Universal "x-factor"

Hello Typophiles:

Just wondering if anyone knows the history of any proposals that may have been made in the past to systematize a universal "x-factor" for typefaces that would allow easy calculation of ideal body text sizing? (Searching the forums didn't reveal any hits...)

For example:
If we just hypothetically used Helvetica 55 as the universal standard yardstick (since it's so ubiquitous), we could give this font an "x-factor" of 1.000 and then assign an x-factor to all other fonts based on the ratio of their x-heights to Helvetica's (using 1000 UPM measurements).

714 (ascend) + 286 (descend) = 1000 UPM
517 = x-height

Times New Roman:
717 (ascend) + 283 (descend) = 1000 UPM
461 = x-height

So, the "x-factor" of Times New Roman compared to Helvetica would be:
517 / 461 = 1.122.

Therefore, if you regularly set Helvetica at 10 points, then you would set Times at 11.25:
10 * 1.122 = 11.25 (rounded to nearest 1/4 point)

If this x-factor number were published with fonts, it might make it easier to help non-techie and non-designer font users make better sizing choices instead of resorting to naming solutions like "Baskerville 10" to show intent at 10-point size...

brianskywalker's picture

This would be quite useful. I think CSS has an x-height adjust for adjusting font size without adjusting "font-size". Never seen anyone use it.

Nick Shinn's picture

Not practical.

Leading, x-height and copy-fitting are co-dependent.
If you equalize x-height by bumping up the size of the smaller x-heighted face, then it will become too tightly leaded (fitting the same amount of copy in the same space) or will require more space (with the same proportion of leading).

Try it with Helvetica and Futura.

Stephen Coles's picture

Jorge de Buen has proposed a “new typometry”. He spoke about it at ATypI in 2003 and parts of his thesis were published in SOTA’s journal Interrobang, the third issue.

Mel N. Collie's picture

CSS has an adjustment for between preferred and fall back font that is not supported by IEx. Meta data containing x ht and aspect ratio to a standard would be nice, but I'd suggest verdana, not helv. as the measuring schtick. There is only 1 verdana.

Theunis de Jong's picture

I agree with Nick -- not practical. Fonts have more dimensions than just an x-height.

Never seen a PDF with Adobe-Sans / Adobe-Serif font substitution? It's horrible. I'd rather have the old Courier.

Mel N. Collie's picture

Maybe true TdJ, but when adaptive layout meets typography, people and programs need to know somehow, what the aspect ratio and relative xht are.. Its just like in the olden days, before the pour and print of wysiwyg.

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