ID Preflight captures an obscure Illustrator error
I’m not saying this is wrong, but InDesign’s new Preflight feature works a little more advanced than I thought it would.
I have an ID document with the Preflight setting for images to reject any color images with resolution under 250 ppi.
I placed an Illustrator file with a glow into the ID file. Now glows automatically create rasters. So I made sure the Document Effects Raster setting in Illustrator was set to 300 ppi.
When I placed the file in InDesign I scaled it up a bit. Now, I’ve been scaling vector files for over 21 years! Never had a problem! After all, vector files are resolution independent.
So I was surprised when InDesign’s Preflight panel reported that the Illustrator file had too low a resolution. That didn’t make sense.
And indeed, the Links panel info did not show any wrong resolution at all because InDesign’s Links panel doesn’t show resolution for PDF files which is what the Illustrator document is as far as ID is concerned.
Fortunately, I knew about the glow effect. So I opened the Illustrator file and scaled it up to about the same size as it appeared in the ID file.
Then I updated the Illustrator link.
Preflight deleted the error.
It’s an obscure situation, but could cause confusion.
Illustrator doesn’t resample the raster effect when it is scaled up in the ID file. Rather, the raster effect is scaled to create an effective ppi that is lower than the raster effect setting in Illustrator.
So you have to make sure that Illustrator images with glows and other raster effects (shadows, feathers, etc.) aren’t scaled up in ID to create a low resolution effect.
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Makes sense to me
Well, sure. It makes sense after I figured it out!
;-)
That’s why we love Live Preflight in CS4.
Thanks for the great post Sandee!
It’s very sensible of the ID Preflight to warn us about this scenario.
Still, I want to default-disable the Preflight, and only turn it on now and then — it sucks up some CPU cycles needlessly, when running, which is unnecessary for 95% of my ID working time. It even checks when I create a new, blank document! But I cannot find a way to make the disabled setting stick — I can only turn it off on a particular document, but when I reopen it the damn thing is checking up on me again. Does anyone know how to change this Preflight default to off?
Thanks for highlighting this Sandee.
There is also a setting for detecting
“Overprinting Applied to White or [Paper] Colour”
which is something I have come across occasionally.
I have never conclusively worked out where this can come from as I cannot apply Overprinting object coloured White or [Paper] is InDesign itself.
I suspect it could have come from artwork cut ‘n’ pasted from Illustrator? I don’t know Illustrator so am only guessing.
Before Live Preflight I could only spot this using Overprint Preview Mode.
Simon.
> I suspect it could have come from artwork cut ?n? pasted from Illustrator? I don?t know Illustrator so am only guessing.
I think you’re right about this.
Illustrator does make it easier to create the overprint white situation.
Q. Re: Does anyone know how to change this Preflight default to off?
A. With no documents open, open the Preflight panel and make sure that “On” is not checked.
In Illustrator, when you try to set a white object to overprint, you get a warning telling you that this is not a wise thing to do. But when you change the color of an existing object from black (with overprint) to white, Illustrator remains silent. I think it’s the main reason for having overprinting white.
Sandee bring an important fact about Illustrator, even if the portion of the illustrator document is a compatible PDF and contain live transparency, the raster parts inside of it is already “Apply” inside that portion of the PDF and it is at the Document Raster Effect Setting in illustrator. So don’t expect to be able to scale it as much as you want. Glad, ID Preflight is able to catch that error peoples too often make.
Thanks, James! I knew of course about the usual no-docs-open-to-set-defaults procedure, but when no doc was open I thought I couldn’t get hold of the Preflight palette, as I was accustomed to entering it via the little icon below on the doc window. My stupid bad, for it lives in Menu: Output — not an entirely illogical place, I must admit. So, thanks! :-)
Sandee,
You could also increase the Document Effects Raster setting to a higher ppi without having to change the size of the artwork.
Brian,
Nice idea.
A resolution of 600 ppi makes it easier to insure that a slight scaling wouldn’t show up as a problem.
But if I had to scale a humongous amount in ID, I would just go back into Illustrator to scale up the file.
Fortunately the resolution of the rasters there is live and is constant no matter what the scaling.
At first thought, changing the resolution of raster effects in Illustrator may sound like a good idea, but there are two problems with that approach:
1. When done to existing files, it could change the look of currently applied effects (such as blur) and make them smaller and less noticeable.
2. It will take considerably longer to render those effects, making your work in Illustrator slower.
I think it’s best to leave it at 300ppi (it takes long enough to render at that resolution!), and just make sure you’re working at the correct size.
Dan brings up some very good points.
OK, now I think it’s better to not increase the resolution.
But I don’t think I’m wishy-washy.
Actually maybe I am. No I’m not.
Well I am.
No. Yes. No. Yes.
Sandee, this is a great post.
As mentioned, increasing the resolution in Illustrator is a bad idea because it will change the appearance of any effects that are already applied. And if you think about it, that’s why this “issue” occurs in the first place.
When you place a native .AI file into InDesign, ID is reading the embedded PDF 1.5 file. Granted, this PDF file is unflattened, so transparency is still live, but PDF can’t understand the live “complex appearance” structures that Illustrator creates. As such, what is contained in the PDF file is exactly the same as if you had selected all your art in Illustrator and used the Object > Expand Appearance command. In other words, live effects are expanded in the PDF file.
This is desirable, considering the alternative. Say you apply a small drop shadow in AI, and then place that art into ID. Then you enlarge the art 1000% — wouldn’t you expect the drop shadow to scale along with the art? If the drop shadow were indeed a live effect, the drop shadow would remain small while the art would be enlarged. It’s akin to scaling art with Scale Strokes and Effects turned OFF in Illustrator.
On a whole different level, it would also mean InDesign would need to have access to all the Illustrator effects and their individual settings.
:) Mordy
@Mordy – I think allowing InDesign to have access to Illustrator effects would be a great feature request.
Q: I have never conclusively worked out where this can come from as I cannot apply Overprinting object coloured White or [Paper] is InDesign itself.
A: If red text is overprinting via Paragraph Style and you change the text color to Paper in the style, it is still overprinting, although the dialogues does not show it. ? (Compare: If red fill of object is overprinting via Object Style and you change to Paper in the style, the dialogue still says “Overprinting” although Paper does not overprint in THIS situation.)
Old bugs in CS3, not fixed in CS4.
Hi All,
This is a typical question of compatibility of various softwares.
I exported a colored flash artwok to eps, did some redrawing in Illustrator, as flash cannot export gradients, transparency, and flash effects in eps.
I converted this colored artwork in grayscale using convert to grayscale filter in Illustrator.
And finally this eps file is placed in InDesign for composing a grayscale single color document.
The problem is during preflight in color seperation the artwork still shows four color image in the ojects containing tranparency.
Any advice to export a perfect grayscale pdf for single color printing (black and white)?