PDF & CMYK

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Level 4

1,374 points

PDF & CMYK

I'm preparing a booklet for a charitable cause that needs to go to a commercial printer due to the number of copies required. The printer that I'm considering using is quite prescriptive about the file format that they require. This is an extract from their specification:

Pdf – format
When creating a pdf please ensure that you observe the “Borders and Bleeds” section above and make sure you embed all the fonts. Any photos or graphics should be embedded without compression and MUST be in CMYK . The pdf MUST be in a CMYK format.
Jpeg – format
When creating a jpeg please ensure that you observe the “Borders and Bleeds” section above and make sure you save in the highest quality option. Any photos or graphics should be embedded without compression and MUST be in CMYK. The Jpeg MUST be in a CMYK format.

1. I understand what RGB and CMYK are but how do I know what format the photos and graphics in my document are in? Some of them are shapes created with Pages. Some are JPEG photos from my camera and some are pdfs of artwork from sponsors. There doesn’t seem to be any info available in Pages, iPhoto or in the Finder. I’ve even downloaded an EXIF tool but it doesn’t tell me if the photos are in RGB or CMYK format.

2. I’d planned to save the document as a PDF/X file. Does this somehow automatically ensure that my graphics and photos are CMYK? I looked at the Color Sync Destination Profile and it says Generic CMYK.

3. How can I guarantee that my pdf and the embedded graphics/photos are in CMYK? I realise that if this were a professional publication then one would go to great lengths to ensure the colours were right. For this document though, near enough is OK.

I've read a number of threads on CMYK and RGB conversion here. None seemed to reach a suitable conclusion for me.

Please don’t tell me to use Photoshop or InDesign. I can’t justify the cost of those applications.

iMac 17" Flat Panel (OS X 10.4.8)

Posted on Mar 21, 2007 4:12 AM

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Answer 1

IanB Author

Level 4

1,374 points

Mar 21, 2007 4:32 AM in response to IanB

I think I've just answered my first question as far as the photos and pdfs are concerned. I downloaded GraphicConverter and it seems to access extra information about my files. They are all '(RGB, 32 bit)'.

How would I get at that information via the standard Apple software?

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Answer 2

Tulse

Level 5

5,806 points

Mar 21, 2007 6:50 AM in response to IanB

If you Get Info on the file (in the Finder, under the File menu), the "More Info" section of the panel should tell you the colourspace. You can also open an image in Preview and in the Tools menu use Get Info to obtain fairly detailed file format information, including colourspace.

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Answer 3

IanB Author

Level 4

1,374 points

Mar 21, 2007 7:09 AM in response to Tulse

Tulse

I don't get the information in the Finder but I do in Preview. I didn't know about the latter so thank you very much!

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Answer 4

Mar 21, 2007 8:57 AM in response to IanB

Properly converting from RGB to CMYK is a very complex process; it's not like, say, going from sRGB to Adobe RGB. You should talk to the printer about having them do the conversion for you, for several reasons.

CMYK has a different gamut (range of available color) than RGB, and if you just randomly say 'become CMYK" to an image, the colors will probably look flat and distorted. In order to properly create a CMYK image, you need to know about things like the ink that will be used, the paper on which the file will be printed, etc. in order to correctly proof what the final output will look like. Usually images need a fair amount of tweaking in the conversion process.

If the printer will do it for a non-outrageous fee, it is easier and more likely to produce good results to let them do it, unless you are very sure of what you are doing. If you decide to do this yourself, it is very critical that you get a proof sheet from the printer before the run is made.

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Answer 5

Tulse

Level 5

5,806 points

Mar 21, 2007 9:08 AM in response to Barbara Brundage

it is very critical that you get a proof sheet from the printer before the run is made.

Which is always good advice on any significant print job.

IanB, when you say you don't get the information in the Finder, do you mean that the Get Info panel doesn't have a "More Information" section, or that this section does not provide colourspace info? (This could be a difference in our systems -- I'm using 10.4.8, and it looks like you've got 10.4.7.)

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Answer 6

IanB Author

Level 4

1,374 points

Mar 21, 2007 9:13 AM in response to Tulse

Tulse

Actually I'm using 10.4.9 (thanks for reminding me to update my Public Profile).

There is a More Information section but it provides no colorspace information.

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Answer 7

Mar 21, 2007 9:33 AM in response to IanB

FWIW, I just checked the file for a brochure I did in Pages, both as a Pages file and a PDF-X and I don't have any colorspace info in Get Info for the total file, either. (Don't really see how you could.)

However, when opened in PS, the PDF-X is rasterized as a CMYK file.

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Answer 8

IanB Author

Level 4

1,374 points

Mar 21, 2007 9:37 AM in response to Barbara Brundage

Hi Barbara

Thank you for responding. I've no doubt that doing a 'proper' job is very complex. I understand that the CMYK gamut is different to RGB and that the conversion needs to be done with specific paper, ink and print devices in mind. I don't need anything like 100% colour match as this is most definitely an amateur document.

Since I posted my original questions I've done a bit more reading and this document on Colour Management with Mac OS X Tiger in particular.

http://images.apple.com/pro/pdf/ColorMgmtinTiger.pdf

If I understand this document correctly, the whole point of OS X's Colour management features is to make it easy to do what I want (subject to the limitations of gamut on the destination profile). I think all I need is for the printer to give me the colour profile they will use for their output device and I stand a pretty good chance of getting a reasonable match. Did I get it right or is there an additional layer of complexity when you start talking about professional printing machines?

Your advice about getting a proof is very sound and something I definitely intend to do.

Questions 2 and 3 of my original post remain unanswered. If you or anyone else can help me with them I'd be most grateful.

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Answer 9

Mar 21, 2007 9:50 AM in response to IanB

It has been my experience that PDF-X files made by OS X are seen as CMYK files by other programs that can do CMYK, but this is not a given. For instance, Photoshop Elements can import them, although it will not open a regular CMYK image. It sees them as untagged RGB images. Reader shows the file as Untagged.

If you have access to a computer with a recent version of Adobe acrobat installed, you can use its preflight feature to get a lot more info about your file.

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Answer 10

Mar 21, 2007 9:52 AM in response to IanB

I think all I need is for the printer to give me the colour profile they will use for their output device and I stand a pretty good chance of getting a reasonable match.

I do not know any way at all to incorporate this into Pages. How were you planning to do it?

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Answer 11

IanB Author

Level 4

1,374 points

Mar 21, 2007 10:12 AM in response to Barbara Brundage

I understand that it is possible to use ColorSync Utility to make your own PDF-X/3 Quartz Filter. Part of this is the ability to designate what destination colour profile to use. Isn't that right?

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Answer 12

Mar 21, 2007 10:19 AM in response to IanB

Yes and no. Are they telling you to do this? Do they know you are not using a graphics program or a high-end page layout program, if so?

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Answer 13

Mar 21, 2007 10:24 AM in response to Barbara Brundage

I would just send them the PDF-X and see what they say, without monkeying around with such complex areas if you don't have the tools to do it well (and the OS X system tools are not sufficient here. ) If they tell you to do it, then worry about it.

EDIT One thing I would definitely do is to go into Adobe Reader and check the embedded fonts (in the properties) before sending it.

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Answer 14

Mar 21, 2007 10:34 AM in response to IanB

I have been playing with this and I very strongly would not recommend it. It is not doing at all what would normally happen (tagging with profile or converting to it).

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Answer 15

Tulse

Level 5

5,806 points

Mar 21, 2007 10:54 AM in response to Barbara Brundage

Sorry for the confusion, Barbara and IanB, as I should have been clearer -- when IanB asked "How would I get at that information via the standard Apple software?", I meant that one can use Get Info on the photo files themselves, and not on the resulting Pages or PDF files.

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