Text size and line height in points: Why not?

Does anyone have a really compelling argument against using points to specify text size and line height? I've been avoiding it for a long time, thinking it was just not going to give me safely consistent results, but it's starting to look like that is just the opposite of the truth.

If I size my text in pixels, it falls prey to the display resize function in Windows, and everything is converted inaccurately to point sizes. If I correct for this by sizing the text by percentages or ems, then Apple Mail and several types of webmail shrink the text, effectively passing the Windows resize problem over to several other clients.

If I set my line heights in pixels, it not only makes Outlook 2007/2010 render correctly (with and without the Windows display resize), but it doesn't seem to cause any problems anywhere else that I've seen yet (having run it through a Litmus test and checked a couple of types of webmail myself where Litmus was lagging).

So I'm asking, any good reason not to go with the points, other than avoiding that print-based form of measurement on principle?

simonpointer, 5 years ago

Hi P
In principal a screen doesn't really understand what a point is anyway, and it has to convert it to pixel in a roundabout way. pts are truely only understood by printers.

At core you should use a relative type face measure like % or em to allow your copy to scale and magnify where needed by the user.

I suspect that doesn't help because I suspect you are a designer looking for rigid consistency of typography across all client devises in the way it might work in print material. Unfortunately inconsistency and flexibility is just the way it is in web work and we have to accept it rather thane fight it.

One thing I can tell you is that you are the only person (maybe your cleints too) who will look at the mail in lots of different clients. Your users never will, so as long as it's acceptable and readable, they won't care if it is not exactly the same everywhere.

PMcKern, 5 years ago

Hi Simon,

Thanks for your response. In answer:

Designer: Yes, guilty.

Looking for rigid consistency: To the best of my ability, yes. As I understand it (having been at this game for a few years now), email design is very much a constant battle against the inconsistencies of different clients' renderings. As such, I have found relative type face declarations to be insufficiently consistent, whereas the point-size declarations, rather to my surprise, seem to do a far better job.

So I'm asking again, does anyone know a good reason (as in, it renders badly in such-and-such a client and there's a better way, or using points will actually cause more trouble than the relative sizing because [...]) not to improve the rendering of my clients' e-newsletter layouts by using this method?

Patrick McKern

davidaf davidaf, 5 years ago

Hi Patrick,

I feel this article addresses it well, http://developers.evrsoft.com/articles/pixel_vs_point_size_fonts.shtml - it could be that you feel there is more control with point sizes, but I think to summarize, the point size can vary widely across different monitors, and be unfriendly for those with accessibility issues.

The Campaign Monitor Blog – HTML email smarts to go with your good looks
PMcKern, 5 years ago

Thanks, Davida.

The problem is that what the article tells us doesn't seem to conform to what actually happens when you adjust the text size settings in a browser, as far as I can see (nor is it easy to tell if the author is coming down on the side of design integrity or flexibility for greater accessibility...).

At any rate, what I can see is that relative sizing (%, em, #) allows text to be resized independently of the design environment around it. I can imagine that this is a good thing to many people who don't care about the design and are quite ready to blame the designer for not making columns to fit the text at any size that they care to make it.

On the other hand, it would seem that both pixel- and point-sized text retain their size in relation to the design around them, contrary to what Jennifer Kyrnin's warning. I would personally prefer to stick to this paradigm and let people use the zoom control to cover their accessibility issues. This is exactly the kind of thing that we're trying to do by controlling webkit resizing (and by the way, CM's website is using absolute pixel heights).

So again, what I'm seeing is that point-sizing, contrary to what I would have thought, what I've been taught, and what I keep being told, behaves much the same as pixel-sizing, but with more consistent results across the board. I do worry that A) I'm missing something that no one has managed to communicate yet, or B) that browsers and/or email programs may choose to start treating point-sizing differently at some point, but really, if they can't treat pixel-sizing as consistently now, should I be waiting around until they do?

PMcKern, 5 years ago

Okay, that's not fair: It's Outlook that has issues with pixels, and I can't reconcile that with other clients' inconsistent approach to the relative sizes. I'd like to have a way to set a base font size that applies well to Outlook (requiring point sizes) but using pixels for the rest of the world. I don't see how I can have it both ways, but at the moment, playing it Outlook's way doesn't seem to be a problem for anyone else. As far as I can see. Ready to be proven wrong.


200,000 companies around the world can't be wrong.

From Australia to Zimbabwe, and everywhere in between, companies count on 
Campaign Monitor for email campaigns that drive real business results.

Get started for free