100% viewability of those buying an item.
+1 # Bill 2016-05-25 18:14
This really depends on what you're doing with that screen. Since the viewer is already making their purchase, you're not going to affect that trip's performance, so now you're talking about influencing out-of-venue behavior or hoping to modify the next trip's behavior -- both are extremely difficult, and definitely not the best use of an in-store digital signage application
0 # Diallo Dixon 2016-05-25 20:52
Ok let me explain further. It is a combination of Point-of-sale advertising and reciprocal marketing e.g. A women's shoe store at the point of sale will have a 10 inch digital screen advertising a hair salon. That hair salon at their point of sale will have a screen advertising that women's shoe store. Both share the same type of customer (i.e. mainly women) and are advertising complementary products/services. Concept can be expanded to anywhere women normally spend their money (clothing boutiques/spas/florists/wedding stores/etc) and so on for other types of customers (men, kids, teens, etc) and industries (beauty, automotive, medical, etc). It is geared towards micro/small businesses with smaller budgets (hence the smaller screen size). What I dont know and am hoping you can tell me is if there is any big negative to advertising on a small 10 inch screen? Remember it will be right at the point of sale.
-2 # Bill 2016-05-26 04:07
Hyperlocal ad networks are nothing new, but they require a lot of legwork to maintain profitable ad sales levels. I don't see small screens at the point of sale as being a benefit. Maybe if they were combined with some way of delivering time-sensitive promotions (mobile coupons or something like that), but those are often viewed as just another cost center by small businesses. We have research in other blog articles showing the effect of screen size on message recognition and retention -- bigger *is* better when it comes to digital signage.

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