Verifying profiles in a PDF

[smeyyappan]

I wanted to know what profiles have been used in pictures ina PDF document. I tried to create an Indesign document with various pictures, each with a different profile and rendering intent (by using "convert to profile" command in photoshop). The Indesign document was postscripted using Adobe PDF 9.0 ppd with the option "Let Postscript Printer determine colors option".

I distilled using Distiller 9.0 with "High Quality Print", "PDF-X/1a:2001" and "Press Quality".

In all those PDFs I am unable to identify the profiles. I tried using following methods.

1. Pitstop Pro - when I select any picture I placed, it shows "None" for Profile.
2. Advanced -> Preflight using Newspaper ADs or PDF-X, says output intents missing or US Web uncoated v2.
3. Click a picture using Object tool and right click and "Edit Image" opens the image in photoshop. It shows as untagged 8bpc (in the status bar).

Can anyone with some experience calrify, how one can verify if right profiles are used in pictures coming in a PDF print document? We are printers and we need to be sure of right profiles are used.

With Best Regards
Mey

 

[Lukas Engqvist]

None of those methods support profies. Distiller or rather postscript, does not support Profiles you can let printer determine, if all RGB have same profile and you tell the distiller what RGB profile you are expecting. PDFx4 is the proper version for profile handling (PDF x3 supports profiles, but not transparency wih means a very dangerous combination).

PDF x1 a is for a workflow where all colour is device CMYK wich device is tagged in the output intent.

You should look at the whole of your flow.
Important is that first set colour settings and the transparency blend space in InDesign: then you must have a joboptions that either converts to the correct CMYK (preserving numbers if you want no CMYK CMYK conversion), or embedds source profiles for the RIP to handle conversions.

There are whole books on the subject so giving an extensive answer in one post is just not realistic. There are some threads pointing to what litterature is a good base for colour management.

 

[smeyyappan]

Dear Lukas,

Thanks for the reply. But in actual scenario, the client is sending the PDF to us, the printers. They are embedding the right profiles in their pictures and then they are taking to the layout application.

But I need to make sure that they have used the right profile in their pictures. Is there a way I can check a PDF file and find out what profile was used in a picture?

Hope I made it clear.

Thanks again.

With Best Regards
Meyyappan S

 

[Magnus]

If you advice your clients to use any of the PDF/X-standards (mentioned by Lukas) when they make their PDF's you can easily check if they converted the images to the correct profile. In Acrobat Pro or similar.

There are plenty of ways to make a PDF in which icc-profiles aren't embedded, and then there is no accurate way of estimate which profile was used for conversion.

If your CMYK profile has a low TAC then you can set up a preflight (Pitstop or Acrobat Pro) to check for overriding ink coverage, then assume/guess that the images are converted to the correct profile..

..but PDF/X is really the way to go.

 

[Lukas Engqvist]

I will try and be more explicit. Embedding all profiles can give you more problems than you want.
My advice is still to stick with a "safe CMYK" (preserver numbers for CMYK) strategy.

If you go PDF-X1 you can not see if client converted colours using correct RI or if client used correct source profile. What you will be sure of is that the PDFx1 has enough information to be output consistently irrespective of brand of rip, proofer. On screen it will also view correct. All colours on analysis will read Device CMYK, but you will also through the Output Intent know what Device is meant. Are the CMYK values intended for coated, uncoated or News paper. In the layout application you will have to have the correct colour management settings, and the document CMYK profile and working space Profile should be the same as intended output. With this you will find you can trust readings of separations in layout, and Acrobat. They will be consistent, not flexible but safe. (Note spot colours are allowed, but you will do best to keep spot colours as spot colours only if you intend o print them as such, otherwise you will need a very up to date RIP that can handle overprin emulation of spotcolours and transparency)

PDFx-4 can be treated as PDFx1, where all colours are converted to device CMYK = output intent. You do have advantage of live transparency, wich means you hava a higher level of abstraction = there is more you can do with the touchup. Flattening has not happened.
In PDFx4 you also can choose to not convert to CMYK. This means that wich in the layout is Device CMYK will be device CMYK, but you can also have Source profiles. Images that do not have source profiles will in inDesign have the document RGB or Device CMYK profiles. You will get most consistent results if you use CMYK as transparency flattening space.

There is an option to "include all profiles" this will include all profiles wich is more information, but you will not know what your client had configured. This option I do not recommend since it will most likeley invoke CMYK to CMYK conversions meaning text and hairlines may be converted from pure black. (I am not sure how rendering intents are handled) As far as i understand any untagged objects will inherit the document profiles of the layout document.

Also remember that a customer who converts to the correct CMYK profie can spoil an image by "tweaking" the curves so that they have the right profile, but the wrong TAC. (Oh how i wish there would be a function in Photoshop that constrained curves to honour TAC in the profile.)

 

[mattbeals]

Not to be too redundant but once you go through PostScript you're screwed. Now having said that... There is one vendor that I know of, no I won't mention who, who is working on "reverse engineering" the CMYK separations in order to come up with a reasonable estimate of which profile generated the separation. That doesn't mean that they can tell if BPC was on, it was ECI RGBv2 vs. sRGB, etc. Unless you connect to the users desktop to examine their color settings you are not going to be able to tell what they are doing or did. With the exception of PDF/X-1a or PDF/X-4 and the embedding of an output intent.

Best advice, move to a PDF/X-1a:2003 or PDF/X-4:2008 workflow starting at your customers desktop. Then you'll have some idea of what it going on.

 

[Magnus]

..dont know if anyone did anyone mention that you should go with PDF/X ?

 

[smeyyappan]

Thank you Lukas, Mattbeals and Magnus.

I am getting to understand the complexities involved.

We should advise PDF-X standards for our clients, which we have been contemplating since some time.

Thank you all once again.

With Best Regards
Mey