Maintaining Contrast and Weight across Upright and Italics

Wei Huang

I've been working on some low contrast neogrotesque sans-serif designs and I noticed something that's made me question how I approach Italics:

1. The more you slant an upright font, the lighter the vertical strokes become (if measured properly, i.e. the stroke weight is measured perpendicular to the stroke direction):
   
   
   
   
2. To keep either the weight or contrast consistent across Upright and Italics, it would be necessary to compensate for the vertical strokes becoming lighter by either:
   
   1. Increasing the weight of the vertical stroke in the Italic, or
   2. Decreasing the weight of the horizontal strokes in the Italic

If neither compensation above is made, the contrast and weight changes between the upright and italics. For example in the above: the overral contrast decreases as the Italic angle increases and beyond a certain point it becomes reverse-contrast as the vertical:horizontal ratio flips.

I noticed it became an issue when I worked in the thinnest weights on a design with a fairly steep Italic (~20° degrees). Looking into a bit I could hardly find any typefaces that correct for this.

I think it's more noticeable in the extreme ends of the weights or in extreme angles:



Do you make these compensations?
I'm tempted to correct the Italics by decreasing the horizontal strokes to match as I think going by one of my previous posts it seems to be expected that Italics should be somewhat lighter than the Upright. 

Are there any pros and cons with either compensation method, or do you think it's not worth compensating at all unless the weight and/or angles are extreme? 

Up until now I haven't even really noticed when working with slighter angles so maybe it's not worth the extra work – especially if a font isn't expected to be used in high resolution/size settings like print.

Michael Vokits

Yep, you need to compensate; slanting makes strokes look thicker. Plus, italics are usually lighter also for historical reasons -- romans were held with a pen at about a 30ᵒ angle, but italics were held at a 45ᵒ angle; geometry says the 45 is going to give a thinner stroke... something hypertangent, hypotenuse, maybe a sine or too somewhere.

Michael Vokits

In other word, compensate the italic. People read in romans, and italics are secondary.

John Hudson

In a higher contrast, serif design, I usually compensate only in the ‘vertical’ strokes of the italic, and keep the hairlines the same thickness as in the roman. As Michael notes, it it traditional for italics to be slightly lighter (and more horizontally compressed) than the roman, but depending on the italic angle (seldom extreme in traditional serif types) some slight optical adjustment is helpful so that they don’t get too light.

In a design like yours, I would be inclined to adjust both the ‘vertical’ and horizontal stroke weights, making the former slightly heavier and the latter slightly lighter. Begin with the horizontals.

Wei Huang

Thinking about it some more, I think it's easier to add weight to the 'vertical' strokes in the Italics.

I also think because the Italics are slanted forwards, the optical effect of NE–SW diagonals looking slightly darker means I don't end up needing to compensate in slighter angles. 

Wei Huang

Adding some responses from Twitter:

From Ben Mitchell:

We noticed this effect recently, and decided to add a little extra weight to the verticals in the italics. Since our heavy weights have quite narrow counters, we wanted to keep their widths, which means the metrics couldn't stay quite in sync with the uprights.

From RazziaType:

For me it comes down to how  the italic works with the upright. Should it be the same overall colour, a bit lighter, much lighter etc. Increasing verticals, decreasing horizontals or both either way can all be valid options. It really depends on the optical result in the end.

From @Christoph Koeberlin:

Since I like the horizontals to stay the same in oblique-ish styles, I usually increase the weight of the verticals.

Reply from Erik Spiekermann:

you have to, or else they would look thinner.

From Very Cool Studio:

It also only became apparent to me in the extreme slants of Nudge. My eventual decision was to add weight to the stems in the middle master—where it was most noticeable. I still don’t feel settled on how to adapt the dark weights without impacting metrics.