I've found the following poster online https://www.amazon.co.uk/Really-Useful-Piano-Poster-Beginners/dp/B07DWD25FF/ref=sr_1_7?dchild=1&keywords=THE+REALLY+USEFUL+POSTER+COMPANY&qid=1609079047&sr=8-7. Sadly, it doesn't come with the fingering for playing the different scales in multiple octaves.
What are the advantages at becoming proficient at playing the different scales in multiple octaves?
Thanks in advance :)
Basing this answer on piano - clue in question!
Playing a scale one octave only means most of the time, you'll play the highest note (r.h.) with pinky, wheras playing two, or three or more octaves necessitates 'starting again', where your thumb, usually, goes onto the tonic for the next octave each time.
So with that in mind, two octaves seem like the minimum. But why not carry on to three, or maybe four? In more advanced playing, your hands will become farther apart, so you're setting yourself up for when this happens. The arms' angles change, which means even simple scales will be played subtly differently.
From memory, I think scales on piano for exams go to three octaves in the higher grades, so that seems a reasonable target.
If, by any chance, you're considering the question relates to other instruments, there are many good reasons to play as many octaves as the instrument (and player!) are capable of.
The answer may depend on the instrument. Every instrument works based on physics and it may be harder to play notes in certain registers. This is especially true for brass and woodwind. Practicing in one octave then trying to perform the same piece an octave higher without practice could be difficult. On guitar, the frets get closer together making playing in different octaves feel different.
I see from your link that this is piano related. Even thought every octave looks (and perhaps feels) the same one thing piano players need to be able to do is shift position as they climb up and down the keyboard. This requires some dexterity and planning. So, unless the shift within the octave is identical to the shift to the next octave I'd say you need to practice at least two octaves to ensure you will be able to shift smoothly.
The poster has little numbers on the keys for the RH/LH fingerings.
It's kind of sloppy in representing the fingerings. Some like C major use the 5 finger for a one octave scale. Others like Db major give a fingering that will repeat at the octave.
You should be able to replace the 5 with 1 to get things to repeat at the octave. Ex. C major RH is given as 123,1234,5 play it multi-octave as 123,1234,123,1234. (I added the comma to show how all the scales can be played as finger groupings of 123,1234 although the tonic isn't necessarily played with finger 1 or 5.)
The poster might be helpful for the visual aspect, but I would get a better resource for fingerings. Get a method book that gives fingerings for scales in all keys, chords on all roots and inversions, and scales in double notes. Some of the fingerings for these will differ slightly from one method book to another. You might be two complementary books. Better methods will explain principles for fingerings.
Playing in all octaves and using various instruments will give your ears special experience to recognize and absorb sounds and scores. Fingering is another question: you can play it in several possible patterns and change it on different octaves, if you wish.
