Y Transparent bundle (uppercase) – The Twelve Days of Ax‑mas

On the eleventh day of ax-mas, we’re exploring the remainder of the Y Transparent bundle of axes.

Yesterday, I mentioned three:

• YTAS, for changing the y-axis transparency of the ascenders
• YTDE for changing the y-axis transparency of the descenders
• YTLC for changing the lowercase height

…but there are two more in the proposal, to round out the ways you might control vertical, negative space through individual parameters instead of a single Y Transparent axis. Those are:

• YTUC for changing the y-axis transparency of the uppercase glyphs
• YTFG for changing the y-axis transparency of the numeric figures

I’ve never had as strong of feelings as some that the lining number height should not match the uppercase, but this would let you control that independently.

Learning of these axis idea, the next question I had was: can you adjust the parameters to interpolate old style figures, since you can adjust their height? Can you adjust the uppercase height, along with other parameters, to create the small caps?

Well—not really, even if that might be the long-term vision. In practice, a lot of what the custom parametric axes of Roboto Flex and Amstelvar do works around the absence of a higher-level/lower-level axis relationship in Variable Fonts.

It seems like there is agreement that it should work this way—lower-level parametric axes become the advanced settings, higher-level axes like weight are the settings, and the style menu remains the main interface for many.

But without that high/low relationship really existing, changing a lower-level parameter like X Transparent isn’t actually changing the Width at the same time. As I understand it, a lot of duplication is happening to make Amstelvar and Roboto Flex work, and it is extremely impressive that they do in the current way custom axes work—but it also means, say, parametric OpenType lining and old style figures aren’t really parametric in the final implementation of the file. 

Similarly, switching to old style figures wouldn’t show any change to a Y Transparent Figure Height YTFG axis, as even if you wanted to make that parametric, there is no way I am aware of to have these kinds of internal changes reflected back in an axis (internally or in a UI).

Until next time,
Kenneth