I can see there are two ways of designing the “@”
One is to let the whole symbol sit a bit lower than baseline (e.g. Proxima Nova), and another one is to have the “a” inside the symbol sit on the baseline and let the tail go further (e.g. Aktiv Grotesk).
How do you decide on which way to use? Are there any rules to follow?
Also, I saw this on Wikipedia. It's a Bulgarian translation of the Manasses Chronicle (c. 1345). Seems like the “a” was
sitting on the baseline.
"The commercial at symbol is often centered optically on the lining numeral height. However, in an alternative alignment, the a-part of the character centers roughly on an average x-height."
I tend to judge its alignment and even its size upon the face I'm working on and its intended use.
Seems like aligning the at sign to the lowercase(and separately to the uppercase) would make a lot more sense to our current usage(for email address and prefix of username).
Regarding the old Agfa specs: After some research, I guess the reason why it's suggesting to place the symbol optically centered to the lining numeral is that the at symbol was used to represent the cost or weight of something. So it'd be safe to assume the character after the at symbol would always be either a number or another symbol that's placed before a number like $, or any currency symbol(which is expected to be well-aligned with numbers).
And it looks like Proxima Nova(the original was created in early 90s, I think) was designed to work the Agfa specs way. It makes sense to work better with numbers at that time.
I sometimes add a cased version to my more extensive fonts.
The very bold weights are tricky!
So that you can include email addresses in all-caps headlines, or other all-caps text.
Adobe (once you scroll past the non-Latin stuff), Font Bureau, FontFont, and House Industries generally get this right, but Linotype and Monotype forgot to update their specs for many of their recent releases.
Kinesis 3, a revision of an older design, is the only outlier.