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Thread: Accuracy of ImageViewer color values

  1. #1
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    Default Accuracy of ImageViewer color values

    We have a PDF that has a blue CMYK build of:
    98 52 1 4

    After the file is rasterized, ImageViewer displays the CMYK values as:
    87 43 6 4

    How accurate is ImageViewer at displaying the actual CMYK values that will print?

  2. #2
    StarDigital is offline Fiery Forum Expert Contributor StarDigital is on a distinguished path
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    you need to remember that the values that are in your pdf go through more proccesses before the rip is done. GraCol and other CMYK source profiles adjust the pdf values, and so does your output profiles. The end result is what is shown on the Image viewer. To make your values closer you can choose to bypass the source profiles, this has pros and cons:

    Pros: the colors will seem richer, so it is good for some jobs that are mostly graphics
    Cons: the colors are not accurate to what it is supposed to be, or to industry standards

    It all depends on you and your customer. I found all this out the hard way, and there are still times i will go back to bypass, though less often now.

    Dan

  3. #3
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    Thanks very much Dan.
    This particular customer's jobs actually come in with Pantone 293. Prepress converts this to RGB in PitStop, then it is processed on Fiery to yield the CMYK values, and this has worked for this customer for quite some time, to give them the color they want.
    I intended to change this workflow by using PitStop to convert directly to CMYK values instead of RGB.
    But since the color profile doesn't yield the same CMYK values after raster, I think it would be better to leave the 293 alone and implement a special Spot Color replacement on the Fiery instead.

  4. #4
    StarDigital is offline Fiery Forum Expert Contributor StarDigital is on a distinguished path
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    Indeed, there are several conversions going on before the rip and yes that isn't good. Question doesn't your CWS have Pantone libraries?

    Dan

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    Yes, I have already created a Group in Resources | Spot Colors, and copied Pantone 293 C for editing to match what the customer wants, using 'Substitute colors' in the preset. That's the way it should be done, so I'm just trying to get there and make sure I've covered all the bases.
    Thanks again for your helpful responses.
    Last edited by printmeister; 08-31-2015 at 08:10 AM.

  6. #6
    adam1991 is offline Fiery Forum Expert Contributor adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful
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    hang on here. LOTS of stuff going on inside of all of this.

    Substitute colors is NOT the workflow. Just edit the Pantone color as desired, and make sure that spot color matching is checked in the color flow part of the job ticket.

    Leave spot colors--named colors--with the name, and make sure there's a corresponding name in the spot library. Convert spot to RGB? Insane. Convert to CMYK? No need--the Fiery has all the high-dollar software built into it to convert the spot name to CMYK **for that specific engine and print condition.**

    What you see in ImageViewer is the result of quite a few separate processes. If you print a named spot color and you have that named spot color defined inside your spot color list, then what ImageViewer will show you are those CMYK values you defined. It's showing you that indeed, the Fiery saw that named color and looked it up in the table and used it.

    If you send a CMYK value, if you have CMYK simulation turned on (normally you do) then the CMYK gets turned into slightly different CMYK values, depending on the simulation. That's what ImageViewer shows.

    Beyond that, what ImageViewer doesn't show is the result of calibration. The values you see in ImageViewer may/will be slightly altered due to calibration, which is the final process the raster image goes through on its way to the engine.

    It's more involved than we have time or room for here, but that's the gist.

  7. #7
    StarDigital is offline Fiery Forum Expert Contributor StarDigital is on a distinguished path
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    All true and in addition, the spot color will be pulled from the output profile it is linked to. SO:

    in properties:
    The output profile needs to be set OR (use media defined) paper catalog for that item is set for the Output profile

    In Device center/resources/spotcolors the [properties] needs to be set to the output profile for the changes in the PANTONE color to take effect. (The load time for this is long so a faster way would be to set the default as the one you are using (Color setup))

    so, for example, any change to coated 120 will not affected uncoated 90 they must be the same.

    dan

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    adam1991 is offline Fiery Forum Expert Contributor adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful
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    yes. 100%.

  9. #9
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    Thanks Adam and Dan - I went to 'Color | Basic Settings...' and enabled Spot Color Matching and disabled Substitute colors.
    I knew converting to RGB was not the right way, but that's the way they did it until I just came on board - I'm just trying to change that.
    I should add that I think we can still use Substitute colors, as some PDF files from this customer do come in with a CMYK build of 293, and sometimes an RGB build - we need to replace whatever comes in with the changed values.
    Last edited by printmeister; 08-31-2015 at 11:25 AM.

  10. #10
    adam1991 is offline Fiery Forum Expert Contributor adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful adam1991 has proven very helpful
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    Substitute colors IS the tool for changing inbound CMYK or RGB into known values, but the spot color editor is the tool for defining what CMYK values you want named colors to put down.

    And actually, with spot colors, you shouldn't have to adjust them--if you're creating and using calibration/profile sets correctly. In theory, you shouldn't be able to improve upon what the Fiery does to make the best representation of a Pantone color.

    That is, unless the Pantone color in question is not in the library...in which case you can add it, but you should add it with the name and define it in L*a*b* values....

    I said there were lots of moving pieces in all of this.

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