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Convert Photo to CMYK

Aug 11, 2012 3:25 AM

At the moment, I haven't space available to re-add Photoshop to my system, but am seeking to take a black and while photo in my ID layout and ensure that it's in CMYK without ink values exceeding 240% total area coverage, as Acrobat preflight has reported for this image.

 

Can ID (CS3) correct this?

 

The photo is a colour scan of a B&W image. I've tried coverting the image, a TIF file, in Picassa to B&W. However, Acrobat, still shows this image as RGB with values closer to 300% total area coverage. How to handle this, without installing Photoshop? 

 

Thank you

 
Replies
  • Currently Being Moderated
    Aug 11, 2012 4:53 AM   in reply to luca del carlo

    No, ID cannot make corrections like this. I've never used Picassa. Does it allow you to adjust curves or levels? Assigning a profile?

     

    If you converted to B&W, does that mean it was showing black channel only in the original, or does it have multiple channels? If there is only Black in the original image, that means there was a conversion during export (not surprising since we have no idea waht the correct profiles for lightning source are).

     

    I think Rob expained to you before that bitmap and grayscale images in ID are placed on the Black plate of the file, and are presumed to be in the working CMYK color space. If you output to an RGB space you will get a three-color black, which will get converted again to a four-color black in the printer. If you export to a CMYK space the black will also get converted if the destination is different from the working space and you didn't select Convert to Destination (Preserve Numbers). A CMYK file will also be converted to RGB, then back to CMYK, internally in a non-postscript printer, but it seems less likely that is happening at a commercial output service.

     

    Why not scan as grayscale, or are you trying to get a richer tonal range?

     
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  • Rob Day
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    Aug 11, 2012 5:36 AM   in reply to luca del carlo

    but am seeking to take a black and while photo in my ID layout and ensure that it's in CMYK without ink values exceeding 240% total area coverage, as Acrobat preflight has reported for this image.

     

    The photo is a colour scan of a B&W image.

     

    ID is capable of converting to CMYK on export and the conversion will be virtually identical to the one you would get out of PS given the same color settings. Total ink limits are set in the destination CMYK profile when you make a conversion to CMYK, so even if you had Photoshop you would also need a CMYK profile for the press with a 240 limit. If the printer has a real world ink limit of 240% they should be able to provide you with one. 240 is unusually low— the only profiles that ship with CS with total ink under 240 are for newsprint.

     
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  • Currently Being Moderated
    Aug 11, 2012 5:42 AM   in reply to Rob Day

    I'm a little confused here. Luca has said that the image is both color and black and white, and what happens is going to depend which it really is.

     
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  • Rob Day
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    Aug 11, 2012 5:57 AM   in reply to Peter Spier

    I read it as a grayscale image scanned as RGB, so its mode is RGB.

     
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  • Rob Day
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    Aug 11, 2012 7:06 AM   in reply to luca del carlo

    How to handle this, without installing Photoshop?

     

    There's virtually no difference in the way ID and PS convert color so it is possible with the correct profiles.

     

    The .zip archive below includes 2 .icc profiles. MaxBlack.icc will convert a neutral RGB image to the black plate only (effectively it becomes a grayscale). HeavyBlack240.icc puts most of the values onto the black plate but includes some CMY under the black. The total ink max is 240. Neither of these should be used for converting non-neutral color images.

     

    To use, put the profiles in your profiles folder—they should be available as CMYK profiles. Place your image on an ID page and export it as a PDF/X-1a with the Output>Color Destination set to one of the profiles. Place the exported PDF in your layout:

     

     

    http://www.zenodesign.com/forum/NeutralProfiles.zip

     

    Screen shot 2012-08-11 at 10.00.51 AM.png

     
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  • Currently Being Moderated
    Aug 11, 2012 7:32 AM   in reply to Rob Day

    Again, I thnk we may be seing two different interpretations here.

     

    First: "I've tried coverting the image, a TIF file, in Picassa to B&W." makes we wonder if it really is RGB at this point.

     

    The second part, perhaps I'm misinterpreting the intent to make a contrast or total ink correction within ID in the same way you would in Photoshop by adjusting the curves or output levels. Indeed, using a specialty profile during PDF conversion would be an option if there is nothing else on the cover, but it won't work if there's color there too.

     

    It would be good to get some more input from Luca, I think.

     
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  • Rob Day
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    Aug 11, 2012 7:55 AM   in reply to Peter Spier

    makes we wonder if it really is RGB at this point.

     

    It is: "However, Acrobat, still shows this image as RGB"

     
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  • Currently Being Moderated
    Aug 11, 2012 8:08 AM   in reply to Rob Day

    I thought exporting a grayscale to an RGB profile would make it RGB in the PDF, but apparently I'm wrong, or at least Acrobat still lists it as grayscale in preflight (though if you use a print preview with an RGB profile it shows as RGB).

     
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  • Rob Day
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    Aug 11, 2012 8:08 AM   in reply to Peter Spier

    using a specialty profile during PDF conversion would be an option if there is nothing else on the cover, but it won't work if there's color there too.

     

    Just to clearify the profiles I posted have a black generation that's very heavy and only appropriate for neutral images (RGB grayscales). Their  black generation is too heavy for typical color work, but it is also possible to make profiles with 240 total ink and light black generation. The printer should provide one if total ink is really an issue.

     
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  • Currently Being Moderated
    Aug 11, 2012 8:56 AM   in reply to luca del carlo

    Luca,

     

    I think we know this is the same Lighning Source project you were discussing earlier in another thread, so we understand where the 240% is coming from.

     

    What sort of conversions are you able to do in Picassa?

     

    When you place the image in ID, what does the Link Info show for color space?

     

    What have you got in the Export Dialog under Output (a screen shot would be helpful)?

     
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  • Rob Day
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    Aug 11, 2012 9:21 AM   in reply to Peter Spier

    What sort of conversions are you able to do in Picassa?

    Picasa is Google's free editor. My son uses it in school and it looks to me like its only mode is RGB.

     
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  • Rob Day
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    Aug 11, 2012 9:32 AM   in reply to luca del carlo

    The layout is a book cover, in which all images/text are B&W/grayscale.

     

     

    If you export the cover to PDF/X-a using my HeavyBlack profile (see # 5), your grayscales will export unchanged and your B&W RGB will be mostly on the black plate and under 240%.

     

    If you use the MaxBlack profile everything will be on the black plate and you obviously have no total ink problem.

     

    The printer requires that there be no large areas which contain an excess of 240%.

     

    Is there no tech support? Why don't you ask them how you are suppose to convert to 240?

     
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  • Currently Being Moderated
    Aug 11, 2012 12:16 PM   in reply to luca del carlo

    If the image info says grayscale, there should be nothing but black ink, and your conversion to SWOP preserving numbers would maintain that, so I don't understand where the other colors are coming from.

     

    Would you be willing to share the PDF with Rob or I to look at it?

     
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  • Currently Being Moderated
    Aug 11, 2012 12:47 PM   in reply to luca del carlo

    Are you able to use YouSendIt.com? You can send the file to yourself, then send the link you will receive to Rob and me in a Private message to each of us (click our names to go to our profiles, then click Private Message inthe actions on the right).

     

    Sorry to hear you're laid up, but glad that you survived and seem to be recovering.

     
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  • Rob Day
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    Aug 11, 2012 1:04 PM   in reply to Peter Spier

    there should be nothing but black ink, and your conversion to SWOP preserving numbers would maintain that

    Unless the Trans. Blend Space is RGB and the page has transparency

     
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  • Rob Day
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    Aug 11, 2012 1:55 PM   in reply to luca del carlo

    There's no CMY in the PDF you posted everything is on the black plate, so you don't have a total ink problem.

     
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  • Rob Day
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    Aug 11, 2012 2:02 PM   in reply to luca del carlo

    In AcrobatPro or X you can use Output Preview's Show pop-up to see objects by color space.

     

    Everything is visible showing Device CMYK:

     

     

    Screen shot 2012-08-11 at 4.58.35 PM.png

     

     

    There's nothing for device Gray or RGB:

     

    Screen shot 2012-08-11 at 4.58.45 PM.png

     

    Screen shot 2012-08-11 at 4.59.08 PM.png

     
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  • Currently Being Moderated
    Aug 11, 2012 2:33 PM   in reply to luca del carlo

    Sorry for the delay -- out cheering on my daugher in a half marathon....

     

    I also see nothing here but black ink.

     

    Here's the anaylsis report:

    DelCarlo1.png

    Both images listed as grayscale.

     

    Here's an output preview, with total ink highlighting set to 180 and there is no green highlight anywhere. The darkest area I read in the small photo is about 95%, and in the screen cap the cursor is in the lower right corner of the photo and reading 92%:

     

    DelCarlo2.png

     

    Where are you seeing the more than 240%?

     
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  • Rob Day
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    Aug 11, 2012 2:49 PM   in reply to luca del carlo

    I note that in the "Show" section of the output preview, you have "CMYK" selected. On my side, in Acrobat, it was showing "All" by default.

     

    You could also uncheck the black plate and see that there's no CMY;

     

    Screen shot 2012-08-11 at 5.45.51 PM.png

     

    Screen shot 2012-08-11 at 5.48.38 PM.png

     
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  • Rob Day
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    Aug 11, 2012 5:51 PM   in reply to luca del carlo

    Your interior file is a PDF/X-a and your document CMYK profile was Fogra27 which allows 350% total ink. The document's grayscale images are black plate only, the other photos got converted to Fogra and have CMY and could have total ink up to 350%. The CMYK photos also will likely have color casts because the Fogra profile has light black generation—there's no black at all in the 1/4 tones so the press gray balance will need to be perfect in order to prevent casts.

     
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  • Currently Being Moderated
    Aug 12, 2012 1:25 AM   in reply to luca del carlo

    Luca,

     

    Is the interior supposed to be printed in color or black-only? I've been looking through both threads and I don't see that you've told us, but I'm wondering why you would print the interior in color when all of the images are from old black and white photos and you've done the cover as black only. It's OK to convert grayscales to CMYK for a richer look, if you are willing to pay the cost for the additional plates, but we need to clarify what the intended output is here before we can come up with a solution.

     
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  • Currently Being Moderated
    Aug 12, 2012 5:54 AM   in reply to Peter Spier

    The "reviewing a PDF" document that you referenced in #21 above recommends that images for the interior of the book be either 600 ppi bitmap mode (B&W) or 300 ppi grayscale. Clearly a lot of your images were imported as RGB (sill not clear whether you converted the cover art to grayscale in Picassa, or it was always grayscale).

     

    CS6 now supports direct export to composite grayscale, but CS3 does not, so IF you want grayscale images in your PDF you have 2 choices, either convert the RGB to grayscale before placing, or Distill the PDF the old way. If you have Windows, and the virtual PDF printer is installed, you can print direct to PDF and choose Composite Grayscale for the output. On Mac you'll probably need to print to file, then distill manually. See InDesignSecrets » Blog Archive » Acrobat’s Adobe PDF Printer Replaced in Snow Leopard

     

    In either case, if you are trying to convert the RGB to grayscale during output, it is very important to FIRST edit the preference in ID for Appearance of Black and set it to Output All Blacks as Rich Black. Failure to do this step will result in 100%K type and other elements being screened to gray in the low to mid 90% range with only your images containing any areas of 100% coverage.

     

    If you want to output the RGB images as "rich gray" but keep the total ink down to 240%, Export to PDF using Convert to Destination and try one of the profiles Rob supplied above in post #5.

     
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  • Rob Day
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    Aug 12, 2012 6:23 AM   in reply to Peter Spier

    If you want to output the RGB images as "rich gray" but keep the total ink down to 240%, Export to PDF using Convert to Destination and try one of the profiles Rob supplied above in post #5.

     

    The MaxBlack profile I posted does not produce "rich gray" conversions, it converts neutral RGB values to the black plate only—there will be no CMY. Technically they will be CMYK images but effectively they are grayscales.

     

    So here is an RGB image with the document CMYK profile as Fogra27—the 100% (0|0|0 RGB) patch reads 350% total ink:

     

    InDesignScreenSnapz001.png

     

    If I reassign the MaxBlack profile the 100% patch reads 0|0|0|100:

     

    InDesignScreenSnapz002.png

     
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  • Rob Day
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    Aug 12, 2012 6:29 AM   in reply to luca del carlo

    and then in PS convert all these BW pics which are still in RGB to CMYK (or do I try to convert them to greyscale, not CMYK???)

     

    If you care about consistency grayscales will look different than 4-color separations in print—it's very unlikely you'll get neutral gray balance with any of the CS profiles and you would have to use US Newsprint SNAP to stay under 240%.

     
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  • Rob Day
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    Aug 12, 2012 7:32 AM   in reply to luca del carlo

    A grayscale approach would be safer.

     

    Here's an illustration of the potential problems you'll have with 4-color separations. You don't actually know what the profile of the press is—you don't know what mix of CMY would print neutral. If you use the default SWOP profile 157|157|157 RGB converts to a CMY mix with no black (40|33|33|0). It wouldn't take much cyan drift to turn this image green:

     

    InDesignScreenSnapz006.png

     

    My HeavyBlack240 profile replaces much of the CMY with black (19|14|15|17). Still no guarantee that there won't be a cast, but it's a much more forgiving separation.

    InDesignScreenSnapz007.png

     
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  • Currently Being Moderated
    Aug 12, 2012 6:51 AM   in reply to Rob Day

    I just ran across this in an old post from Kris Coppieters of Rorohiko.com, and it might be something else  to look at: http://www.rorohiko.com/wordpress/indesign-downloads/color2gray/

     

    It does color-to-grayscale conversions inside ID.

     
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  • Rob Day
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    Aug 12, 2012 7:14 AM   in reply to Peter Spier

    It does color-to-grayscale conversions inside ID.

     

    Would there be an advantage using their plugin over a black generation profile? The documentation indicates it's not a color managed conversion, and the conversion is to the CMYK black plate.

     
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  • Currently Being Moderated
    Aug 12, 2012 7:45 AM   in reply to Rob Day

    I've never tried it, so I don't know for sure, but I suspect not. Just one more possible route...

     
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  • Rob Day
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    Aug 12, 2012 8:22 AM   in reply to Peter Spier

    I should throw in a disclaimer here, I'm not advocating any approach, but the MaxBlack profile does color manage the conversion. It will produce exactly the same black values you would get if you opened neutral RGB images into photoshop and converted them to Dot Gain 25% grayscale in Photoshop

     

    Here my Working CMYK space is MaxBlack and my Working Gray space is Dot Gain 25% and I'm sampling 134|134|134 RGB. the output to Grayscale is 51% the output to CMYK is 0|0|0|51:

     

    PhotoshopScreenSnapz001.png

     
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  • Currently Being Moderated
    Aug 12, 2012 9:56 PM   in reply to Rob Day

    Hi Rob,

     

    Not quite sure what you're saying. Here's what I know: the color conversion in Color2Gray is color managed, but outside of the user's control. The thing is that we simply use a built-in CMYK to Gray conversion provided by InDesign, as-is. It is a proper conversion (e.g. if you have a purely yellow image, the converted image would show up as light gray), not a mere stripping away of the CMY plates. But from user feedback we know that there are users that would like to apply some curves to the resulting images, because they find them too flat.

     

    Cheers,

     

    Kris

     
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  • Rob Day
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    Aug 13, 2012 5:28 AM   in reply to RorohikoKris

    But from user feedback we know that there are users that would like to apply some curves to the resulting images, because they find them too flat.

     

    By color management I meant the ability to choose a destination gray profile the way you can in Photoshop. Prior to CS6 you could distill (not export) the entire document to grayscale, but there was no destination choice—the numbers indicate to me that the conversion is always to Photoshop's default 20% dot gain.

     

    CS6 still has no grayscale space, placed gray objects are previewed via the CMYK profile when Overprint or Sep Preview is turned on, which I gather is what happens with the plugin. Most CMYK profiles preview 0|0|0|100 black as something less than absolute black (which is what happens on press) thus the flatness complaint. The preview of same gray values via ID's default US SWOP and Photoshop's default 20% dot gain will be different.

     

    I didn't mean to suggest the plugin isn't useful, but in this unusual case a profile also works because the neutral RGB images have equal values. The profile approach would not work for typical color.

     
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