Affinity Suite: Calculating the size of artistic text

[Pyanepsion]

v2.5.3.2516.

Hello everyone,

I’m trying to figure out how to calculate the size of an artistic text, i.e. without taking into account the top and bottom margins of the characters. Here’s the background (see attached file):

• I’m working on a document in 400 DPI, in CMYK mode, with Affinity Publisher or Affinity Designer.
• I use the Arial Regular font to write 3 texts of different lengths.
• After selecting a text, I reduce the height proportionally to 0.087 inches to meet the constraints of a printer.
• The software gives me a font size that varies greatly according to the length of the initial word:
  •   ’HEIGHT CALCULATION’ gives a size of 8.456606 pt.
  •   ’ELEPHANT’ gives a font size of 8.750799 pt.
  •   ’TEST’ gives a size of 8.462185 pt.

This variation in size obviously appears abnormal.

 

The initial aim of my research was to find the height according to the calculations taking into account the typographic properties of the Arial font provided by the Dutch software Hight-Logic FontCreator:

• Typo ascender: 1491
• Typo descender: -431
• Typo line gap: 307
• Win Ascent: 1854
• Ascender: 1854
• Descender: -434
• Line gap: 67
• Cap height: 1467
• x-height: 1062
• Vertical typo ascender: 1024
• Vertical typo descender: -1024
• Subscript horizontal font size: 1434
• Subscript vertical font size: 1331

 

Thank you in advance for your clarification and help on these two points:

1. How can we explain and correct these variations in size depending on the length of the text?

2. How can I find the height using the typographic properties of the Arial font?

useful-height.afpub

[MikeTO]

I don't believe this to be an issue, this is just due to the sizes of the various glyphs.

To calculate the font size when you only know the art text object's height, or vice versa, you'd need to look at more than the font's metrics. You'd need to look at each glyph in the text and find their maximum and minimum Y values.

[Oufti]

6 hours ago, Pyanepsion said:

[…] variations in size depending on the length of the text

As @MikeTO said, these variations don't depend on the length of the text but on the glyphs included : round letters (OCGS for example) are generally taller than rectangular letters (TEH). Triangular (AV) letters can also sometimes have a specific height (not in Arial though). 

ELEPHANT doesn't have any rounded letter (P is rounded on the side, not on the top), thus has a slightly bigger font size than your other examples for the same frame dimension (0,087" = 6,264000 pt). 

If you need an absolutely identical height for each of the Artistic Text frames, create them with the same word inside, then change its content. 

(You can observe there is also a slight misregistration between the yellow rectangle and the ELEPHANT text frame, but their height being the same this has no impact, beside visually.)

P.S. Here I aligned the rectangle and text frame on the top, and added an O in the word ELEPHANOT. You see it doesn't fit inside.

 

[Pyanepsion]

I thought glyph sizes for fonts like Arial were uniform, but I was wrong.

Thanks @MikeTO and @Oufti for your explanations.

I was looking for a formula to automatically determine the correct font size for text on the spine of a thin book. As it turns out that the size of a word actually depends on the size of each of its glyphs, this obviously makes a general calculation of the size of the words in the title impossible.

For those interested, the solution is to write the word each time in artistic text without distortion, then reduce it proportionally to the desired size, in this case 0.087 inches. It just takes a bit longer.

[Oufti]

Thank you for these additional explanations.

24 minutes ago, Pyanepsion said:

As it turns out that the size of a word actually depends on the size of each of its glyphs, this obviously makes a general calculation of the size of the words in the title impossible.

If you use only CAPS in your title, type a word with a Q inside and you'll be certain that you have place enough, since this is the tallest glyph in capitals. 
And if there is no Q in your title and you want to use the maximum size(*), just align on the O size, it will fit for all other letters.

(*) Well, almost. For a body size of 14pt, the difference in height between O and E is about 1/3 pt, i.e. 120μ. But is it really that important?

[kenmcd]

13 hours ago, Pyanepsion said:

I reduce the height proportionally to 0.087 inches to meet the constraints of a printer.

Desired Cap Height = 0.087 inches

0.087 inches × 72pts/inch = 6.264 pt (desired cap height)

UPM: 2048
Cap Height: 1467
1467 ÷ 2048 = 0.7163085938 (cap height % of em-square)

6.264 pt ÷ 0.7163085938 = 8.744834355 pt
(point size setting to get cap height of 6.264pt)

Think that should work.

 

 

[Pyanepsion]

@kenmcd, Why do you take 72 points per inch?

[Alfred]

14 minutes ago, Pyanepsion said:

@kenmcd, Why do you take 72 points per inch?

I’m not Ken (obviously!) but I’m guessing that you expect to see the value 72.27 here, which would represent pica points — traditional printer points — per inch. However, 72 points per inch is the PostScript standard.

[Pyanepsion]

@Alfred,

I tried to find out more, and found this explanation on the site of a publisher specialising in typography. It talks about all this very well. It's in French.

Point typographique et longueurs en TEX.

[Oufti]

18 hours ago, Pyanepsion said:

I tried to find out more, and found this explanation on the site of a publisher specialising in typography. It talks about all this very well. It's in French.

Point typographique et longueurs en TEX.

Excellent! Thank you. 
Jacques André is indeed a famous author, clear and precise (even if he wrote *Trimegiste instead of Trismegiste…)