# Illustrator

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## Ruler's odd numbering scheme?

### Mar 28, 2012 8:45 PM

(Illustrator CS5, Mac OSX)

Greetings-

I set my units for pixels, and my grid to show lines every 100 pixels. However, the rulers display the numbering in a most odd fashion. The displayed numbering goes from zero to 36, then to 72, then to 108, etc. One would think it would go in a more logical fashion, such as 50, 100, 150, 200, etc.

What is up with this odd numbering arrangement, and how do I utterly destroy it in favor of something more logical?

Thanks-

Replies
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Mar 28, 2012 9:43 PM   in reply to M_G6

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Mar 28, 2012 10:14 PM   in reply to M_G6

display the rulers then right click on the ruler to bring up a dialog to change to pixels or inches or any other unit besides points which is a per twelve incremented unit.

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Mar 29, 2012 2:13 AM   in reply to M_G6

G,

I am afraid your presuming that it is possible to make Illy make decimal gridlines with non decimal units is wishful thinking.

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Mar 29, 2012 9:25 AM   in reply to M_G6

By contrast, in Illustrator, it does not, when set to Pixels.

Correct. And there's nothing you can do about it. Illustrator has never provided for user-defined rulers.

JET

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Mar 29, 2012 12:27 PM   in reply to M_G6

M,

I'm not quite sure what you're saying,

Illy only makes decimal (divisible by ten) gridlines when the unit is decimal, in other words only for mm and cm.

This old English speaker may be writing too old English (or just replace the term old English with silly/sillily).

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Mar 29, 2012 1:21 PM   in reply to Jacob Bugge

It's because actually There Is No Such Measurement As A Pixel. How large is a pixel? How many go into a millimeter? How tall are you, in pixels? [*]

Illustrator does *not* use 'the pixel' as a valid measurement unit. It uses Points instead, and replaces the text "pt" you see on your screen with "px". And Points are, traditionally, a base-12 unit.

[*] Here is the problem. With that explanation in mind, I can tell you I am about 4989 pixels tall. Now imagine I have a 300 dpi screen, that is, when I put a ruler to the screen -- a physical one, not one on the screen -- and I count how large 300 pixels are, it will show exactly 1 inch. So then, given this relation between virtual measurement (pixels on a screen) and physical measurement (ruler in my hand, calibrated against a piece of platinum in Paris, or something like that), I can calculate how tall I am: 16.6 inch, or about 42 cm. Hmmm ... somehow there seems to be a flaw in my reasoning because that doesn't sound right at all.

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Mar 29, 2012 2:02 PM   in reply to [Jongware]

Now that was a surprise, Theunis. I thought you were at least 5184 pixels tall.

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Mar 29, 2012 2:44 PM   in reply to M_G6

M,

But that still doesn't explain why Illustrator allows one to set up a grid system based on Pixels, so you can work in Pixels, then couple that with a ruler that displays in Points?

The (non) explanation may be that it is convenient to have the unit used for web and other screen uses, and at least some time ago to show it at the original normal screen resolution, corresponding to a shown pixel size equalling the actual size of a point, which is the original Illy unit where 6/12/72 (are the only gridlines that) make sense, and then (irresistibly easy) to just treat the unit pixel in the same way.

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Mar 29, 2012 7:07 PM   in reply to M_G6

>It's because actually There Is No Such Measurement As A Pixel. How large is a pixel?

That's a separate issue. The UOM could be "carrots" and that would not prevent any decent user-defined ruler scale feature from setting the minor and major tick mark increments.

JET

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Mar 30, 2012 2:18 PM   in reply to JETalmage

Aww, come on. It's because Illustrator's "pixels" ARE just that: points, with the text "pt" replaced by "px". The odd rule and grid divison scheme flows *directly* from that.

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Mar 30, 2012 7:10 PM   in reply to [Jongware]

You're preaching to the choir (or singing to the preacher). I dare say no one here has pointed that out more than I. That doesn't change the fact that a decent user-defined rulers interface would allow the user to specify the major and minor tick mark increments, even for points.

Again, the fact that AI's so-called "pixels" UOM is really points, is a separate issue.

JET

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Mar 31, 2012 3:32 AM   in reply to M_G6

James, I must say that I am with Theunis on this.

The original OP question was dual:

(1) What is up with this odd numbering arrangement, and (2) how do I utterly destroy it in favor of something more logical?

In other words, the OP was about (1) Why (oh why), and (2) How.

Myself, I started by attempting to answer (2) by stating that it was impossible in post #4, and restating it in post #7.

M rephrased (1) in post #5, comparing with Photoshop,

...in Photoshop, when your ruler units are set to Pixels, the ruler numbering system is more logical, i.e., 0, 10, 20, 30, 40, 50, etc. By contrast, in Illustrator, it does not, when set to Pixels. This is my point.

and Theunis attempted to answer it in post #8,

and M followed it up with a question and a few comments about the explanation in post #10,

But that still doesn't explain why Illustrator allows one to set up a grid system based on Pixels, so you can work in Pixels, then couple that with a ruler that displays in Points? Perhaps there simply IS no explanation!

which I tried to answer in post #11.

This means that (1), the Why, was expressly part of the issue, both included in the OP and later posts by M.

If the rulers had been decimal in connexion with pixels, as in Photoshop, M would surely have been happy with the existing (non user defined) rulers; and this thread would never had been.

So if anything, user defined rulers might be called a separate issue.

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Mar 31, 2012 3:55 AM   in reply to Jacob Bugge

if you'll notice in Photoshop, when your ruler units are set to Pixels, the ruler numbering system is more logical, i.e., 0, 10, 20, 30, 40, 50, etc. By contrast, in Illustrator, it does not, when set to Pixels. This is my point. [emphasis added]

Jacob,

M's issue is that the numbering of "Pixels" (and Points) is fixed at increments of 72 (and divisions thereof at high zooms). That this stems from "Pixels" being nothing but a re-labeling of Points is ancilliary. One could make the very same complaint about Points, given that its major increment callouts are based on inches (both of which are legitimate units of linear measure). Someone working in Points might just as likely (and justifiably) want major callouts at every 100 points; just as someone working in inches might want major callouts at every 12 inches.

JET

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Mar 31, 2012 5:52 AM   in reply to JETalmage

James,

M's issue is that the numbering of "Pixels" (and Points) is fixed at increments of 72 (and divisions thereof at high zooms).

Indeed, but in addition M asked why, which brought up the pixel/point explanation. And M clearly just wanted the pixel unit rulers to be decimal like in Photoshop; there was no complaint about the lack of user defined rulers.

Obviously, in general, user defined rulers would form a very desirable solution to many issues, as would user defined direction of the Y axis in CS5 and quite a few other corresponding ones.

But in this specific case, the why was specifically asked about and commented upon by M, so the pixel/point explanation was quite justifiably brought up by Theunis in post #8 as clearly acknowledged by M in post #10.

Actually, I wrote post #11 to contribute to answering the first of the two questions, namely why, after posts #8 & 9 made me reread the OP and post #5, and become aware of the fact that I had failed to address it in the first place (in post #4, apart from failing to express myself modernly enough).

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Mar 31, 2012 8:31 AM   in reply to Jacob Bugge

Jacob,

I've explained my point sufficiently for all but the most brilliant among us to understand.

JET

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Mar 31, 2012 11:36 AM   in reply to M_G6

M_G6 wrote:

(Illustrator CS5, Mac OSX)

Greetings-

I set my units for pixels, and my grid to show lines every 100 pixels. However, the rulers display the numbering in a most odd fashion. The displayed numbering goes from zero to 36, then to 72, then to 108, etc. One would think it would go in a more logical fashion, such as 50, 100, 150, 200, etc.

What is up with this odd numbering arrangement, and how do I utterly destroy it in favor of something more logical?

Thanks-

Not a very elegant workaround but still a workaround is if you want metric ruler you can always set the ruler to millimeters and pretend they are pixels. For the final usage resize or output back to real dimensions.

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