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  #1 (permalink)  
Old 08-06-2007, 12:35 PM
Lefkoff Lefkoff is offline
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Does anyone make this?

Let me start off with some background...
1) I am familiar with a densitometer and what it does
2) I am familiar with a Pantone Color Cue and what it does
3) I am refering to 4 color printing on a U.S. sheetfed press
4) Forgive me if this is a really stupid question

Does anyone make a densitometer-like device that you can lay down on a press sheet over a solid color and it give you the CMYK breakdown of that color?

In other words, if I place the device on the press sheet over a green color it would tell me how much CMYK was in that color.

If such a device exists, could someone please give me its correct name and perhaps a place to get one. Any help would be VERY appreciated.
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Old 08-06-2007, 12:43 PM
ajr ajr is offline
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We used to have a Xrite densitometer that would give you the LAB values of a colour, you could then put these into quark and convert it to CMYK not perfect but pretty good. Look at their website. I think one of our minders nicked it.

Aj
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Old 08-06-2007, 12:53 PM
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colorblind colorblind is offline
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As far as I know, no densitometer can do that. Densitometers can tell you how much light is being reflected to it's filters but that's it. In fact, a densitometer has no clue what a "50% Cyan dot" is. What it does is comparing the reflectance, through a color filter, of a light density of a certain color to a solid density of the same color and by using an equation (Murray-Davies or Yule-Nielsen) gives you a screen % estimation based on that equation. A spectrocolorimeter or spectrodensitometer will give you lab values of a certain color but it will be up to you to translate these values to CMYK depending on the ICC profile you want to use.

Hope this helps.
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Old 08-07-2007, 12:53 AM
ajr ajr is offline
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My mistake I think it was a spectrodensitometer.

Aj
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Old 08-07-2007, 09:56 AM
Kid_Leo Kid_Leo is offline
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I had some software that came with a Colortron that used to do it. But as colorblind alread said, the values that you would get changed based upon the settings such as profiles, intents, etc.

I think I see where you are going with this and I don't think you can get there from here. Correct me if I am wrong but you want to take a certain patch of CMYK color on a press sheet and determine what screens were used to make it up. The problem is that a spectrophotometer can only tell you what "color" the patch is and you need something (software) that determines how to make that color out of CMYK. Unfortunately there are multiple ways to achieve the same color in CMYK i.e. take away a little CMY and add a little black and theoretically you get the same result. Throw in the problem of dot gain and it is next to impossible to determine exactly how something was printed with any kind of device.

If you take a spectrophotometer and read a patch from a Pantone process color guide and it would probably give you a value that has some of all 4 colors even though the patch is only printing in 2. Sometimes a loupe and a calibrated eye are sometimes better than the most sophisticated device.
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Old 08-07-2007, 02:53 PM
b4press b4press is offline
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We use Color Science Software and in the press check software you have color tools that basicly read color with a spectro and then the software will use our "master color profile" to come up with a cmyk mix.
It has been pretty reliable. I use it quite a bit when we have to match a sample from an unknown origin.
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Old 08-08-2007, 01:19 PM
Jim Stone Jim Stone is offline
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The Eye1 comes with freeware that will do this.
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