I have been working on a variable typeface for a long while. One of the axes controls the x-height, so for instance, two of the masters are Regular Short, and Regular Large. To create the latter, I duplicated Regular Short Master and proportionally extended the x-height with RMX Scaler. The weird thing comes when within the last few days, I have seen how gradually more and more glyphs are not horizontally in place. For example, I didn’t change anything on the uppercase large master —as it’s not necessary—, so it shares spacing values with the short master, however, these values for some reason have changed. The funny thing is that — even if I did it by mistake — when I set the same spacing value as the short master, the large master is offset in relation to the short one. It seems like the problem is the x coordinate, but when I enter the right one, then the spacing changes back. What’s going on, is this a bug? I can send you the file for a better understanding of the issue.
I had a look at the file. I cannot reproduce anything unusual. No shifts happened to me while I had the file open. Closing and reopening did not change anything.
Keep in mind that, for the italic drawings, the skewing pivot for measuring sidebearings is half x-height. So while the italic masters with an x-height of 420 slant the LSB and RSB at 210, the masters with an x-height of 540 pivot at 270.
When you change the x-height on a master with a non-zero italic angle, and update metrics, glyphs may shift horizontally, of course.
Some components in the Black Extratall Italic are not automatically aligned.
When you change the x-height, the origin of the bounding box slants and that mean that the left and right side bearing values will change. The actual glyph outlines and coordinates are the same, but the reference from for computing the side bearing changes.
Yes, I’m using metric keys. I have already been checking that.
I’m not sure if I expressed myself about the shifting. It’s easier to see when you have the master layer visible in the background. However, what you mentioned about the skewing pivot makes sense. It’s something I thought about but was unsure of. So, let me get this right, Do I need to override the slant height? If so, how do I calculate the right x-height for the slant to pivot and where do I change it? Or, to the contrary, as I understand from Geroge’s comment in his second point, I should ignore this since the outlines and coordinates are the same, and the only change is the reference for computing the side bearings.
Thank you for the article, it is indeed clarifying, I didn’t even know about the cursivy tool!
If your x-height value is correct (matches your design) then you don’t need to change anything. Just update the metrics as you go. As long as some metrics keys point to glyphs that do not have their correct x-height yet, naturally there will be some with bad sidebearings.
I just played around with your font. I think adding a slant height will help. Set it to half of the h-height of the short masters (210 for the lighter and 220 for the heavy masters).
Thanks for your help over the weekend guys. I very much appreciate it.
I’ve been experimenting with exporting to OTF to double-check to what extent this was a problem. Although when zooming in the shift on the Uppercase spacing is little, after zooming out it’s way more noticeable. Even the vertical centre of letters like K and B shift up and down when switching from Large Italic to Short Italic Master.
Erich, I updated the metrics of the UP in the Large Master to match the Short Italic Master values. If I do it, the glyphs shift. if I don’t it’s the Metric box that shifts.
George, about the slant height, you are referring to Font Info/Masters/Metrics/Slant Height, right? Where you say h-height I guess you meant x-height. As for the values, I have been playing around and while writing these lines what I have found out is that using your values, 210 for regular and 220 for black, in the short and large masters, solves the problem. It makes sense because, after all, if I want large and short master Uppercase to have the same SB values, the slant height should also be the same. However, this has messed up my lowercase SB, which I’ll have to sort out again one by one
You don’t need to do that one by one. Open the “o”, find out how far you need to shift the outline to get equal side bearings. Then use the Transform dialog to shift all lowercase by that value.
Sorry, I meant that when testing this issue in Indesign, the glyph’s horizontal shifting between masters seems more evident when scaling down the document preview. Also, the central area of some letters like K and B slightly shifted up in the large master when observed at a small scale in ID. I have already solved this by changing the slant height.
