Blapper of Water
The generally accepted method is to inverse the italics. Basically, if most of the text is not italicized, use italics to denote emphasis, but if most of the text is italicized, remove the italics to denote emphasis.
There seems to be a few reasons for this generally accepted practice. For one, it stands out better (at least imo) to use the italics / non-italics method since the letters are oriented differently. Unless you're paying close attention the slightly thicker letters are not noticeable. On forum posts in the past, I've had to edit bold formatting to italics because I realized it just was not noticeable enough. A second reason is a utlitarian / practical reason: every typeface needs a set of letters for these different formats. Some typeface sets don't support bold-italics because that's a fourth set of letters (the other three being regular, bold, and italics). A third reason would be that, when you do notice bold formatting, the bold formatting is really emphasizing. Like, almost obnoxiously putting emphasis on something. To say nothing of when it's bold-italicized.
Regardless, though, I don't see a reason to go against the grain here. Like how we use a standard indentation method...
Look at all that shiny stuff ain't they pretty
Big Catch, Sparkle Edition
A lot of books use the "non-italicized word" technique too, which is where I've learned it from personally. It's such a common trick, and that makes it another reason to use it- people can recognize the intent easier.
Currently Working On: Incorruptible Pure Pureness
The prevailing way of highlighting words in a page quote seems to be to make it non-italic while the rest of the words are italic. I never liked this style. It makes the words stand out in a bad way, as if something went wrong with the text formatting. Alternatively, one could use bolded text here to achieve the same thing in a more organic way, IMO. I am just here to confirm if I can change the former into the latter on sight or is there a policy to consider?