I use ColorThink or Babelcolor to evaluate the maximum black that a specific paper/printer combination can produce. But for those that don’t have those programs, is there a website where you can upload a profile and get a Lab-value of the black and white point of that profile? Best Stefan Ohlsson Projektor Utbildning AB Telefonvägen 30 SE-126 26 Hägersten Sweden www.korta.nu/profiler “Everything should be as simple as it can be, but not simpler." Albert Einstein
On Jul 1, 2015, at 2:42 AM, Stefan Ohlsson <stefan@profiler.nu> wrote:
I use ColorThink or Babelcolor to evaluate the maximum black that a specific paper/printer combination can produce. But for those that don’t have those programs, is there a website where you can upload a profile and get a Lab-value of the black and white point of that profile?
Convert 0/0/0 in Photoshop to the output profile's black and read the lab value in Photoshop? Andrew Rodney http://www.digitaldog.net/
From: Andrew Rodney
I use ColorThink or Babelcolor to evaluate the maximum black that a specific paper/printer combination can produce. But for those that don’t have those programs, is there a website where you can upload a profile and get a Lab-value of the black and white point of that profile?
Convert 0/0/0 in Photoshop to the output profile's black and read the lab value in Photoshop?
You want to start with a document in the printer's color space. Then use Andrew's suggestion of reading the Lab values of black and white. As to web sites for profile evaluation, I know I have seen more than one, but I don't have the links at hand. Note: Depending on the profile, a pure black may not be the darkest (minimum L*) value the printer color space contains, but it should be close. -Ethan
Sometimes the easy ways sneak under your radar. But I noticed something odd when I followed your advice. I expected to get the same result if I used perceptual rendering or if I used relative colorimetric with black point compensation. But no, at least on the 4 profiles that I tested. Best Stefan Projektor Utbildning AB Telefonvägen 30 126 26 Hägersten Sweden www.korta.nu/profiler “Everything should be as simple as it can be, but not simpler." Albert Einstein
Stefan Ohlsson wrote:
But I noticed something odd when I followed your advice. I expected to get the same result if I used perceptual rendering or if I used relative colorimetric with black point compensation. But no, at least on the 4 profiles that I tested.
The black point of a CMYK device is something of an arbitrary choice. It depends on the maximum ink you want to use as well as any black chromaticity target, and it may also depend on how gamut clipping is handled, if the chromaticity target isn't achievable. And then if you are depending on the B2A table to look it up, it may not be represented terribly accurately in the profile compared to a black point tag. Graeme Gill.
CMYK profiles are indeed a different thing, but I was checking RGB printer profiles. Stefan
2 jul 2015 kl. 02:54 skrev Graeme Gill <graeme2@argyllcms.com>:
Stefan Ohlsson wrote:
But I noticed something odd when I followed your advice. I expected to get the same result if I used perceptual rendering or if I used relative colorimetric with black point compensation. But no, at least on the 4 profiles that I tested.
The black point of a CMYK device is something of an arbitrary choice. It depends on the maximum ink you want to use as well as any black chromaticity target, and it may also depend on how gamut clipping is handled, if the chromaticity target isn't achievable. And then if you are depending on the B2A table to look it up, it may not be represented terribly accurately in the profile compared to a black point tag.
From: Stefan Ohlsson
Sometimes the easy ways sneak under your radar. But I noticed something odd when I followed your advice. I expected to get the same result if I used perceptual rendering or if I used relative colorimetric with black point compensation. But no, at least on the 4 profiles that I tested.
Best
Stefan
You'll get the most accurate results using Absolute Colorimetric rendering. As Graeme mentioned, CMKY profiles (or worse still multi-color) throw additional variables into the mix. Using Photoshop will get you close to the actual values for white and black.
participants (4)
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Andrew Rodney
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Ethan Hansen
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Graeme Gill
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Stefan Ohlsson