To insert these chords directly into InDesign, that is, in between other ordinary text fonts, I have been obliged to use Microsoft Word to write them, export them as PDF, then in Illustrator convert them to Outline and save as .ai files with PDF compatibility checked before inserting them as anchored inline frames in InDesign.
Is this «special» font OpenType, TrueType or PostScript?
As far as i know, Sibelius also can export TIFF/JPG/PNG and PDF. Give it a try.
The problem with Sibelius exports is that it exports the whole page and then masks the undesired part outside of the selection with white rectangles, pretty lame as it requires extra work in Illustrator to Convert to Outlines > isolate the needed part > Expand > copy to new document > export as AI with PDF compatibility and insert it in the InDesign document.
If this font could just work in InDesign it would be great.
The font file I installed was an .otf and in Finder I see OpenType® font.
It sounds like this font has some new features not found in contemporary fonts, but how does Sibelius create these chord symbols? Does it create type from the notes you put in, or do you type the chord symbols? I mean, if you're in C, and you enter C-E-F#-Bb, does it know that's a C7#11 and that if the F# were a Gb it's a C7b5, or do you have to type that yourself? It may help understand why typing this font into InDesign isn't working.
You might consider making a text frame that you can insert as an inline object. In this example, I have used a combination of Superscript, Subscript and Kerning. I don't have any music fonts for the accidentals on this computer, but you get the idea.
It changes the font in the Chord Symbol Text Style (if you are familiar with Sibelius) and it just works (as long as legacy chord input is enabled). In the end it is just a font with many switches.
You can see that it works a bit but not fully.
I am also attaching the picture of the OpenType features InDesign sees for this font.
It looks like Sibelius is placing the flat under the 5, and then moving it back under the sharp when the 3 is entered. I couldn't say how Sibelius is doing that. It could be a ligature, the way f and l or f and i typed as individual glyphs can be substituted for a combined glyph, as in this example:
Maybe when you enter the flat and then the 3, it's substituting a combined glyph instead. You can check this by going to Type>Glyphs and seeing if there are any ligatures of flat with 3. That's just a shot in the dark, though. It could be done with kerning that Sibelius is designed to do automatically, but I wouldn't know that either. Although it would be easier to just type it, making character styles for positioning would make the whole thing fairly easy to apply.
I have checked in the Glyphs that compose the fonts and there is no ligature like you suggest.
Talking with the font designer he said that the font is doing all the work. Sibelius has absolutely nothing to do with the shaping, substitution or positioning of the characters, other than the fact that (on the positive end) Sibelius is actually capable of translating exactly what the font's output should be, even if it's a visually quirky during entry.
It seems that InDesign is not up to date with supporting fonts that have a somewhat complex behaviour.
Curiously, InDesign is handling this font fine as long as I do not go beyond one single modifier of the main letter (example slashed V, realised by writing Vk) and one accidental column. After that it just cannot understand it, but Sibelius, which is by no mean an application dedicated to font-work, is reading it just fine.
I have to say I am pretty disappointed by this because, as far as I know, InDesign is THE professional application for desktop publishing and if it cannot properly use certain fonts, this is something that the devs should be made aware of and possibly find a fix.
Is there any way one can make this known?
You should report this as a bug. It’s beyond my understanding, but if you give all of the details, and contact info for the font designer, maybe you can get help.