Profilemakers Correct for Optical Brightener

Bill W

Well-known member
Greetings,

Does anyone know the threshold that will force a check to appear in the Correct for Optical Brightener box in Profilemaker . I am told that the stock was the same for both my P2P run and my profile target run. However, when I slide my measurement file from the P2P run into Profilemaker the "Correct" box gets a check mark; but, when I slide the measurement file from my profile target run into Profilemaker, no check appears in the "Correct" box.

Lab of paper, as read in MeasureTool, from P2P run is 93.1, 1.1, -1.1; and from the profile run it is 93.5, 0.9, -0.8. I am a flexo printer and since we varnish (UV) pretty much all of our labels, I have chosen to include UV varnish on all P2P and profile target runs. Could it be the variance in thickness of the UV is causing Profilemaker to check or not check its "Correct" box? If this is true I would have suspected that the Lab numbers for the paper would have reflected numbers that are farther apart.

Thanks to all that respond.

-Bill-
 
Re: Profilemakers Correct for Optical Brightener

>when I slide my measurement file from the P2P run into Profilemaker the "Correct" box gets a check mark; but, when I slide the measurement file from my profile target run into Profilemaker, no check appears in the "Correct" box.

Are you certain both measurement files are spectral data? Lab only data won't activate the correction.

>Lab of paper, as read in MeasureTool, from P2P run is 93.1, 1.1, -1.1; and from the profile run it is 93.5, 0.9, -0.8

I beleive profile maker is going by spectral reflectance for determining the presence of optical brighteners...looking for absoption below 400 nm, and re-emmision between 400-460...a blue hump, rather looking at particular Lab values. If you open the measurement files in MeasureTool, click on the white patch to get a look at the spectral distribution curve and you should be able to observe the re-emmision. Check out the percentage of re-emmision at about 440 nm between the two measurement files...are they different?

Regarding the optical brighteners correction itself, you may find it value limited as this correction is only applied to the perceptual rendering intent.

I'd love to see the measurement files if your willing to send them to me.
 
Re: Profilemakers Correct for Optical Brightener

>Does anyone know the threshold that will force a check to appear in the Correct for Optical Brightener box in Profilemaker

FYI - Check for remission above 97% at or around 440 nm...this seems to be the trigger (at least a portion of it anyway). Editing the spectral data in a measurement file, the correction was triggered when I changed the paper white from 97% to 97.1% at 440nm.
 
Re: Profilemakers Correct for Optical Brightener

update: Being that I'm now seeing the OB correction activated by reflectance well under 97%, it appears that this is more of a detection of a peak in blue reflectance rather than any individual reflectance value. ..if anyone cares ;)
 

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