A PDF of a PDF - cause poor print results?

Discuss QuarkXPress print functionality and printing workflows
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Glenn McDowall
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A PDF of a PDF - cause poor print results?

Post by Glenn McDowall » 10 Mar 2006, 05:05

Hi easternherp
I suspect you have pitstop since you have apogee, does that outlined text have a smoothness in the prepress inspector. Or if you run a Pitstop profile check does it detect a flatness above 0.02 in the 'line art' check.
I often see this effect through our Delta Rip when an early Illustrator eps is re-saved as Illus 10 or above then output separated out of quark, I then have to set the document resolution in Illy to 2400dpi to resolve OR going composite ps and distill to pdf has sorted it too (which is the opposite of your problem?!).

a.hayton
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Joined: 31 Dec 1969, 19:00

A PDF of a PDF - cause poor print results?

Post by a.hayton » 10 Mar 2006, 05:28

Hi Glenn,

I can't remember what it was set to, but I do remember that I could print it to our laser printer and it was ok, my colleague could not print it correctly to the same printer using the same print settings and version of Acrobat. In the end the customer was asked not to convert to outlines and we haven't had a problem since.

Anonymous

A PDF of a PDF - cause poor print results?

Post by Anonymous » 10 Mar 2006, 15:47

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Hi Glenn,

whether text gets converted into a bitmap or into a outline in Adobe apps is not a question of object stacking but only of the flattening style used.
By changing the stacking order you can prevent that text is being flattened at all (if it's in the foreground in respect to the foremost transparent page object).

Within a Adobe flattening style you find a slider which allows to decide whether the flattening should be done preferably on a bitmap or vector level. This slider has to be set to the extreme right (which means pure vector based flattening). Even if a vector based flatting happens which converts text into clipping path (or during native PDF export into text in rendering mode 7), the hinting information of professional fonts is lost and the PDF renderer and PostScript interpreter loose their ability to use its special algorithms to smoothen the text rendering.
By loosing the hinting information the glyph outlines can vary up to one device pixel from the "perfect" shape. Therefore its clear that it is much more obvious on screen (which is 72 to 96 dpi) or a low resolution desktop printer (600 dpi) than on an image setter RIP which is typically run with 2400 or 2540 dpi.

Anonymous

A PDF of a PDF - cause poor print results?

Post by Anonymous » 10 Mar 2006, 16:05

[strong]Glenn McDowall:[/strong]... does that outlined text have a smoothness in the prepress inspector. Or if you run a Pitstop profile check does it detect a flatness above 0.02 in the 'line art' check.

Hi Glenn,

don't mix up smoothness and flatness. These are two totally different entities.
Smoothness controls the quality of the rendering of smooth shadings (PostScript 3 blends). Flatness controls the rendering quality of bezier curves.
A good value for smoothness is 0.005 which means a 0.05% tolerance in each color channel involved. A good value for flatness is 1.0 which means the maximum deviation during curve rendering is one device pixel.
So for the converted to vector outlines only the flatness value is important.

[quote:5f9d381d30]I often see this effect through our Delta Rip when an early Illustrator eps is re-saved as Illus 10 or above then output separated out of quark, I then have to set the document resolution in Illy to 2400dpi to resolve OR going composite ps and distill to pdf has sorted it too (which is the opposite of your problem?!).

Acrobat Distiller 7 offers a hidden new feature which allows to ignore the (wrong) flatness value defines by the PostScript code. This way it can be substituted by the output device which always uses an ideal value of 1.0 as long as no other value is defined.
It's controlled by the "/PreserveFlatness false" key/value pair within the joboptions.

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Glenn McDowall
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A PDF of a PDF - cause poor print results?

Post by Glenn McDowall » 13 Mar 2006, 04:19

Hi Robert
Many thanks for your detailed explanations, the loss of hints makes perfect sense.

As you thought I muddled smoothness with flatness. There doesn't seem to be a way of detecting flatness in the Pitstop Inspector Panel, I saw the smoothness and assumed wrong.

You state a flatness of 1.0 is ideal for a platesetter, I wonder why Heidelberg recommended 0.02 (this is where I got my figure from) which would be overkill by a factor of 50.

In all my cases of the "O to polygon" I would have been using Distiller5 or 6 to resolve, I'm guessing this is Quark being unable to separate later Illustrator EPS (v10 and above) as well as earlier (v8 and below) EPS.

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Glenn McDowall
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A PDF of a PDF - cause poor print results?

Post by Glenn McDowall » 16 Mar 2006, 09:36

Hi easternherp, just seen another case of "O to polygon", really rough polygons too. I was sent an advert set in photoshop(.psd) with type layers drop shadow etc etc, normally this gets saved as a copy as EPS and quark and distiller keep the text sharp. Well this one had to go into IDCS2 so I placed the native psd but the text became rastered in the exported pdf. The solution (thanks to Jim Oblak for this) was to save the photoshop as a photohop.pdf and place that into ID. In the mean time I had tried converting the Type layers to Vector in photoshop and saving as pdf, opening this in Acrobat is where I'm seeing the polygon type, the vectors look Ok but the display is polygon. Weird.

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