QR codes written in upper case are often faster to scan
Why is my QR code link all in uppercase?
QR codes are often not very efficiently made. The more data you put into the QR code, and the less efficiently it's encoded, the closer you have to be to scan it.
See how far away you can scan this QR code from:
QR codes have a couple different encoding modes.
Modes we can use to encode a string in a more efficient way.
Models are automatically selected by QR code generators to be as efficient as possible, but since we can control the input data, we can make sure to maximize our use of more efficient encodings.
A list of supported modes are shown in the table below:
| Mode | Characters | Compression |
|---|---|---|
| Numeric | 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 | 3 characters are represented by 10 bits |
| Alphanumeric | 0–9, A–Z (upper-case only), space, $, %, *, +, -, ., /, : | 2 characters are represented by 11 bits |
| Kanji | Characters from the Shift JIS system based on JIS X 0208 | 2 kanji are represented by 13 bits |
| Byte | Characters from the ISO/IEC 8859-1 character set | Each characters are represented by 8 bits |
sources: https://en.wikipedia.org/wiki/QR_code#Design
https://www.npmjs.com/package/qrcode#encoding-modes
What we're interested in is actually Alphanumeric, since it includes a couple extra useful things, namely: / . : Which, in addition to letters, is all you need to make a URL.
But, instead of 8 bits per character for the standard ISO set, we use 11 bits for 2 characters. An average of 5.5 bits per character. 69% of the bits per character.
That makes our URL just small enough to fit in the minimum QR code size, which has 21 total columns, or easier to count, 5 columns / rows between the position markers that take up the 3 corners.
Domains aren't case sensitive. Most web servers don't care about the casing of the path, though some services like YouTube might care for the randomly generated IDs.
So we can write out our domain as HTTPS://BLOG.JAKEM.DEV/QR
And it’ll be easier to scan from further away.
What else can we do? I guess we could increase the contrast ratio.
