Optical compensations and writing tools

Jasper de Waard

Hello all,

While reading this thread one the use of the term 'stroke' in typedesign, I noticed that Frode commented:

"I would absolutely a thread on the various “optical” compensations & their relationship with traditional writing tools, such as the notion horisontalz thinner than verticals look the same."

Since I am in the process of writing a thesis on a related topic, and I wholeheartedly agree with Frode, I thought I'd start such a thread here. I hope my inevitable bias will not clutter the conversation.

To start the discussion, let me ask:
1. How do writing tools, or the heritage thereof, influence our perception of letter shapes, and thus the optical compensations employed by typedesigners?
2. To what extend can we find evidence for the influence of writing tools on optical compensations in different scripts?

A non-exhaustive list of (debatable) examples:
a. Horizontals that are thinner than verticals look the same
b. Strokes in south-eastern direction that are thicker than strokes in north-eastern direction look the same (to me, at least)
c. Does b also apply to the corresponding directions of parts of a circle/curve?

Please do add questions and examples!

Jasper de Waard

@Frode : couldn't tag you in the top post for some reason

With regards to 'a', I would argue that this phenomenon might also be explained through the L-shaped vertical-horizontal illusion. We perceive vertical lines as longer than horizontal ones. This illusion, probably caused by the horizontally elongated shape of our visual field, could also create the effects we see on thickness. However, this theory fails to explain reversed contrast patterns in Arabic, for example.

Hrant Հրանդ Փափազեան Papazian

Jasper de Waard said:

To start the discussion, let me ask:
1. How do writing tools, or the heritage thereof, influence our perception of letter shapes, and thus the optical compensations employed by typedesigners?
2. To what extend can we find evidence for the influence of writing tools on optical compensations in different scripts?

A non-exhaustive list of (debatable) examples:
a. Horizontals that are thinner than verticals look the same
b. Strokes in south-eastern direction that are thicker than strokes in north-eastern direction look the same (to me, at least)
c. Does b also apply to the corresponding directions of parts of a circle/curve?

Looking forward to your thesis!

1: Chirography influences us in two ways:
— Being taught to render letters by hand makes us gravitate towards forms where the black was painted. (With the decrease in handwriting this is waning.)
— Simply being exposed to letterforms that reference particular tools (which can be effectively extinct, such as the broad-nib pen, or alive for now, such as the pixel) makes us see such forms as normal, hence generally desirable. (Fortunately the human mind –especially before puberty– can easily get used to new things.)
2. If anything this influence causes a lesser desire to optically correct; attenuating any optical ill effects of the tool is sort of the exception that proves the rule.

Concerning your list of examples, @Thomas Phinney once compiled a nice set.

Concerning writing systems that conventionally have horizontal contrast, some interesting discussion: http://typedrawers.com/discussion/2034/optical-correction-in-arabic-monoline/p1

Thomas Phinney

Some optical corrections issues: Optical Corrections (How to Tell if a Font Sucks). Also available as a YouTube video. (The version published in the print magazine version of Communication Arts has much higher res images than the online article.)

Jasper de Waard

@Hrant H. Papazian Note I am not talking about optical corrections in general, but those that may be ascribed to a writing tool, unless you think all optical corrections are writing tool related... And thanks for sharing the Arabic monoline discussion here, very relevant imo!

@Thomas Phinney the Comm Arts link is broken

Hrant Հրանդ Փափազեան Papazian

Jasper de Waard said:

unless you think all optical corrections are writing tool related...

Uh, the other way around: a tool is necessarily agnostic towards any correction, which is why a body-painting tool needs subsequent liminal optical correction. Physical tools do have optical artifacts, such as how the broad-nib pen makes lines of different thickness. To me consciously modifying the tool's application to reduce such artifacts* is against the spirit of the tool, so not a correction inherent to the tool.

* Like avoiding the "Z" coming out horrible.

https://twitter.com/hhpapazian/status/805200128193662976

John Hudson

Are we going to repeat every single Typophile discussion on TypeDrawers?

Formal writers regularly rotate the pen or brush to write Z with a thicker downstroke: that is part of the ductus of this letter, and already was when someone climbed up on a scaffold and applied a brush to the base of Trajan's column. It's not some way in which type differs from the written ductus: it is yet another way in which type follows that ductus. There is no other Latin cap that doesn't have at least one heavy stroke connecting top to bottom, so formal writers and type designers both, seeking to integrate this letter into the set, make the diagonal heavy.

Ductus is always letter-specific, and if you look at the world's writing systems and the varieties of ways in which they are written, you find very few examples of things like strict tool angle applied across all letters. Some amount of rotation is frequently married to translation, especially in terminals and joins, and then there's the bits of outline drawing in naskh and the tilting of the pen to make hairlines in nastaliq. That's all ductus, and it doesn't imply some kind of overarching 'ductal logic' to which all the letters in a script must subscribe.

AbiRasheed

I am very curious to know what people bring to this thread as I'd like to learn more about optical corrections I don't know of. For some of the questions you posed @Jasper de Waard particularly 2. I feel in writing they don't account for this at all. Why because I think 1. it has to do with the medium I guess and 2. I believe in writing there are imperfections be it L. Madarasz or R. Koch's work, there's always some imperfection and because of these imperfections, making optical corrections like we do on screen has little effect on paper because it isn't that obvious that they need to make corrections like that. Even something as basic as an overshoot is never really taken into account on paper as far as I know. Something that comes to mind where there's a huge difference is in I think the double storey g. In calligraphy there's no way you can pull that off with the same broadedge you'd use for writing other letters, you'd have to switch nibs to write a double storey g in order to drop weight like we do on screen to compensate for weight. If I'm wrong about this please cite a source just so I know they can for my own learning purposes. Other examples that come to mind, maybe strokes that meet at a point like that of V or M? It would be very hard in writing to drop weight at the meeting point like that we do on screen so easily, you'd have to rotate wrist/hand/arm to even get somewhat close to that. I think most optical corrections only make sense on screen, on paper I don't think they make any such corrections because the nib dictates what you can and cannot do, the best you could do was change angle of wrist/hand but end of the day that nib is going to do the talking. Not sure any of this completely addresses your question but figured I should just add something because I like the topic and.....because I've had a few beers.

notdef

My hypothesis is, drawing horisontals thinner than verticals and upstrokes thinner than downstrokes (I’m using “strokes” in lack of a better term — please do suggest one) are compensations done to bring monolinear designs closer to the norm of traditional Renaissance contrast patterns. Closer to what we perceive as a “normal” letter — in the West. 

Thanks for bringing up the Vertical-horizontal illusion, Jasper. It concerns over-estimating the length of a vertical line bisecting the same measured horisontal length. This seems to me slightly different than what I am talking about. 

 It is interesting to note this line in the Wikipedia article: 

People from Western cultures and people living in urban landscapes show more susceptibility than those living in eastern or open landscapes.

The article on the Müller-Lyer illusion notes a similar Western/urban inclination, and further speculates that it is influenced by the forms surrounding us daily, mainly architecture. 

What I am interested in, is understanding what illusions are influenced by our culture and the shapes that surrounds us and which are distortions of our visual system. Since seeing mainly happens in our brains, the two are most certainly intertwined and the border may not always be clear-cut.

Another example: Outside of the realms of letterforms, would we ever consider a geometrical circle not round enough? 

Jasper de Waard

Frode said:

My hypothesis is, drawing horisontals thinner than verticals and upstrokes thinner than downstrokes (I’m using “strokes” in lack of a better term — please do suggest one) are compensations done to bring monolinear designs closer to the norm of traditional Renaissance contrast patterns. Closer to what we perceive as a “normal” letter — in the West. 

In the context of monolinear designs, how about 'lines'?

This is an interesting hypothesis, and one that would have significant impact on our understanding of visual perception. Your hypothesis seems to be strengthened by the knowledge that contrast in monolinear Arabic is 'reversed'.

On the other hand, there is the vertical-horizontal illusion*, which is not exactly what you're talking about, but might help in understanding its cognitive origins. The vertical-horizontal llusion exists most strongly in a T-shaped stimulus, but importantly, the illusion remains present in an L-shaped stimulus. There are at least two biases at play here: a bisection bias (present in the T), and an anisotropy bias (present in both the T and L). The latter simply means that horizontal lines are perceived as shorter than vertical ones. The anisotropy bias is the key here.

I've done some research into it, and came to the conclusion that its cause is most likely the horizontally elongated shape of our visual field. The illusion weakens/disappears when: (1) subjects' visual fields are manipulated through special glasses, (2) you close one eye (making your visual field more circular), (3) the stimulus is looked at in the dark (because this makes the borders of the visual field imperceptible). Frankly, I don't see how the anisotropy bias would impact the length of lines, but not their thickness... Anyway, I'm designing an experiment to help clarify this, so I might know more in a few months

And then there are some cross-cultural studies. The West/East dichotomy is doubtful at best. There might be an argument to be made about dense vs open landscapes, but findings from different cross-cultural studies often seem to contradict each other. For more info, read this (p. 38). This is not to say that there are no cultural differences in perception of line thickness/length, but that the causes of these differences are still very poorly understood.

*If anyone's interested, I've written a short paper about it that I'm happy to share.

notdef

Share, please!

Jasper de Waard

@AbiRasheed: I find your paper/screen dichotomy a bit confusing, since digital type is still often printed on paper, but I get what you mean...

And I think you are right. A large part of the optical corrections we apply could not have come from calligraphy. Nevertheless, there are optical corrections, such as the thickness of vertical vs horizontal strokes, that may be derived from calligraphy. Especially interesting in this respect is: 

b. Strokes in south-eastern direction that are thicker than strokes in north-eastern direction look the same (to me, at least)

notdef

I might add to my hypothesis – for the sake of clarity, although it was mentioned before – I suspect drawing horisontals thinner than verticals (when we want them to appear monolinear) is also strongly connected to the broad-nib pen. 

Jasper de Waard

Frode said:

Share, please!

Parts of the paper may be used for publication at some point. I'll send you an email. For anyone else interested: send me a private message with your email address and you'll find it in your inbox

Jasper de Waard

John Hudson said:

Are we going to repeat every single Typophile discussion on TypeDrawers?

I don't know. Are we? 

Ductus is always letter-specific, and if you look at the world's writing systems and the varieties of ways in which they are written, you find very few examples of things like strict tool angle applied across all letters. Some amount of rotation is frequently married to translation, especially in terminals and joins, and then there's the bits of outline drawing in naskh and the tilting of the pen to make hairlines in nastaliq. That's all ductus, and it doesn't imply some kind of overarching 'ductal logic' to which all the letters in a script must subscribe.

Interesting points! Nevertheless, it was you who wrote here on typedrawers (or was it typophile? ) that Arabic monoline fonts should have 'reversed' (in relation to Latin) contrast to appear monolinear. I would assume that this is an effect of at least some underlying logic in Arabic calligraphy, no?

Nick Shinn

For those interested in the philosophy of vision, some works on perspective:

Perspective as Symbolic Form, Erwin Panofsky, 1924 (originally written in German)
The Origin of Perspective, Hugo Damisch, 1987 (originally in French)
Techniques of the Observer, Jonathan Crary, 1992

I read these a few years ago when I was particularly interested in the subject; does anyone know of any good subsequent books on the topic?

AbiRasheed

Jasper de Waard said:

b. Strokes in south-eastern direction that are thicker than strokes in north-eastern direction look the same (to me, at least)

At first I thought you meant something like a simple roman 'A' but clearly that's not what you mean. Got an example of this SE/NE stroke where it's thick for both of them? 

John Hudson

@Frode

What I am interested in, is understanding what illusions are influenced by our culture and the shapes that surrounds us and which are distortions of our visual system. Since seeing mainly happens in our brains, the two are most certainly intertwined and the border may not always be clear-cut.

Right. I know from my own experience working on scripts with varying conventional modulation patterns that over time my perception shifts to accommodate what is typical of each script.

@Jasper de Waard

Interesting points! Nevertheless, it was you who wrote here on typedrawers (or was it typophile?  ) that Arabic monoline fonts should have 'reversed' (in relation to Latin) contrast to appear monolinear. I would assume that this is an effect of at least some underlying logic in Arabic calligraphy, no?

Yes, that reflects the conventional modulation patterns of Arabic script (in the styles that I've so far seen approached in low contrast design; I don't recall ever seeing a low contrast type design on a nastaliq model, and I'm not sure it's even a possibility, given the way in which modulation happens in that style). But my point about ductus is that conventional modulation patterns are arrived at in multiple ways, even within a single style, even using a single tool. So while a script may have a dominant modulation pattern in terms of whether thicker strokes are mostly vertical or mostly horizontal, formal writers regularly employ rotation and other techniques to modulate the modulation, if you will, and that's also ductus.

Jasper de Waard

AbiRasheed said:

Jasper de Waard said:

b. Strokes in south-eastern direction that are thicker than strokes in north-eastern direction look the same (to me, at least)

At first I thought you meant something like a simple roman 'A' but clearly that's not what you mean. Got an example of this SE/NE stroke where it's thick for both of them? 

Haha, sorry if my explanation is confusing. A simple roman A is exactly what I meant, I was just trying to put it in general terms, instead of going right to an example. So, in an A, when the right stroke (SE) is thicker than the left stroke (NE), they appear to be the same thickness. This seems very calligraphic to me.

AbiRasheed

@Jasper de Waard Sorry man, I'm super confused. I can only assume you mean a sans serif A if both diagonals appear to you as having the same weight. Or if you mean like a roman square capital A, then I fail to see how it appears the same in weight.

Jasper de Waard

@AbiRasheed apologies again for the vagueness. I mean a monolinear sans-serif 'A'.

AbiRasheed

@Jasper de Waard Ah okay, no issues. I see what you mean. However, a sans serif A with little to no contrast is almost impossible(unnatural) in calligraphy IMO, unless you switched nib angles like it was freehand calligraphy. But when you do that it kinda goes against what one would call calligraphy if you ask me because calligraphy has rules and most of that adhere to some nib angle that is consistent across the board, not per letter or letters. With a sans serif, you'd have to switch nib angles on the fly and this becomes an issue if consistency is a priority which it is in calligraphy generally speaking. Just about the only nibs I know of that can do monoline work are the round tipped ones, none of that is going to yield a sharp edge as needed for a sans serif A or any other letter for that matter that need it. So, you'd have to go with a broadedge as expected, but you're still going to have to switch angles like you were left handed to write that NE stroke(what I'd call SW stroke in writing  based on the direction of the stroke). Trying to write it like the stroke is heading for NE would end up with the nib catching the paper, so you'd have to go SW. All of this to me is very non-calligraphic and uncomfortable in writing to be honest and therefore shouldn't be considered calligraphic. The moment calligraphy becomes uncomfortable where you have to twist your arm and wrist and what not to write a letter, it's a sign that there's something wrong in the calligraphy in my experience. For a sans serif A, you're gonna end up going through exactly that, a very uncomfortable experience. As an example here's an old work of mine that uses a monoline lettermark, [ConEdison] and here's one with a sans serif, [Google's G]. Was it worth it? Hell no. I had to flip the paper and what not, it was very uncomfortable and unnatural to write that out though much of it is still calligraphic. Anyhow, I'm going to guess you know all this stuff already, so I'm curious why you think a sans serif A looks calligraphic.

Nick Shinn

However, a sans serif A with little to no contrast is almost impossible(unnatural) in calligraphy IMO, unless you switched nib angles like it was freehand calligraphy. 

AbiRasheed

@Nick Shinn Yeah those are the round tipped ones I had mentioned earlier. You can't yield terminals that cut off at an angle like you would with a broad edge. With a broad edge you can get terminals like in the gif I posted but like I said the whole process is sort of unnatural, nothing adheres to an angle at all, each letter gets it's own. A broad edge wasn't meant for sans serif calligraphy, but that's the only nib I can think of that will get something close to it, not even exact, just somewhat close. Things like going from straight to curve would be problematic with a broad edge, among other issues, so while one can get something close to a sans serif, it'll never be exact without some "filling-in", once you start filling in areas, it really is not calligraphy any more. 

Kent Lew

Broad-edge pen seems like a pretty narrow definition of “calligraphic.”

A sans-serif ‘A’ seems to me like it wouldn’t be too difficult to write with a chisel-tipped instrument or a flat brush.

AbiRasheed

Broad edge is chisel tipped. I mean yeah you could sort of get close to something that looks like a sans serif with 0 contrast, but it's something of a hack really. You're going to run into issues like one of the problems I mentioned earlier or here's another one, how are you going to keep bowls monolinear with a flat tip or say drawing up a C? You can't unless you rotate the paper and even then it's messy. At some point you will be filling in areas to get it almost accurate, there's no other way around it as far as I can tell. The only way to use a flat tip to accurately write this out is if the design has some contrast, atleast medium-high. With a flat brush too I don't think you could, you'd run into the same issues irrespective of how hard or soft the brush might be. 

Ray Larabie

You can probably see more of what the original post was (I think) referring to in the sign painting profession.

Jasper de Waard

While all this talk of what can and can't be done in calligraphy is very interesting, it is not exactly what I meant when I used the term 'calligraphic' (I know, confusing). Please allow me to explain:

I'll use a monolinear 'A' as an example, but remember that this effect is the case for all (edit: most) lines with a north-eastern orientation* ( / ), versus lines with a south-eastern orientation ( \ ).

When designing a monolinear A, the left diagonal (in northeastern orientation) should be slightly thinner than the right diagonal (in south-eastern orientation), in order for both diagonals to appear to have the same thickness. (I'm assuming we agree on the sake of this explanation, but feel free to disagree.)

This is an optical correction, which implies an optical illusion. We adjust the thickness of one line, in order to compensate for the visual bias that makes one line look thicker than the other.

I am interested in the cause of this bias. Why would our visual system be set up in such a way that the A's left line appears thicker than its right line (if they are metrically equal)?

Any structural** account (i.e. the shape of our visual field, or some neural structure) seems an unlikely option in explaining such an asymmetrical visual bias.

Thus, we are left with the possibility that the bias is caused simply by our familiarity with a specific weight-distribution pattern. Namely: lines in south-eastern direction are thicker than lines in north-eastern direction. This pattern of weight-distribution I called 'calligraphic', because I assume it to originate from the constant 45° angle of the broad-nip pen. It then made its way into the first metal types, and eventually into the digital age.

From a cognitive research perspective, this seems very interesting to me. It would mean that cultural calligraphy/design traditions influence our perception of line-thickness. 

* I use orientation and direction as interchangeable words here.
** In the cognitive research sense of the word. So, non-cultural.

notdef

notdef

There are many challenges with the capital M, but I am focusing on one: It appears denser than surrounding letters when drawn with the same thickness (an optical illusion), because there is more black and less white. As illustrated above, there are multiple ways of attacking this problem. Only one of them take its cues from traditional contrast patterns.

Here’s why I think it matters to question the difference between optical illusions (distortions of our visual system), and illusions resulting from learned behaviour: Conflating “optical” and “traditional” means you run the risk of unintentionally applying traditional solutions to forms that attempt to break with, or challenge, tradition. In other words, you may get stuck in an idea of how things are supposed to look. 

Nick Shinn

Artefact arose from my consideration of why, when it had left its origins in the broad nib far behind, the didone A still observed the old “downstroke thick” practice.

Rather than just flip stress methodically, as in the notorious Italian (latterly, Karloff), I deconstructed it in a more ad hoc, subjective manner. I did though try to keep the overall effect even, resulting in a quite coarse granularity of “colour”. Release specimen from 1998: