Hairline Outlines in Illustrator

[TimCreateALase]

How do I create a Hairline outline in ai? I am printing to a laser that only accepts colour as raster to engrave and a hairline RGB Red as vector to cut along. The 0.1mm stroke does not work.

[Steve Fairbairn]

Turn off Align to Pixel Grid and you can make strokes of any weight.

[Monika Gause · Accepted solution]

The pathfinder "Outline" creates strokes of 0 Pt, which are in fact Hairlines. Create a graphic style out of this and apply to your stroke.

[TimCreateALase]

Wow that worked. My machine now cuts the line instead of raster. Thank you

[Guest]

Monika, has this always been the intended use of the Outline pathfinder, and I've just never known it?! All these years I wondered. Do you know of other uses for this command?

Also, I'd always been taught that .25 points is a hairline and that 0 points simply doesn't register (won't print). I think what you're saying is that a 0 point stroke is in fact a hairline – not .25 – and 0 points will in fact output, yes?

[JETalmage]

Hairlines are not even supposed to be "legal" in Illustrator. I've been pointing out this bug in Pathfinders in this forum for years.

Being "disallowed" in Illustrator (you can't expressly set a stroke weight to zero in Illustrator), hairlines occur accidently when Pathfinder operations break Illustrator's own "rules" and create them. Because of Illustrator's anti-aliasing, the hairlines can easily go unnoticed (especially if a light color) and can (and no doubt have) wreck printing jobs.

Just more Illustrator sloppiness. Again, Adobe has known about this issue for years and years.

JET

[Monika Gause]

Doug, when you simply assign a 0 Pt stroke, it's the same as assigning None. Only when using this pathfinder, you'll get the hairline stroke.

[Kurt Gold]

You can also make them by enterring 0,0001 pt in the stroke weight input field.

[Guest]

Thank you all. But I'm still unclear:

(1) what a 0 pt (or 0.0001 pt) stroke weight is used for, especially if it's barely detectable (I supposed depending on the function and precision of the output device)

(2) what such lightweight strokes accomplish that a .25 stroke weight won't (especially since a .25 stroke is "less barely detectable" and is legal in Illustrator)

(3) when one would ever use the Outline pathfinder command (other than in the OP's case).

Thanks.

[JETalmage]

Doug,

A true hairline always prints and displays as the thinest width that the output device can render. I use them all the time in programs which properly provide them.

In FreeHand, I have always set my default working style to black hairline, no fill. This lets me draw paths accurately at any zoom without ever having the path display become fat and bulky. (Yes, in actual preview mode--no one needs to trot out Illustrator's hideous "outline mode," which is merely an archaic workaround for this omission and other basic shortcomings of Illustrator.)

Working this way is also advantageous for paths drawn as temporary construction aids. That is, they always display as the thinnest path possible on screen, but without having to be converted to pathGuides.

In FreeHand, I've always drawn my custom printer marks (crops/folds) in the bleed area as hairlines, and also use hairlines for die cut outlines.

In short, hairlines by their nature are advantageous anytime you want to draw, construct, and convey things with a working feel and visual display of maximum accuracy.

Merely setting very thin strokes is an unsatisfying workaround for this hugely practical feature. True hairline stroke settings should be standard fare in any decent drawing program.

JET

[Guest]

This makes sense, JET. So hairline isn't defined as a software stroke width setting, but rather by the limits of the output device. Put another way, a hairline on one device may very well be a different stroke weight than a hairline on another device. OK. Now I'm getting somewhere.

Been a while since I was in FreeHand. Do I recall incorrectly that a hairline in that program is .25 points? Or is that a setting I learned from Olav to define a hairline stroke? An old idea that's no longer necessary? With today's technology, it can be set at 0 (or 0.0001)?

[Monika Gause]

In FreeHand the option is called "Hairline" in the menu. I can't get it to work in FH MX, it always re-sets to 0.25 Pt

[JETalmage]

...a hairline on one device may very well be a different stroke weight than a hairline on another device.

Hairlines look great on a laser printer as the "thin" weight for tech drawings and many other things. No hassle to use and reads very well as "accurate" detail.

Been a while since I was in FreeHand. Do I recall incorrectly that a hairline in that program is .25 points?

FreeHand's stroke weight has a specific Hairline selection. FreeHand also, by the way, lets you define in general prefs whatever stroke weights you want to populate the popup menu.

JET

[Guest]

I promise to stop this rattling on after one more question: What IS the stroke weight of FreeHand's Hairline stroke? Is it 0 (zero)? Or is it only an instruction to the output device to lay down the thinnest stroke it can, whatever that may be?

[Monika Gause]

Actually it should be the latter. But as I said before: I didn't manage to apply the hairline in my current installation of FH MX.

[Kurt Gold]

I think it used to be about 0,09 pt.

[JETalmage]

I don't know why the change was made in FHMX. But...

In FHMX, add zero to the list of stroke weights.

Draw two paths. Set one to hairline. (It changes to .25 pt.) Set the other to zero. Zoom to maximum (256x).

You'll basically be looking at the difference between FH and AI. The .25 pt. stroke magnifies (as it should). The 0 pt. stroke does not; it always displays as the thinnest rule displayable (i.e.; it acts like Hairline did in previous versions). Print it to whatever local printers you have available. Again, the zero-width setting seems to act as the former Hairline did.

JET

[Kurt Gold]

Just to control if my 0,09 pt assumption is no phantasm, I launched FH 10. In that version the hairline is indeed defined by a stroke weight of 0,09 pt (to be precise: 0,0882 pt).

Well, Doug, after all we now have a rock-solid definition about the true stroke weight of hairlines, right?

[Guest]

Rock solid. Granite. Thanks.

[j9lemmon]

I'm dealing with this same issue in Illustrator CS6.

I find that using Pathfinder outline works to a point. The problem is, the only way I can see the object is to select it; once I deselect it, the object disappears.

But I found that setting the stroke to .001 pt creates a hairline stroke - no matter how much you zoom in, the stroke remains thin.

[j9lemmon]

I'm now using Illustrator 24.1.1 and still finding it difficult to create a hairline stroke.

Here's my issue currently (I posted this under Design & Drawing with no replies):

I switched to a PC running Windows 10 with Illustrator 24.1.1. When I open a file created on my Windows 7 PC using Illustrator 24, the lines are invisible or look extremely faint, and rounded corners show artifacts that look like added vector points that weren't in the original file.I set all stroke sizes to zero, because these are designs for CNC machining. When I open the file on my Win 10 PC, the strokes are .0001 mm in Properties.

On my Windows 7 PC, I could see the strokes, even though the were zero stroke size. If I draw a new object with a stroke size of 0, I cannot see the lines at all when I deselect the Object.

Any ideas? (There's a place on Adobe.com where you can vote to improve this issue, but now I can't find it).

Image attached of the artifacts on rounded corner.

[Ton Frederiks]

What happens if you switch from GPU to CPU Preview?

View > View using CPU

[umututkus]

As Ton Frederiks suggested switching to CPU preview shows proper line. 

I have this very same issue with Hairline in AI, and cant figure it out:

I need that hairline to be able to cut on a laser cutter after engraving.

Here are the steps i have done so far:

e.g:  Say i am producing Plywood Coasters.

1st:  I need to engrave on Plywood

2nd : I need to Cut that engraved piece.

1) if i send a job to laser cutter and Choose 500 DPI for engraving from the laser driver with a 0.001mm RED RGB STROKE than it can be able to cut.

2) If i sent the same job in 250 DPI it will engrave but it won't Cut the Ply wood Instead when job comes to second stage (cutting) it tries to engrave.

In Different Softwares Like CoralDraw etc.. 250 Dpi setting works fine it engraves and cuts..

Have you been able to solve this problem at all ?

[Gernot_Hoffmann]

PostScript doesn't define hairlines. If the stroke is smaller than a device dependent

limit or zero, then the stroked path is drawn by the smallest rasterized(!) line which

the device is able to draw. That's much more than a device pixel. For rasterizers

with raster cells one may get about two lines per raster cell (cell width= 1/Lpi).

Some tests, mainly p.13:

http://www.fho-emden.de/~hoffmann/raster16052003.pdf

Help text from PSAlter (PostScript editor by Quite😞

setlinewidth operator

width setlinewidth -

...

A width of zero is accepted. The effect of this is implementation dependent, and means 'draw the

thinnest possible line'. The use of this is discouraged, because on some devices, such as high-resoution typesetters, single pixel wide lines are effectively invisible.

The last statement is wrong. The thinnest possible line is much thicker than a single pixel.

Best regards --Gernot Hoffmann

[defaultcf8okl0zm3yg]

Wouldn't it be just great if Adobe fixed this.  I guess its simply not possible. 

None of this works for me and I simply can not cut with Adobe and the universal Laser system.  Hopeless, thanks