20/20 Vision - And How It Relates - A little Science - By the Numbers
Do you have 20/20 vision? I do (with my glasses on). What does that mean? Basically you can read the 20 line at 20 feet. Well, not really, it means you can "make out individual letters" it isn't really legible! Can you imagine trying to read a book from 20 feet away if all the letters were 20/20 size. Ridiculous!
A typical Snellen eye chart
OK, check this out: The characters on the 20/40 line are twice as tall and twice as wide (4 times the area) of those on the 20/20 line. That way, if you move back from 20 feet to 40 feet, the "20/40" line type will appear the same size as the 20/20 line type did at 20 feet. According to experts, even larger type on the 20/40 line - that one isn't quite large enough - but the ones on a theoretical 20/60 line would be legible for reading. Got it? Good!
Now, before you call me on it (re content below), the Snellen chart doesn't have a 20/60 line, it goes 20/20, 20/25, 20/40, 20/50, then to 20/70, 20/100 and so on...that's why I dropped in that word theoretical.
The 4/6/8 rule as it relates to the Snellen chart - the eye chart, with the 20/20, etc.
Those experts: For good legibility it's the ANSI standards folks that say that the recommended (minimum) type size for legibility would be the equivalent of that 20/60 line, that is, roughly 3x the height, 9x the area of a 20/20 character.
So now it's time to revisit the typical desktop user's ability to read their screen, with this in mind:
Reading the 20/60 line on the eye chart is the equivalent of reading 11 point type on that 21" monitor from 28 inches. In both cases, the type is large enough to be fully legible.
Next: That's from 28 inches. For the same equivalent ability to read that 11 point type, if we wanted our monitor at 56 inches away instead of 28, we would need to go from a 21 inch display to a 42 inch display. On the 42 inch display, at that distance, the 11 point type appears the same size as before, aka legible.
But in a conference room, huddle space or other working area, not everyone is going to be sitting with their eyes within 4 feet 8 inches (56 inches) of the display. Not even close.
Let's assume that everyone is within 9 feet 4 inches of the display. Since that is twice as far again, we need to double the size of our display to an 84 inch diagonal. At 12 feet we will need about a 100" display...
Yet most conference type rooms have five, or six foot diagonal screens or 6 foot wide ones, and if using plasmas or LCDTVS typically 60 inches or less.
The point is, with displays that small, it makes for one really tough read (of the typical 10-12 point type used on most documents).
Classrooms are no different than conference rooms. It a typical K-12 classroom some students are going to be at least 15 feet back from the front of the room. Even with the 4/6/8 rule, we're talking 100" screen size, but even larger for the more realistic Equivalent Visibility rule.
Even by 4/6/8, a K-8 classroom should be considering a 100" diagonal display size, whether monitor or projector!
These two charts are from the Display Size Matters. This first one describes what is needed in a typical small K-8 classroom!
The full white paper discusses the alternative rule they call Equivalent Visibility, which is basically what I've just described.
The rule is based on this simple concept:
If 11 point type works for everyone on that 21 inch, from 28 inches away, then why not make that the standard: The ability to have that level of legibility for the entire group in a collaboration?
Makes sense to me. Its time to "fix" this problem. As a business owner and a presenter, I know what we're talking about here. I can't even count how many times while speaking to my employees, at monthly meetings, where I've said - "I know you can't read the smaller type on the screen - what it says is..." or something like that. Haven't we all?
Equivalent Visibility is easy to understand, because it makes sense.
The "problem" is that in collaboration meetings, too often, people are too far back from the display to be able to read a lot of the information being discussed. Worse, "they" say, bosses who aren't running the meetings tend to sit in the back - where they are least likely to be able to read the content. Ouch!
How Equivalent Visibility works is this simple:
I repeat again, for emphasis: If you can read 11 point type on a 21 inch display from 28 inches, then for any sized room and seating distance, you want that same level of legibility (or as close to it as possible).
If you are sitting 4 times the 28 inches away (112 inches), then your display should be 4 times the height and width of a 21 inch - 84 inch diagonal. In larger rooms, that calls for some pretty big displays.
This chart - pulled with permission from the white paper makes it easy to understand. The green areas are the target screen sizes for the distances on the left. The lowest green bar, just meets the target, while the top one provides some extra readability. The blue bars above, indicate screen sizes that for the spec'd distances mean type will relatively be a good bit larger compared to that 11 point type at 28 inches...
From that, obviously, the yellows and reds indicate displays too small for real legibility.
This chart shows how well different sized displays, at different seating distances meet the Equivalent Visibility rule. Green is ideal, Blue provides some overkill, Yellow represents lower legibility, but meets the existing 4/6/8 rule for collaboration.
This makes sense, but, at the same time, consider how large you would need your display to be if people were as far back as 15-18 feet. It calls for a 150" diagonal display! Talk about huge, that's a display that's roughly 75 inches tall - yes, over 6 feet high.
In All But the Smallest Collaboration Spaces only Projectors are Really Viable.
Now, just a friendly reminder - that I'm a projector guy, so I'm a bit biased towards them inherently. The White paper doesn't get into which technology is better - various LCD displays or projectors, but I will.
Whether you stick with the 4/6/8 rule, or find that the new, more legible friendly Equivalent Visibility rule, projectors should certainly be considered, and in most cases, prove the better choice.
I can tell you that you can get LCD monitors as large as 70 or 75 inches diagonal in the low thousands of dollar range (say under $3500), but once you want larger, the prices are astronomical.
Budget Busting Large Displays: Consider, a quick search of the web (2/2016) shows a 90" LCD TV (not a professional monitor) for as low as $8000. Good luck even finding a 100" or larger. The largest these days is about 120" for an LCD TV/Monitor, but, ask yourself: Are you are looking at something that costs far more than a Tesla, or BMW 7 series? I think not, especially when there are perfectly good low cost alternatives.
A 98" LCD TV from LG currently sells for about $40,000. (What a deal - five years ago, that would have set you back around $100K.) Mind you that's a "TV". No interactivity, and no doubt missing some "commercial features" that one would expect on a large professional monitor or even a sub-$1000 business/education projector.
Consider the alternative: For less than $3000 you can put a top of the line, incredibly capable 100" fully interactive projector and whiteboard screen in your collaboration space or conference room. Don't need full interactivity, you can put in a 120" or even larger size screen, and a projector that can still be interactively controlled by tablets, and smart phones and still cost well less than $2000! On a tight budget, how about good networkable projector and a 100" screen for not much more than $1000! That's right, A fixed wall displayy (screen) for these sized rooms, and even a really well endowed projector, along with mount, will rarely cost more than $1500. With today's ultra short throw projectors installation is not much different than mounting a LCD display.
One thing that really works about projectors is that whether your area is 10x10 (or even smaller) or larger - say 20x25 feet, the costs really don't change much. You probably will spend only a few hundred dollars more for a larger screen and maybe, but probably not need to buy a more powerful projector! Your team - your users, will be able to work efficiently, thanks to the much larger displays projectors can provide.
And don't forget all of today's improvements in projectors - notably ultra short throw ones that don't blind whomever is in the front of the room whether presenting, or running a collaboration.
And then there's interactivity (often using those ultra short throw projectors. Most use pens, but more and more of today's interactive projectors can use pens, or just use your fingers. And they can record and save everything going on in the room for later distribution!
The Bottom Line: 4/6/8 vs Equivalent Visibility - Let Common Sense Rule
Personally it seems like the choice is a slam dunk. Obviously by insisting on display sizes that are larger, and therefore more legible, Equivalent Visibility makes more sense. Let's just think of it as being the more conservative approach - assuring that legibility isn't slowing down meetings and distracting from successful collaboration, or, for that matter video conferencing.
That folks covers my "translation" of the Equivalent Visibility white paper and how EV compares to 4/6/8.
But, as a projector guy, I can't resist pitching the key benefits of choosing projectors over LCD Displays in collaboration and video conferencing spaces.
As to projectors vs. LCD type monitors (alas, where have all the Plasma's gone...), as someone directly part of the projector industry, I can recommend projectors in almost all cases over monitors. Oh, there are always some trade-offs if you are dealing with under 70" sizes, but today's projectors can handle well lit conference rooms and collaboration spaces, in fact often better than monitors, simply because those monitors roll off brightness significantly if you are well off angle (colors shift too), whereas with projectors, unless you specifically choose a screen designs for a narrow seating cone (everyone between the edges of the screen), today's projector and screen combinations work well way off angle.
Finally, I will strongly recommend considering interactive projectors. They go hand in hand with collaboration. I get to use them myself in meetings from time to time, and I've reviewed quite a number of them. They are almost surprisingly easy to use in terms of all those interactive capabilities, with those interactive features allowing for on the fly changing of plans, agendas, marketing, products, etc. - basically whatever your are collaborating on. While the features are too numerous to mention here.
A recent video we did reviewing a really top of the line interactive projector (the best, most capable we've ever reviewed), devotes several minutes to its interactive capabilities.
Epson BrightLink Pro 1430Wi (Part 1)
or if you are in a hurry, and just want to see some of its interactive abilities: Epson BrightLink Pro 1430Wi (Capability Demonstrations only)
This projector in the videos is not only touch interactive and ultra short throw, but supports multiple collaborators working on the "white board" simultaneously. And it's designed to work across geography, so that multiple 1430's can be used in different offices around the country...so that when someone writes on one, it appears on all. Even better, just add a video conferencing camera to each 1430, and now you can have simultaneous video conferencing and interactive sharing across multiple offices! Well, like I said, "top of the line."
Mind you there are a wide range of interactive projectors, starting from under $1000. Really if you want your interactivity to be from using smart phones and tablets, technically interactivity starts with projectors priced around, even under $500. Ultra short throw types typically start under $1000. This top of the line, fully featured Epson, however, is in the under $3000 range, plus you'll need a Whiteboard screen, but those aren't overly expensive. Da-Lite, highly respected US company offers a combination white board - projector screen at the 94" diagonal size for right around $1000. Elite, another popular manufacturer, that makes theirs overseas, has a lower cost alternative in the form of a 96" whiteboard/screen with good ambient light rejection that sells for around $600. So, top of the line interactive projector, and 96" screen for under $3500 street price! (That sure beats a 98" LCDTV for $40,000!)
Here are some lower cost interactive projectors or projectors with optional interactivity. All of these are ultra short throw (so typically mounted right above the whiteboard/screen for easy installation). All of these use pens or touch, while just about every projector with wifi can do interactive from phones and tablets - thus these are some of the truly "serious ones"
NEC NP-UM330W Ultra Short Throw Projector Review (optional interactivity)
Epson BrightLink 585Wi Projector Review (Similar but about $1000 less than the 1430) It uses pens only, not touch, and lacks video conferencing abilities. There's also the 595Wi (has touch interactivity). BTW these can be had for around $1500 or less for schools.
Optoma is just starting to ship this one (2/2016): EH320USti We have one inbound for review. (Street price about $1800.)
Casio XJ-UT310WN Ultra Short Throw Projector Review This ultra-short throw sells for around $1800, but it's interactivity is strictly of the smartphone/tablet type. Note that this (and all Casios) use laser/led light engines so no lamps to change. If lamp based it would logically be many hundreds of dollars less.
If the budget a little tighter, but you do want pen or touch based interactivity, going short throw (instead of ultra short throw) still lets you mount the projector to the wall above the whiteboard (for easier installations). Consider projectors like Epson's Powerlite 536Wi short throw. List price is under $1600 and education price is $1250. We didn't review the 536Wi but did do its predecessor, the 436Wi here.
There are a great many projectors designed for interactivity, and literally hundreds of projectors available today that can at least do smart device based wireless interactivity. With that in mind, as the "projector guy" I have to finish with, you could buy a large monitor, but WHY?