Formula for Font Height

[dmot]

I know there is a formula to size a screen for a projection system.

Is there a formula to size fonts?


With 70" LED Flat Screens now becoming common and affordable I got to thinking. If 95% of our use of a projection system is text over stills or video, wouldn't a text size formula be even more important than screen height? I know that there are recommended font sizes but that seems silly because it depends on other factors as to how big they actually appear on screen. I guess I'm wondering if the clarity and brightness of an LED would make up for the difference in size in a small venue.

(It's approximately 42' from screen to farthest viewer and our screen is currently just under 5' high. Not quite the right size but close to the 1/8. Also, aware that the 70" units I'm seeing are not commercial units but just trying to think down the road a bit.)

[Paris MkVI]

Just remember that if you install consumer units in your church, the manufacturer will consider that commercial use and likely void the warranty immediately.

Quite frankly, the rule-of-thumb for us is, what can the pastor with the worst vision read on the screen? That's the size we go with, as long as things don't get extreme. Basically, we moved from 32 lines to 38 lines (standard def) to accommodate our senior pastor.

We also avoid serifed font styles as much as possible, to improve detail clarity and legibility. Serifs are fine for print - not so much for projection.

[petereit]

I just read that Guy Kawasaki uses Steve Jobs' old rule of thumb. Take the age of the oldest person in the room and divide by two. That's your *minimum* point size. Yes, I know, font size can be subjective and that doesn't factor in screen size or distance factors, but who am I to argue with the masters of presentation?

[Gracetech]

Found this with a bit of searchfu.

The quick rule of thumb is to take the FURTHEST distance and divide by 8. This will give you the needed screen HEIGHT (regardless of aspect ratio). It's unclear from your diagram if this distance is 85' or 85' + the depth of the bleachers.

If it's 85' then a 9' high screen would be sufficient.
(4:3 aspect would be 9x12)

If it's closer to 100' then a 12' high screen would be needed.
(4:3 aspect would be 12x16)

Of course if you are using the screens for IMag then i usually go a tad bigger.

crt

[dmot]

Appreciate the responses.

Paris - I like that "worst eyesight" technique. Unfortunately that only works with a currently installed system. I have gone to stores and stepped off the distance, then noticed how easy it was to read text, but I don't have as much confidence in that.

Petereit - We use Tahoma at 40 so we got it covered. Kawasaki has 10-20-30 rule which was no more than 10 slides, no longer than 20 minutes and no font smaller than 30 points. I like no more than 4 lines on any slide so my 40 usually works. I think Guy's formula is a good rule of thumb but there are creative exceptions.

Chad - As I stated in my first post, it isn't screen size that I am wondering about. There are good threads on that in this forum. My question regards actual font height in relation to distance. I stated that this would be for projection of text 95% of the time. I'm guessing that if you used a lot of video or imag the screen height factor would come into play.



What I am interested in is a formula that would go something like this.

Distance in feet from screen to furthest viewer/8 = Minimum font height in inches.

Minimum Font height/3 = Minimum distance between lines


In this scenario if it was 48' from screen to farthest viewer the minimum font height would be 48/8 = 6 inches. And the distance between lines would be 6/3 = 2 inches.
Therefore, if I wanted 4 lines of text it would require 24 inches for the lines and 10 inches between lines for a total screen height of 34 inches.

[Gracetech]

Sorry i was trying to make a point without actually making a point.

You can't take font size into account unless your screen size is right for the room. In one of our rooms we can't go below 68pt in another room we can use 30pt font and it looks the exact same size at the back of the room.

So as long as your projection is sized right you should be in the 30-40pt size at a minimum.

crt

[dmot]

Chad - Is that true? It seems like you could have the screen height right but the font size would depend on the resolution you were running.

[Gracetech]

You are correct the screen resolution will affect the results. I just left that out of the equation and used like resolution but different size.

Another thing that people often don't think about is brightness affecting viewable font size. The dimmer the light on the screen the harder to make out edges and outlines making it necessary to increase the font size.

Some one needs to come up with an all in one tool that can take in all the variables and then give you a slider so you can fine adjust some variables so that you can end up with your ideal setup. I've seen bits and pieces of this in different apps but not all in the same app.

crt

[daver2]

And then the background and font colour also has an effect.

I am green/blue colour blind and we have one pastor who thinks these are a great colour combination to use together - wrong!

Dave

[dmot]

Guy Kawasaki recently had a bog about things he learned from Steve Jobs.

6. You can’t go wrong with big graphics and big fonts

Take a look at Steve’s slides. The font is 60 points. There’s usually one big screenshot or graphic. Look at other tech speaker’s slides—even the ones who have seen Steve in action. The font is eight points, and there are no graphics. So many people say that Steve was the world’s greatest product introduction guy...don’t you wonder why more people don’t copy his style?