taller x-heights for bolder weights

Austin Stahl

I'm working on my first multi-weight family, and I've noticed that in some families, the x-height gets slightly taller as the weights get bolder; in many, the x-height stays consistent throughout. I'm curious: how do you decide whether to do this? Is it just a "make it feel right" type of thing, or are there specific considerations you take into account?

Chris Lozos

The x-height is adjusted so that the bolder weights look correct with the lighter weights.  It is normal to slightly increase x-height as a face gets bolder to optically correct for the illusion.

Austin Stahl

Yeah, I understand the basic reason why -- but I've been taking a closer look at a bunch of fonts this morning and finding it's about 50/50 as to whether this is done or not, just in my quick random survey.

Chris Lozos

It is not required, but like many things in type, designers differ in approach.
When I used type that was not corrected for in this way, I would bump up the point size of a bold that was set next to a regular and looked small to the eye.

Victoria Rushton

I don't have a more specific way of doing this other than proofing paragraphs of your light weight in the recommended pt size, with some words of phrases in bold, and seeing what looks best. But as I understand it, the answer always seems to be that the x-height needs to get a little taller as the weight increases. 

James Puckett

The taller your x-height is the easier it is to get away with not increasing it.

Also, I think matched x-heights have become more common in the last decade because people wanted matched heights on screens, where varied x-heights don't always line up in text.