Font book: duplicates are not actually duplicates

Question

I have a problem when installing new fonts on Font book. I'm want to use this font: https://github.com/sunaku/tamzen-font, following the doc I download the zip, extract it and drag & drop all of the content of the /ttf folder into the app Font Book.

The problem is that of all the different font sizes available in the /ttf folder, when I try to select on of the new font, apps (like iTerm) recognise only one: TamzenForPowerline

In Font book all the different variants of the font are marked as duplicated, even though they are not (as you can see from the image the fonts are different):

Now, how can I tell Font book that those font are actually different?

Answer 1

this is based on bitmap fonts (OTB) which in the past where optimised for a certain font size. This is not a font family. Therefore the Font ID - which is used by Fontbook to identify fonts - of each of them is the same. You could use e.g. FontForge to change the ID, but for a variety of reasons I wouldn’t recommend that. Why not use a vectorbased, monospaced font? There are lots available for free including bitmap-like looking ones e.g. here, here or here.