Why does printer need a flattened file when there is no transparency?

[anneroku]

I sent a pdf of an AI file to a digital printer to preview before sending out to print.  In the email I received from the printer, I was told that this pdf was "transparent (meaning more than one layer) and needed to be flattened." (Quotes are taken directly from the email.)

I am puzzled about this because there was no transparency anywhere in the original file.  Yes, the original AI file had three layers, but it was all flat, solid vector artwork, no transparency or transparency effects anywhere.  Nothing that normally needs to be flattened.  It will all be printed CMYK, and my understanding is that the printer will eventually convert the whole thing to a .tif file.

I am awaiting a response from the printer and have read all I can about flattening to see if I am missing something.  In the meantime, can someone tell me if this is a common request from digital printers?  Am I missing some important concept regarding flattening?  Thanks!

[_scott_]

PDF 1.4 (Acrobat version 5) or greater supports layers. This is probably what needs flattened. FLattening does not automatically mean there is transparency. The flattening could simply refer to the layers.

Save your PDF as PDF1.3 (Acrobat 4) and it will be flattened upon saving. You might even consider using PDFX-1a which is a press-ready flattened PDF format.

[anneroku]

OK, this makes sense.  So the printer wants no layers.

[anneroku]

Is it best to put everything on one layer before creating a pdf for print?  And do most printers prefer a flattened pdf format?

[rmgman]

I've been in Prepress for over 15 years and this is the first time I heard that requested by a printer. What's this printer's name: Ben Franklin?

[anneroku]

Thank you for saying this.  I thought it was a weird request, myself.

This is an online digital print shop and I have seen printed work that they produced and the quality was excellent.  However, this printer also strongly recommended creating outlines for all text type, which I also thought was strange.  I am not that experienced with digital printing and I have no idea if this is standard practice.

[rmgman]

Converting all the text to outlines is a standard practice, since it saves the trouble of having to send fonts with your job and also prevents any font embedding issues. (since there are no fonts to embed) The con to that is if there are any last minute type corrections, you would have to submit a new file with you making the correction instead of being done on press.

[anneroku]

Thanks, this is a good explanation of the pros and cons.  I have read several discussions in the Adobe forums about outlining text and am still not sure how standard a practice it is.  For this job, it's not problem since it's small.  I don't routinely outline type and have never had a problem, and I am under the impression it is not a good idea for longer projects with lots of text.

[anneroku]

If the printer wants no layers, what if I just manually move everything to a single layer?  Would this give a different result than flattening (for a file that has no transparency)?

[_scott_]

I agree that it is an odd request. It can only becuase they are working with really old equipment or have no clue what they are doing.

Simply Save As in Illustrator, choose Adobe PDF, then Choose PDFX-1a from the Job Options drop down. You'll get a flat PDF. There's no need to change the art in any way.

Supplying PDFs this way means you don't need to outline text or do anything special to the art. It's all taken care of when Illustrator saves the PDFx1a file. The fonts are embedded and will look better than if they are outlined due to font hinting which is present in live type, but not in outlined type. I haven't outlined type in years unless some odd duck asks for an EPS.

[anneroku]

I can't choose PDFX-1a because they have also instructed me to select the following when I create the pdf:

under Output> Color Conversion> No Conversion, which is not an option with that preset.  (I'm working in CS3.)

However, it looks like I could use PDF1.3 (Acrobat 4) as you suggested above, along with Standard: None.

I personally prefer not to outline text and am wondering if flattening in this way can be substituted for outlining.  The printer seems to be mostly concerned about accidental font substitution.  I am not worried because I know they printed something using the same fonts last year without outlining or flattening, and it was fine.

But setting aside the type issue, I am still curious if manually moving everything to one layer would achieve the same result as flattening in a file with no transparency.  Would flattening do something other than simply moving all items to one layer?

[_scott_]

No. Moving all art to one layer in Illustrator will not flatten the artwork. Illustrator always has a transparent layer (no background).

Use PDFX-3 if they are asking for no color conversion (although simply asking for that tells me they aren't running a color managed workflow).

[anneroku]

Thanks, that's helpful.

I still don't understand what flattening non-transparent artwork actually does to it, though.  I generally understand what is going on when transparency is flattened, but how does flattening affect non-transparent art?  Is the only difference then that the transparent layer you mentioned disappears?  (And where exactly is that transparent "no background" layer?)

[_scott_ · Accepted solution]

All Illustrator files have no background - EPS - AI - PDF.

When you place them into Indesign or Photoshop do you see a white background?

No. That's because there is always a hidden layer of transparency.

You can't see or edit this transparency layer, it's simply there.

When you flatten artwork in say a PDF, the application it adds a white background assuming white is the color of the stock it will be printed on. Traditional mechanicals were all done on white paste-up boards because copy cameras don't see white. The same theory is used in software today - white = transparent or not seen.

[anneroku]

Thank you -- I think you have identified exactly what the printer meant in reference to transparency in my pdf.  I was unaware of this hidden layer of transparency and your explanation has helped clarify the issue for me.  I had assumed the printer was referring to transparency in the artwork.  But you are right -- the reference was to that transparent layer in the background.

While this was an unusual request from the printer, I'm now wondering what other printers do about this.  Do most RIPs not require flattening?  Or do most printers just handle it themselves when they receive a pdf from a client?  Can the printer do the flattening themselves if they only have a pdf from an un-flattened file?

[_scott_]

I've been doing this for quite some time and in the past 5 - 7 years I've only supplied PDFX-1a files to printer providers ranging from huge multi-state printers to small local shops. In fact, an eyebrow is piqued anymore if any printer I'm unfamiliar with asks for anything different.

A good print shop should never need anything more than a solid PDFx1a file. They may have some specific request such as trim marks or no trim marks, single pages or spreads, but the PDFx1a has always been good. As I posted earlier, these are flat, press-ready, files. So there's little worry about changes after the printer has received the PDF. And PDFx1a files make the printer's job easier because they don't have to worry as much about errors occurring in prepress.

The only time I hear of other file formats being requested or native file requests is when working with small mom and pop print shops. Sometimes these providers can't afford or don't need the Postscript Level 3 RIP for their clientele so they'll ask for native files. Usually native files for applications 2 or 3 versions old.

It's all sort of relative depending upon the size of the print job and the corporate size of the print provider.

I've never heard of anyone asking for an un-color managed PDF though. That doesn't mean there's a valid reason for it.... just never heard of it here.

[rmgman]

I agree with all that Scott says.

What makes it confusing for people just learning to use Adobe software and digital printing is that within Illustrator they have "Flatten Transparency" and also "Flatten Artwork". You would think this means the same thing, so not so. The first applies to "Transparent" styled art and the second applies to "Layers" in the layers palette. (Which further doesn't make sense since each layer has a sub-layer and in fact each object within a layer has a stacking order. Sheesh!)

As far as converting all fonts to paths, I've seen even some larger shops request this. In most cases, this is a decree made by some supervisor after pulling the hair out of his head about font problems encountered in the prepress area: "For now on folks, ALL fonts need to be paths! Or yer fired!"

[anneroku]

Thanks for clarifying these two flattening commands -- I wasn't sure what the difference was.  I was originally assuming the printer wanted me to "Flatten Transparency" and was confused because there was nothing to flatten in the art itself.  I see now that I needed to flatten the layers.  Seems like that command should be "Flatten Layers" rather than "Flatten Artwork."

You bring up a good point about the stacking order and sub-layers, which still remain even after flattening.  Why does that not present a problem or need further flattening?

[rmgman]

Beats me. Like I said earlier in this thread, I've never heard of this "flattening" the layers into one illustrator layer. Sounds like your printer just wants to make things as bare bones as possible to avoid any problems and issues down the road. He must be using some very old software and equipment.

[anneroku]

I've never had another printer request this flattening.

But now I'm wondering, when is the "Flatten Artwork" command normally used?  For what reasons would you need to flatten the layers?

[_scott_]

You'd use it if you wanted to reduce all layers to a single layer. Basically, it's more a "merge Layers" command than a "Flatten" command. The terminology within Illustrator is terribly misleading.

[anneroku]

Is that helpful just for organizing a complicated illustration into fewer layers, or is there another technical reason or benefit to merging layers?

Does the "Flatten Layers" command also eliminate the invisible transparent background, or is it not truly "flattening"?

[_scott_]

Nothing within Illustrator will remove the invisible transparent layer. It's only removed upon export, printing, or saving to some formats.

Honestly, I've never used the Flatten Artwork, or Flatten Layers commands. There's never been a reason to. But.. if I were to use it, the only reason would be to make future editing of a file as difficult as possible. I.E. Flatten layers, select all, pathfinder merge, save as eps.

[anneroku]

OK.  Thanks for explaining.

[_scott_]

ScottWeichert wrote:

Nothing within Illustrator will remove the invisible transparent layer. It's only removed upon export, printing, or saving to some formats.

I should ammend that a bit.....

Using raster effects such as glows or drop shadows will place a white background in the file that will not be seen unless you turn on the Transparency Grid under the View menu. Depending on artwork... This could have the appearance of removing the transparent layer.