I am not an expert with fonts, but I do have some experience 1, and common sense. This post aims to debunk some misconceptions about font sizes!
11 px on your display is probably not 11 px on my display.
Let's do some quick math. I have two displays, 1366x768 @
21” and another with 1920x1080 @ 13”, call them
B for now.
A has 1,049,088 pixels. A pixel is a square, of
s cm. The total area covered by my 21” display
is about 1,066 cm2 (41x26). Thus,
Display A Dimensions: 1366x768 @ 21" (41x26 sq. cm) 1,049,088 s^2 = 1066 s = 0.0318 cm (side of a pixel on Display A)
Bear with me, as I repeat the number crunching for Display
Display B Dimensions: 1920x1080 @ 13" (29.5x16.5 sq. cm) 2,073,600 s^2 = 486.75 s = 0.0153 cm (side of a pixel on Display B)
The width of a pixel on Display
A is double the width of a
pixel on Display
B. The area occupied by a pixel on Display
A is 4 times the area occupied by a pixel on Display
The size of a pixel varies from display to display!
A 5x11 bitmap font on Display
A would be around 4 mm tall
whereas the same bitmap font on Display
B would be around
1.9 mm tall. A 11 px tall character on
B is visually
equivalent to a 5 px character on
A. When you view a
screenshot of Display
A on Display
B, the contents are
shrunk down by a factor of 2!
So screen resolution is not enough, how else do we measure size? Pixel Density! Keen readers will realize that the 5th grade math problem we solved up there showcases pixel density, or, pixels per cm (PPCM). Usually we deal with pixels per inch (PPI).
Note: PPI is not to be confused with DPI 2 (dots per inch). DPI is defined for printers.
In our example,
A is a 75 ppi display and
B is around
165 ppi 3. A low ppi display appears to be
‘pixelated’, because the pixels are more prominent, much
A. A higher ppi usually means you can view
larger images and render crispier fonts. The average desktop
display can stuff 100-200 pixels per inch. Smart phones
usually fall into the 400-600 ppi (XXXHDPI) category. The
human eye fails to differentiate detail past 300 ppi.
So … streaming an 8K video on a 60” TV provides the same clarity as a HD video on a smart phone?
Absolutely. Well, clarity is subjective, but the amount of detail you can discern on mobile displays has always been limited. Salty consumers of the Xperia 1 4 will say otherwise.
Maybe I will talk about font rendering in another post, but thats all for now. Don't judge a font size by its screenshot.
I'm Akshay, I go by nerd or nerdypepper on the internet.
I am a compsci undergrad, Rust programmer and an enthusiastic Vimmer. I write open-source stuff to pass time. I also design fonts: scientifica, curie.