Hi Mark,
Æ, æ, Œ, œ and ß are different from ‘fi’ etc., they can’t be referred to as ‘true ligatures’ anymore. They are ‘stand-alone’ characters now.
Ligatures mostly solve problems of colliding characters. If your face doesn’t suffer from such problems, then you don’t need any additional ligatures.
You might wanna take a look at this thread about f colliding with various tittles.

You're quite right of course, Florian, that ligatures solve character collision. Your f+umlauts/fj thread is very interesting too. Something I hadn't come across. (And perhaps something that as a native English speaker I was bound to overlook.)

That aside I'm still interested in other ligatures too: Those that perhaps have scant legitimacy beyond style, or what I meant by 'indulgent'. Like 'em or not.

I doubt, for instance anybody's s and t ever collide!

perhaps something that as a native English speaker I was bound to overlook.

That’s why I’ve started it. :-)

Another pointer: the thread that triggered the other one, on The Most Useful OpenType Ligatures.

You certainly have checked out some of the well-equipped OpenType text fonts that are out there, to examine which ligatures were included. It depends on the style, of course. A lot of today’s text faces are revivals of, or – in a broader sense – are based on historical models. Thus, the designers often incorporate ligatures that have also been part of the original. This can relate to linguistics as to the specific style.

One frequently sees ‘Th’, for example. Also: ch, ck, ct, st, sp.
All kinds of combinations of f and characters with ascenders, also triples like ffb, ffh, ffk. Same for long s (ſ), if you want to include that historic alternative.

An Italic may have even more. Adobe’s Garamond Premier has ta, th, us, is, ij, ll, among a lot others. Have a look at Arno, Requiem or Galliard, too.

If you can look at Mrs Eaves, I'm not sure if i've ever seen more unique triple ligatures anywhere else. I've kinda had a falling out with the typeface because of it's over/improper use, but it may be a good reference point. Some of them seem slightly (but not completely) useless, like ffy, tty, ggy, ffj, THE, and my favorite-cky. There's also the OG, OC, OO, gi, and a bunch more...

Thanks Florian. That's impressively complete. I must admit that I should've done some rummaging around inside the OpenTypes and I will now. Arno Pro is indeed a good tip which includes a lot of long s ligatures at my first glance.

I guess then, that the st, sp type ligatures are either a scribal legacy or perhaps a gratuitous flourish on part of the designer. They are certainly decorative rather than practical (i.e. to prevent collision). I wonder if they test well in terms of readability compared to their individual counterparts or whether they're best put to use at display sizes.

kai bernau's lyon italique has some great ligs worth looking at as well. love the pp lig.

Oh yes, the Mrs Eaves Just Ligatures. To be honest, to me, some of them -- in particular the capitals like MD or HE -- look like criminally designed logotypes. Can't help but smile at the g's ears in gg and gi though.

Æ, æ, Œ, and œ may be considered discretionary ligatures for Latin words such as Cæsar.
On the one hand, this is a "quaint" usage, but on the other it does aid the pronunciation of words like onomatopœia.

To be honest, to me, some of them — in particular the capitals like MD or HE — look like criminally designed logotypes.

Isn’t that half the fun of it, though? It’s amazing how a simple business card can come to life when Mrs. Eaves gets a chance to work on it. I would love to fool around with that face in metal…

Nick: "... it does aid the pronunciation of words like onomatopœia."

It may indeed aid pronunciation, but it strikes me as rather ahistorical since onomatopoeia — "oe" rather than "œ" — seems a far better-rooted transliteration of the Greek ονοματοποιία, don't you think?

Perhaps you'll think it a footling point for a quibble, but it's likely best to eschew ligation in this particular case. Pardon my digression.

...don’t you think?

The thing is, for English readers, without the benefit of accents--how does one pronounce the succession of four vowels in "-poeia"?
The dipthong œ would seem to help, as it suggests the usual pronunciation "-pee-ya", as opposed to other candidates such as "-po-ee-ya", "-po-ya", or "-po-ay-ah".

ll is nice in an italic, though I'm still searching for a good design for a double l in non-italic type. Ch / ch is nice, especially when designed so that it doesn't change spacing, so that it can be discreetly (as compared to, say, a ct lig) placed into a document. For language where ch constitutes a separate letter it's definitely an nice effect. Don't forget the capital DE ligature for Spanish, it's easy and quick to do so no reason not to include it IMO.

Olho, some of those capital ligatures have a lot of history pre-printing presses. For instance, in traditional basque writing

«El futuro es una línea tan fina que apenas nos damos cuenta de pintarla nosotros mismos». (La Luz Oscura, por Javier Guerrero)

Hmm. The Basque connection is certainly interesting. Another thing the linguistically lazy English speaker won't have come across. NA, TR and RA are quite spectacular in the graphic on that link. I think you'd need a keen eye to decipher TR which relies on the left arm of the T only and would probably look like a swash (or bastard?) lone R.

As for onomatopœia, I think Nick's closer in thinking it's an aid to pronunciation, -- Like the diæresis is in 'naïve' or 'Zoë' -- despite English being largely non-phonetic.

American usage of English seems to strip both the ae and oe digraphs and replace them with a single e. As an English English speaker I ought to object, but the lone e does make some sense to me -- though I'll admit my fusty British heritage is squealing to object as I type. In terms of visual language -- i.e. set type on the page -- I can't help preferring Words like 'Encyclopaedia' to 'Encyclopedia' and 'Encyclopædia' is even better. Also, I suppose keeping the digraph respects more faithfully the word's etymology. Things change though and as there are more Americans speaking English in the world than Brits I can't see the æ/œ digraphs surviving.

I have never seen portuguese ligatures other then the "DE", where the "E" is centered inside the "D" or united to it. Maybe there is something recently done by portuguese designers, which I am unaware.

I did a drawing with some ligatures but I am unable to upload the picture (I wonder if my uploading privileges has been revoked...).

I united the "ç" with "ã" and "õ" in a way that the lower curve of the "ç" touches the bowl of the "ã" on lower case, to form "çã" and "çõ", but it actually could be done with 3 letters: "ção" or 4 for this sillabe "ções". As for the caps, "ÇÃ" and ÇÕ" I centered "Ã" and "Õ" inside the cedilha "Ç". I did also some for "lh" and "LH", "nh" and "NH".

If these don't exist, then this tread "has already won".

I will try to upload the picture later as a addendum.

André

Mrs Eaves demonstrated that "quaints" aren't necessarily anachronisms.
Depending on circumstances, a typographer may wish to set text unmarked (crystal goblet theory) or marked. These distinctions were articulated by Johanna Drucker in "The Visible Word".
There are various ways to mark text, and the option of discetionary ligatures is one of them.
OpenType recognizes and enshrines the distinction between marked and unmarked text, in the separation of default ligatures (liga), which serve to "unmark" potentially obtrusive glyph sequences, and discretionary ligatures(dlig), which are available to add marked interest.

[edit]
Ok. I tried to upload the pictures 200 times. I don't do it. I installed Firefox and tried, no way. Then I thought, store the picture somewhere else, so it is here:

http://www.photoblog.com/storage001/2008/04/06/

I never seen anything like this.

Andre, you can't get an image to upload?

"Ligaduras Portuguesas?"

yes. I have done it, I uploaded gifs and jpgs before with no problems. In the last few days I was unable to... who knows. Thanks honey ;)

By the way, what you see here is - o que VÊs é totalmente - free. You can even modify, twist, contract, fleep over or whatver pleases you.

No EULA :)

Interesting AGL, you came up with the same solution essentially for the lh as I did for the ll, although I'm still not 100% satisfied with it (but I can't think of any other way to lig them without making it be too distracting for a reader or just not make sense). Seeing your solution and mine I think the longer serif but not connected works better. I'll try it out tomorrow and see it how looks. For now, here's my current ll, de, and ch ligatures for Spanish:

«El futuro es una línea tan fina que apenas nos damos cuenta de pintarla nosotros mismos». (La Luz Oscura, por Javier Guerrero)

I thought also about connecting the "lh" by adding a round connector like the english "ct" or "st", but it it looked kind of a "U" inverted. I guess a way to do it could be not worrying about if it would distract the reader. The "DE" that I was talking about is just like yours and it can be seen anywhere you are in Spain, just look around.

¡ awesome !

I discovered these earlier on from Prestige B and C.

As for bespoke and complimentary ligatures, there's also the Avant Garde Gothic Alternative additions to the Avant Garde family of course too.

Mark, now the trick is to get all of those same style ligatures but doing it via OpenType contextual substitutions :)

«El futuro es una línea tan fina que apenas nos damos cuenta de pintarla nosotros mismos». (La Luz Oscura, por Javier Guerrero)

I love the "AQ" in Prestige, and "LLA" "CHE", "CHA, this is great :)

I recommend using a "merged" fi-ligature only if your f and i would collide. I pretty much dislike fonts where an fi-ligature disrupts the rythm of the line (this often happens in fonts with narrow f's which would not make any trouble anyway).

Also, if you are to support extended latin (e.g. Eastern European), consider all possible f+ acute accented letter /f+ double acute accented letter diacritics combinations.

I'd suggest to include gj, gy combinations if they would collide. Especially gy looks really awkward in a number of italics.