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Author Topic: Profiling and Calibrating papers  (Read 3894 times)

ThePhotoDude

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Profiling and Calibrating papers
« on: July 31, 2008, 08:46:14 AM »

Can someone please explain the difference between calibrating a paper and profiling it?

Thanks loads, John
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digitaldog

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Profiling and Calibrating papers
« Reply #1 on: July 31, 2008, 09:24:20 AM »

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Can someone please explain the difference between calibrating a paper and profiling it?

Thanks loads, John
[a href=\"index.php?act=findpost&pid=212011\"][{POST_SNAPBACK}][/a]


Paper calibration on some devices is critical. Some device, either a densitometer  or better a Spectrophotometer (for papers with optical brighteners) is used to measure the white of the paper for printing calibration. I just did a lot of testing with an HP Indigo digital press and this is such a beast that requires proper paper calibration for each paper used.

A profile fingerprints the entire printing process by reading LAB or spectra data from a large sample of color patches. It defines the printer's color space (and does also take paper white into account). The ink comes into the picture at this point.

Calibration is often a process for a non stable device or when you're using media that isn't clearly understood/defined.
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Andrew Rodney
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ThePhotoDude

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Profiling and Calibrating papers
« Reply #2 on: July 31, 2008, 12:58:51 PM »

Thanks for that , so on my Z3100 with APS and onboard spectro, I should be profiling the papers? Even if they are HP papers?
Or calibrating? Or both?
Because if I have a look at the calibration status, a paper calibration sometimes goes out of date.
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digitaldog

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Profiling and Calibrating papers
« Reply #3 on: July 31, 2008, 01:04:10 PM »

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Thanks for that , so on my Z3100 with APS and onboard spectro, I should be profiling the papers? Even if they are HP papers?
Or calibrating? Or both?
Because if I have a look at the calibration status, a paper calibration sometimes goes out of date.
[a href=\"index.php?act=findpost&pid=212078\"][{POST_SNAPBACK}][/a]

That system probably handles both processes.
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Andrew Rodney
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rdonson

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Profiling and Calibrating papers
« Reply #4 on: August 01, 2008, 08:16:14 AM »

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Thanks for that , so on my Z3100 with APS and onboard spectro, I should be profiling the papers? Even if they are HP papers?
Or calibrating? Or both?
Because if I have a look at the calibration status, a paper calibration sometimes goes out of date.
[a href=\"index.php?act=findpost&pid=212078\"][{POST_SNAPBACK}][/a]

Generally, both but that depends on the papers you're using.  The Z3100 will report the need for calibration on a periodic basis to ensure optimum results.
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Ron

David Good

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Profiling and Calibrating papers
« Reply #5 on: August 02, 2008, 12:37:17 PM »

Calibration brings the device to a "known state"from which to fingerprint (profile) it from. In order for the profile to accurately reflect the device behavior it must remain in that state. Some devices, such as monitors, "drift" more than others from their calibrated state, making it necessary to re-calibrate more often.
HTH.

Dave
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