Legibility of handakuten and dakuten in small font sizes


I occasionally come across text with a small font size where I can tell that
there's either an handakuten `゚` or a dakuten `゙` in a kana character, but I
need to zoom in to tell which one it is.

Does this problem occur only for non-native speakers, or does it occur for
native speakers as well, especially elderly ones?

Are there any other major problems with legibility with small font sizes?

If so, does the Japanese government regulate that font sizes must be of a
minimum size to be legible in any circumstance, such as safety-critical
information?




From what I can see on the net, it's mainly a problem where people don't
recognise the word.
[Here](http://komachi.yomiuri.co.jp/t/2012/0323/493704.htm?g=01) is some
discussion about why people sometimes write トビ主 rather than トピ主 - in this case
one possible is that they didn't recognise that the first part is a shortening
of トピック and so misread the word originally (apparently it's also easy to hit
the wrong key when you're adding dakuten/handakuten on a mobile phone).

I don't think it would be a problem in safety information unless there is some
special case where a misreading would cause a dangerous misunderstanding. I
can't personally think of one, and the solution would presumably be to rewrite
to avoid the potentially confusing vocabulary, rather than increasing the font
size.

In terms of displays of safety critical information, that will be defined in a
mix of ISO (international), JIS (Japanese), and similar standards, depending
on application. For example,
[here](https://www.aeha.or.jp/information/safety/pdf/guideline04.pdf) (pdf) is
a guideline for the production of the safety notices on consumer electronics,
and if you go right to the end there's a list of the appropriate ISO/JIS/etc
standards to consult for further info.

On page 19 you can see a summary and then following, some examples. For
example, in the first diagram, the top part, where it says 警告{けいこく}, should be
minimum 8mm high, the image below, which indicates danger of electric shock,
should be larger than the top part, and the explanatory text at the base
should be a minimum of 8pt/3mm high, ideally in a gothic font. There are also
guidelines for how to write the text (simple sentences of 40 characters or
less, no technical jargon, etc).




From what I can see on the net, it's mainly a problem where people don't
recognise the word.
[Here](http://komachi.yomiuri.co.jp/t/2012/0323/493704.htm?g=01) is some
discussion about why people sometimes write トビ主 rather than トピ主 - in this case
one possible is that they didn't recognise that the first part is a shortening
of トピック and so misread the word originally (apparently it's also easy to hit
the wrong key when you're adding dakuten/handakuten on a mobile phone).

I don't think it would be a problem in safety information unless there is some
special case where a misreading would cause a dangerous misunderstanding. I
can't personally think of one, and the solution would presumably be to rewrite
to avoid the potentially confusing vocabulary, rather than increasing the font
size.

In terms of displays of safety critical information, that will be defined in a
mix of ISO (international), JIS (Japanese), and similar standards, depending
on application. For example,
[here](https://www.aeha.or.jp/information/safety/pdf/guideline04.pdf) (pdf) is
a guideline for the production of the safety notices on consumer electronics,
and if you go right to the end there's a list of the appropriate ISO/JIS/etc
standards to consult for further info.

On page 19 you can see a summary and then following, some examples. For
example, in the first diagram, the top part, where it says 警告{けいこく}, should be
minimum 8mm high, the image below, which indicates danger of electric shock,
should be larger than the top part, and the explanatory text at the base
should be a minimum of 8pt/3mm high, ideally in a gothic font. There are also
guidelines for how to write the text (simple sentences of 40 characters or
less, no technical jargon, etc).

