Preflight and fix large volume pdf's - Books Digital - print

[nikleon71]

Hi , i am searching for a preflight set that anlyzes and fix pdf files that going for digital printing 4 colour Coated and uncoated papers , which one you suggest? do i have to fix manually one? which are the criteria i have to take in account? Acrobat is safe to fix as the pdf's are large volume pages more than 600 pages sometimes i need something very safe to rely on and fix all the minor mistakes.

 

[Dov Isaacs]

And exactly what do you mean by “minor mistakes?”

What problems are you encountering?

In most cases that I have seen, problems with printing have to do with how the PDF files are created in the first place (failure to specify that fonts must be embedded or specification of improper image parameters such as downsampling to low resolution or use of low quality JPEG) or how the content is composed in the layout program (such as InDesign, Illustrator, Quark, etc.). Such problems are not necessarily going to be either found or more importantly corrected by a generic preflight profile. This goes under GIGO – Garbage In, Garbage Out.

 

[nikleon71]

i ment if the file has low resolution - rgb images , very small letters or thin lines, 100% rich black, actually i am searching for a workflow that will ensure me files will be printed without any changes after rip , used to wotk with a Harlequin workflow and i was extremely happy after updating to version 12. thanks for your answer

 

[Dov Isaacs]

RGB images themselves are not necessarily an issue. Modern RIPs/DFEs properly convert ICC color profile-tagged RGB images to whatever the CMYK color space is. Low resolution images (other than images that of necessity are relatively low resolution, such as screen shots) cannot be “fixed” by a preflight profile - although such profiles can find them in your PDF file.

In terms of “very small letters,” fixing text that was laid out using too small of a point size can't be fixed in a preflight profile, only detected. You need to go back to the authoring program to fix that type (pun intended) of problem.

There are some preflight profiles out there to detect and “fatten” lines below a width per your specification. However, depending upon the original artwork, in some cases it is appropriate to let those lines fade away as opposed to artificially fattening them. For example, if one has a vector diagram that has a large number of lines, some very narrow and others more visible, artificially fattening the thin lines may yield output that really looks obnoxious.

Simply stated, there is no magic cure-all preflight profile to magically make all PDF output look good. Many if not most of the issues go back to the design of the content and the parameters used to create the PDF file.

Personally, I apply two techniques to quickly establish whether a PDF file that I receive can be printed reasonably without going back to the creator of same. The first is to open the PDF file in Acrobat Pro on a large (30" or so) high resolution monitor and if that looks OK, secondly I print one copy to a PostScript printer. Yes, this takes a few minutes, but I find that it finds problems more rapidly and successfully than any preflight profile by itself!

 

[nikleon71]

And what if the pdf files is complicated with layer or transparensies, there is no way to print or visula check as the number of pages can exceed 500 some times

 

[Dov Isaacs]

Layers and/or use of transparency are not necessarily problems! If the original content uses transparency, the best practice is to leave the transparency “live” in the PDF file.

The problem is what you are exactly looking for as a “problem” – layers, transparency, etc. are not necessarily a problem if the original content is properly created. Having a preflight profile point out use of transparency or layers by itself tells you absolutely nothing as to whether the job will properly print.

What specific issues do you actually encounter with PDF files and digital printers? What RIP(s), what printers? Do you have a sample (i.e., a PDF file) that exhibits the problems you see?

 

[Tom Peire]

You say “Acrobat is safe to fix”, then why would Acrobat not be sufficient and what additional functionality is it you’re looking for? Automated/batch processing for large amount of files? As Dov indicated traditional preflight/artwork processing have no fix for low resolution images, but there are AI-based image up scaling technologies available these days.

 

[Dov Isaacs]

With regards to “low resolution images,” one must be very careful in terms of what one does for “low resolution images.”

(1) Some “low resolution images” such as screen shots are inherently low resolution. They match the resolution of the screen from which they are taken. Attempts to “uprez” such images may yield a real visual mess with ugly artifacts, not something that is inherently higher quality.

(2) Having used tools in Photoshop to increase image resolution, it is very clear to me that there is no single setting that is correct for all images (and of course, not all images with resolution below some “magic” value, such as 300dpi should have artificial image resolution enhancement). As such, each image that might be a candidate for such treatment needs to be examined individually with settings appropriate to the particular image and its contents!

(3) Given (1) and (2) above, my original recommendation in terms of visually reviewing the entire PDF file on a large, high resolution, color-calibrated monitor (Windows or Mac, it doesn't matter ) and producing a single laser printer copy (PostScript printer) still stands.

 

[chriscozi]

(3) Given (1) and (2) above, my original recommendation in terms of visually reviewing the entire PDF file on a large, high resolution, color-calibrated monitor (Windows or Mac, it doesn't matter ) and producing a single laser printer copy (PostScript printer) still stands.

And I will 'assume' the cost consequences defeat the original poster's business model.
Someday - maybe sooner than we think - it will all fix itself and we won't need those pesky print shops any more.

 

[Dov Isaacs]

This whole thread reminds me of a phone call I received over 15 years ago from a well-known writer in the print industry press. She wanted to know the technique I recommended for proper “sharpening” of images for print.

My response — “properly focus the camera!”

 

[nikleon71]

THis i Preflight sample of a pdf with 496 pages, almost everything red, the print os might pass. I was asking if you know anything about a pdf rip solution that deals extremely well with this kind of problems to create datalock files before i impose it and print it.

 

[Dov Isaacs]

Some observations:

(1) The preflight profile you are using is for testing the validity of PDF/X-1a files. Unless you specified that your client provide you with a PDF/X-1a file, this profile is not of much help.

(2) Unless you are using a RIP/DFE that is over 15 years old, PDF/X-1a is really an obsolete standard and workflow based on PDF 1.3 with no ICC color management, no support for anything other than device dependent CMYK plus spot colors, no support for live transparency, etc. Reliable 21st century PDF print publishing workflows should be using PDF/X-4 (based on PDF 1.6) providing support for live transparency and ICC color management (especially ICC-color managed RGB).

(3) The diagnostics under Page Description Errors (errors in PDF syntax, missing extended graphic state, and missing XObjects) are exceptionally problematic. What application and workflow produced this PDF file in the first place? This is certainly not PDF directly out of any standard layout or graphic arts program.

What you presented is clearly more than an issue of finding and using “a preflight set that analyzes and fix pdf files that going for digital printing” – the page description errors noted above cannot be readily “fixed” by simply applying a preflight profile.