Printing black separations

[brianr17527289]

We're trying to wrap our heads around an oddity we've been hit with in Adobe Pro X. We use InDesign to create newspaper pages, then export as pdfs, which are transferred via folder to our printing site.

I admit up front I don't know what's under the hood, but suffice it to say it works - our pages have separated properly day in and day out as far as we know, until a recent episode. A page was handled exactly as all the others. Looking at the print preview, the four-color page had all four inks nicely represented - including the black for four color photos and considerable text.

However, the pressroom says the photos arrived there with no black. The copy was there, but the black portion of the photos - which can be seen clearly in print preview - didn't make it through the system.

Without inviting ridicule, we wonder if anyone can explain how we made this happen. It didn't happen before (using this process). It hasn't happened in the week since, despite dozens of pages and many photos. Can anyone reproduce this (without manually killing off the black printer)? It would seem to us that if the black type and the black printer appear in the print preview, they would remain through the platemaking process.

Thanks.

[Dov Isaacs]

Don't worry. There is no reason to ridicule you (or anyone else) for posing a legitimate question.

Quite frankly, without seeing the file you sent to the printer, it would be virtually impossible for us to even guess what is going on here. If you used the Output Preview / Separations Preview in Acrobat Pro and you can see content in each of the separations, that should also occur when your printer is processing the file. If you haven't checked in Acrobat Pro with the Output Preview / Separations Preview, do so and confirm that there is black in the images.

You might also want to check with your “pressroom” to determine exactly what they are doing with your PDF files once you provide the files to them.

          - Dov

[brianr17527289]

Thanks for getting back to me.

The page in question did indeed have black in each separation when viewed in the separations preview in Acrobat Pro.

Apparently this situation has occurred intermittently in the past, and to our knowledge, always on this page.

Some background:

• We are a daily newspaper operation, using InDesign 6 to create our pages. We export them as pdfs, then use a shared folder to transfer them to prepress.

• There, the pdfs are run through a platemaking process using Agfa equipment and programs.

• The page in question is an early run - all pages are produced by the same editors, but this page is handled by prepress at a different time from the rest of the paper.

• This page doesn't have the "no K" problem every week - again, it's intermittent.

• We are urged to use an in-house autotuning program for our photos, but those of us with Photoshop experience use it instead (the autotuning can create problems with a photo that isn't already rather good).

• It has been suggested that the issue is caused by using Photoshop - the editor who works up that page uses Photoshop. However, he uses Photoshop for his color photos on other pages, and I use the program nightly, with from six to 12 photos on the page. To my knowledge, we've never had an issue with the black not appearing in these photos.

If, indeed, a pdf with images worked in Photoshop is somehow different from a pdf with images worked in another program, then we will address that by working the photos twice - once in photoshop to correct visual issues, then in the autotuning program to address the settings that can confuse Acrobat Pro.

Thanks again.

[Test Screen Name]

My advice: when the problem hits, SAVE THAT PDF. Now finish the press panic and when you are ready, try that page into the same workflow. Does it RELIABLY produce no black plate? Ok, if so, you have a solid test file. Check it out with the Separation Preview (NOT just a print preview). Do you see it there? Ok, raise a case with Agfa, as their equipment/software is separating.

[brianr17527289]

Thanks to all.

It turns out the page editor didn't convert the photos on that page from RGB. Apparently that leaves something in the file that, despite the fact black shows up in the preview, prevents that black from surviving the platemaking process.

[Dov Isaacs]

Something is very, very wrong. Modern PDF workflows are designed to allow ICC profile tagged, color managed RGB images in the PDF as well as live transparency. Conversion of the images to DeviceCMYK as well as all transparency blending should occur at the RIP, not earlier. Any Agfa RIP software from within the last eight to ten years should be able to handle this with no problem whatsoever.

          - Dov