Podcast: Does Font Size Matter?

Operator Training: Does Font Size Matter?

Nov. 29, 2023
Consider contrast, font color, and size, as well as background colors, to ensure operators can do their jobs well and without fatigue.

In this episode of Chemical Processing's Distilled Podcast, host Traci Purdum and guest Dave Strobhar, founder of Beville Engineering, discuss the importance of font size in operator training. They highlight concerns related to small font sizes on computer monitors used in control rooms, particularly with the increasing resolution of displays. Strobhar mentions the military's Mill Standard 1472, specifying preferred character heights for legibility and readability. The conversation covers issues related to contrast, font color, and background colors. Strobhar emphasizes the impact on operator fatigue and accessibility, especially for aging operators wearing bifocals.


Traci: Welcome to the operator training edition of Chemical Processing's Distilled Podcast. This podcast in its transcript can be found at chemicalprocessing.com. I'm Traci Purdum, Editor-In-Chief of Chemical Processing, and joining me is Dave Strobhar, founder and principal human factors engineer for Beville Engineering.

Dave is also the founder of the Center for Operator Performance. Welcome back, Dave. How are you?

Dave: I'm doing great. Traci, fall is upon us, I think.

Traci: Have you survived the time change?

Dave: Yes. I didn't even notice the time change because all the clocks that I use are based on computers, and they automatically made the change for me.

Traci: It is amazing, and my car does that as well, but when it gets dark at like 5:30, I think it's like 10 o'clock and ready for bed. So that's the only indicator now. As an old person, that's my indicator.

Dave: Well, it's a little confusing. Yeah, for a while.

Traci: And speaking of old people, in today's episode, we're going to be discussing font size. And this is something near and dear to my heart because as we speak, I have three pairs of reading glasses on my desk, and I have been known to take pictures of labels and menus with my phone so that I can blow it up. So, font size is pretty important. And I wanted to ask you, where specifically is there a concern for font size?

Dave: Well, so as you say, I've gone through the same sort of issues that you've gone through as far as needing the reading glasses, but the major concern is on the displays that the operator is expected to utilize. And what we're finding is that the font size is actually getting smaller over time. In the early days of distributed control, you had full-size font or half-size font. There was not an ability to choose how many do I needed, 10 point or 12 point or whatever size font. But now you have that option. And what happens is as you increase the resolution on a computer monitor, the font gets smaller because resolutions based on pixels per inch. So, the greater resolution, the more pixels per inch.

So, the font, when you talk about a 12-point font, that means 12 pixels, 10-point fonts, 10 pixels. So, if I have more pixels per inch to get better resolution, the font actually gets smaller in terms of its absolute height, even though it's still 12 pixels high. It's not as high to the eye. So, in these displays, the operators are now having to contend with very small numbers, and of course, what do we have console operators for but to read and interpret those numbers, and we have made it harder for them to do that by ignoring the font size issue.

Traci: Is there a preferred font size? I mean, is there a standard, I guess is what I'm asking?

Dave: Yes. So the military some years ago came out with a, it's called the Mill Standard 1472, and I think they're up to version G now. And they give you the formula for calculating the height of a character. They don't call it font size, but they say, oh, it needs to be an eighth of an inch or a quarter of an inch, or whatever that you would want to have. And so, there is a standard out there and they actually have it for two different situations. One is legibility, can I even tell that it's a number versus a letter, or can I distinguish a three from an eight or a five?

But then there's readability that I actually want to be able to read it and it needs to be a little larger for that readability. So, the Air Force came out with this standard, the Department of Defense, and it's quite common now to find graphic displays that operators are using that fall below the minimum.

So they're not even at the preferred or recommended. They're not even at the minimum height requirement for the size of the font. And that's something that you would think is ... how does that happen and shouldn't it be easy to fix? But what you find is, of course, some of it has to do with you're used to your screen and you say, well, I write a letter and I use 12-point font or 11-point font, and it seems fine to me, but you, of course, are probably sitting closer to your monitor than an operator would be in a control room who might be pushed back from it a little bit and still looking at the displays that's going there. So, people take what they think is their preference and then applying it to the graphic displays. And then you put it on this very high resolution monitor and it gets even smaller. And so now you have a font that is below the standard for readability and legibility.

Traci: You brought up the monitor, and as I'm looking at my own computer monitor, I blow it up. It's at 200%, but there's a risk with that because then some things are not visible to me anymore. Can operators do that in control rooms? Can they make adjustments to what they see to make it bigger so that they can see it better?

Dave: They can't. They're stuck. They're stuck with what they have. And in some of the systems, you say, well, okay, our font is too small. Well, let's just go. And like you would do on your computer, you would just go up and click and say, I want this larger font. The trouble is on many of these control systems, you have to do it on each and every instance where you use it. There's no global setting that says, I want to use this size font everywhere. And so if you've already built the system to go back in and correct the font requires that somebody touch every single instance where it's used to reconfigure the size of it.

So, it's a tedious and potentially long process to make that change because they can't blow it up. And then what you find now is that many of the systems enable you to ... you can't blow up a section of the display, but I can window them into a monitor and shrink them down. I have to shrink the whole thing down. So, I have a case where I had a display that was barely legible when it was full size, and now they're just shrinking it down to a quarter of what it was, in which case you have to be inches away from the monitor in order to be able to read anything.

So, it's a problem that's been compounding over time, and a lot of it with that sort of technology that people think, oh, well, higher resolution, that's good. Yes, it is, the ability to put multiple displays on a large monitor. That's good. Yes, it is. But you have to then also recognize what's happening with that change that you're making. And in some cases, again, you may be making it very difficult to read a particular value and make the proper interpretation.

Traci: Now, what about font color and background colors? Are there standards for that or suggestions?

Dave: Well, there's suggestions, and the key thing here is contrast. You want a good contrast between the foreground, the font, and the background that's there. And so black on white or white on black, that's going to give you the greatest contrast for doing it. There's been a move to what is called the gray screens. And so instead of using a black background, it has become common to use a gray background of various shades, and then you need to adjust the font so that you get a good contrast.

One major company they had all-black backgrounds screens, and their font was in cyan, the light blue color that is programmed on your computer. And so, you had a pretty good contrast ratio. You had this light font against a background that was very dark, and so you could see it. Well, when it came out and somebody said, Hey, we need to go to these gray backgrounds. They changed the background color, but they didn't change the font color. So, you had a situation where I had a very poor contrast, and looking at those displays, I thought I was going to go blind after a couple hours because you had to really strain to be able to see that light cyan against the light grade background that they were using. So, contrast ratio is key. It doesn't really matter what combination you use as long as the contrast is good. Color does take a little bit more ...

It's actually recommended that with color, you even use a slightly larger size font than if you were just using a black and white. And some of that has to do with our visual acuity for color isn't as crisp as it is for the black and white, the way the eye works. So blues for example, tend to get a little fuzzy around the edges. So the recommendation is that if you're actually using colored colored font, that it'd be a little bit larger than just the black or white font that you used to have.

Traci: I can certainly attest to when you were talking about the background colors, black or gray. And I have software that I use to edit these podcasts, and one brand of software has the black background and another brand has a gray background. And I prefer using that one because it's just so much easier on me to see where I'm going and what I need to cut rather than that black. The contrast of that black is just too much for me, so I'm glad I'm not alone on that.

Dave: Yes, and that's where people often don't think about that and they just say, oh, well, it doesn't really matter. But particularly you have these console operators, they're watching these screens for 12 hours a day. And so some of these items, people say, oh, well, who caress about font or size or color? You sat in front of it for 12 hours. You would start to say, Hey, I'd like to make this a little bit easier on myself.

And also, then from the company standpoint, I don't want them to misinterpret what they are seeing and react inappropriately, either do the wrong thing or fail to react because as I said, they mistook a three for an eight because it was a little bit small and a little bit harder to read.

Traci: And also taking into consideration the fatigue that it causes the operator. You can get a headache from that. You are just not thinking clearly sometimes if you're in that kind of discomfort. So good things to think about. Are there any other accessibility concerns to consider? We're talking about the visuals, but are there other things to consider?

Dave: Well, so you brought up at the beginning about using reading glasses now, and I use reading glasses as well, but as we age, obviously, we tend to lose some of the visual acuity that we had in our younger days. And so you have issues where a lot of operators, they wear bifocals. And so the question becomes, well, if I start stacking the monitor, so I put one monitor on top of the other one, well, now in order for the bifocal to get the upper monitor in sight, the operator has to tip their head significantly back almost looking at the ceiling in order for the lower portion of their bifocals to pick up what's on the screen. So, there's not just the size, but how it's placed.

And again, it's detrimental to people as they age where I can't see that very well because it's higher and I need my bifocals. And again, the way most monitors and desks are made today, they really don't fit the general recommended practice in terms of where you would place things. They're just placed on a desk like we do in our offices, but that's not optimal in terms of where your line of sight is and where you would want to actually place a display for somebody.

So the problem in terms of being able to read and do my job becomes more difficult as I age. And if I'm using these stack monitors, it just makes it worse.

Traci: A lot of things to consider that you don't really think about, but then when you do start thinking about it's like that makes perfect sense. Is there anything you want to add on this topic?

Dave: I think the main thing is that oftentimes people consider the ... well, that the operator in front of a monitor is just like they are at their workstation, but they're not. In other words, they have multiple monitors. They're in a control room, they're not going to be sitting at a 90-degree angle right up against the desk for those 12 hours. You need to account for the fact that they are going to be a little bit mobile, and you need to bring that into the display design and say, okay, let's make this a little bit easier to read by just making the font bigger. And it's a very simple thing to do. So here's a case where the solution is not hard. Well, what do we do? Make the font bigger. It's difficult on an existing system because I said you have to go in and do each one, but the fact that it continues to propagate is rather surprising in this day and age when we can make it so much easier for the operator to do their job.

Traci: Well, Dave, thanks for helping us get through that age-old question, does font size matter? It sure does. Right.

Dave: Well, it sounds like a boring topic, Traci, but there's actually a documentary out there on Helvetica text, so apparently somebody thought it was worth actually putting a documentary together on it, and it does matter.

Traci: Absolutely. And I'm going to go check out that documentary. Well, folks, if you want to stay on top of operator training and performance, subscribe to this free podcast via your favorite podcast platform to learn best practices and keen insight.

You can also visit us at chemicalprocessing.com for more tools and resources aimed at helping you achieve success. On behalf of Dave, I'm Traci, and this is the operator training edition of the Distilled Podcast. Thanks, Dave.

Dave: Thanks, Traci. Appreciate it.

About the Author

Traci Purdum | Editor-in-Chief

Traci Purdum, an award-winning business journalist with extensive experience covering manufacturing and management issues, is a graduate of the Kent State University School of Journalism and Mass Communication, Kent, Ohio, and an alumnus of the Wharton Seminar for Business Journalists, Wharton School of Business, University of Pennsylvania, Philadelphia.

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