Someone blind faces a mountain of problems. One example.
If you’re blind (or have low vision), how can you know the face value of a banknote? You can rustle it in your hands but it won’t whisper its secret.
In the UK and most countries different denominations of banknote are smaller or larger. For example, according to my tape measure, UK notes step up by 1 cm per denomination, in length and width. The 10 GB pound note is 1 cm longer and 1 cm wider than the 5 GB one for instance.
So if you are blind, and lucky enough to be presented with a large fistful of GB notes of different denominations, you can (with a bit of effort!) sort them into piles of 5, 10, 20 and 50 notes, using size comparison.
However it’s much harder in practice. What if (as is most likely) you don’t receive a fistful but only have a few notes (or just a single note) of one or two different values? You can’t do a full comparison. They might be all 10 pound notes, or some 5 and some 10 pound notes, or… You get the idea.
Of course there is plenty of modern technology that can recognize the value of banknotes. But there is also a simple, portable, inexpensive, and homespun approach, needing no special equipment and no batteries. It’s called the ‘Arthur Pearson method’, I assume after the famous blind newspaper proprietor. It uses your fingers as a gauge, i.e. as a measuring device. Here’s how it works and you may like to try it as an experiment.
Get hold of a couple of banknotes of different values. Put them on the table before you. Then shut your eyes tightly.
Place the first note, width-wise, between your index and second finger. Imagine your fingers are scissors and you want to cut the note in half.
Now use your other hand to compare the width of the note with the length of your fingers.
Then do the same with the other note.
It’s a surprisingly good way of distinguishing different values. Of course it would take practice for it to become reliable, but for me
- A 5 pound note is taller than finger 1 but shorter than finger 2
- A 10 pound note is taller than finger 1 but about the same size as finger 2
- A 20 pound note is taller than either finger.
Obviously all this will vary a lot from one person to another, but our fingers do form a rough and ready size (and therefore value) gauge for banknotes.
My fingers are too stubby to tell 20 and 50 pounds apart but I never have 50 pound notes anyway.