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Author Topic: Palo Duro Smooth Rag 310  (Read 592 times)

Alan Goldhammer

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Palo Duro Smooth Rag 310
« on: December 03, 2018, 01:45:20 PM »

Interesting review of the new Red River paper but I confess to being confused.  Mark notes that the difference in L* black point from the profile data but when one looks at data from an actual reading on the paper they appear to be identical at L* = 20.  I'm trying to understand why the difference in profile values for the black point lead to the tonal separation that one sees in subequent data given that regardless of the profile, the printer can only print max black of one value.  Maybe this was discussed during the last iteration of posts about M3 data, I can't remember.
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Mark D Segal

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Re: Palo Duro Smooth Rag 310
« Reply #1 on: December 03, 2018, 02:33:49 PM »

Interesting review of the new Red River paper but I confess to being confused.  Mark notes that the difference in L* black point from the profile data but when one looks at data from an actual reading on the paper they appear to be identical at L* = 20.  I'm trying to understand why the difference in profile values for the black point lead to the tonal separation that one sees in subequent data given that regardless of the profile, the printer can only print max black of one value.  Maybe this was discussed during the last iteration of posts about M3 data, I can't remember.

Hi Alan, thanks for bringing this up. I do strive for maximum clarity, and I acknowledge that this subject matter can be confusing because of the number of variables at play, so if you are confused it could also mean that more or modified explanation is needed, so I'll take a stab at sorting it out. The disconnect in Black Point readings between what the M3 profile says when viewed in ColorThink Pro (L*1) and what comes out on paper when reading the Black patch with an i1Pro2 (L*20) happens on account of the disconnect that occurs when you create the profile using M3 measurement condition with a polarizer, but then read the results on paper from using that profile with an instrument that can only read M0/M1/M2 (all non-polarized). I don't know the physics or math of why that happens, but it does.

So, leaving the world of the profile and ColorThink Pro, and entering the world of the print and an i1Pro2 spectrophotometer, whether the print is made with their M3 profile or my M0 profile, when you measure the blackest Black patch that was laid down on paper, and you are making this measurement on both prints with an M0/M1/M2 instrument (e.g. XRite i1Pro2), you do indeed find that the value returned is L*=20. And when I look at the quality of the black with my own two eyes (forgetting all the instruments and measurements) in both target prints, it does look more like an L*20 Black than an L*1 Black. So, let us take as understood that whether using one profile or the other, the maximum black for this paper measures and looks pretty much the same when the same instrument is used for the measurements on both target prints.

The question of how the deep end of the tonal range gets reproduced from that point upward is another matter, and on this one, the measurements (using M0 measurement condition) and the prints of a deep shade target image (the Romans 16 low key B&W), are coherent and both indicate that the M3 profile used with Relative Colorimetric Rendering Intent does indeed provide enhanced tonal separation (higher contrast range) from L*20 to L*35 compared with the M0 profile. But you can tweak the M0 result to just about emulate (finicky adjustments) what the M3 does without tweaking. So the M3 does good things for Black shading appearance even though at the bottom end of the tonal range there is only so much blackness that a matte paper can reflect regardless of the profiling method.

Does this help?
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Mark D Segal (formerly MarkDS)
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Alan Goldhammer

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Re: Palo Duro Smooth Rag 310
« Reply #2 on: December 04, 2018, 07:44:50 AM »

Mark, it helps a bit.  When this discussion first took place some months ago I went back to my college physics text book on optics to see if there was anything there that would help out on this (there was not and I took physics way back in 1966!).  It may be that M3 measurements are in a sense artificial as they result in the paper black point that is not observable by eye.  That being said, the low L* value ends up spreading out the dark end of the B/W 'spectrum' beyond what can be obtained with M0 measurements.  Even following 'compression' of the spectrum on paper, this spread, while nuanced, ends up yielding separation of dark values that are not obtained with a profile made via the conventional route.  I hope this makes some sense as it's the only thing that I can come up with.

IIRC, this type of profiling was only useful for matte papers and gloss papers don't exhibit the same phenomenon.
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Mark D Segal

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Re: Palo Duro Smooth Rag 310
« Reply #3 on: December 04, 2018, 10:18:41 AM »

Hi Alan; yes, it's a way of trying to improve black tonal appearance for matte papers. Not necessary for gloss and luster which these days have excellent properties in this respect.

As to why the M3 profiling produces the profile data that it does (and actually improves deep shade tonal separation), I tried internet searches every which way from Sunday and couldn't find anything useful. I believe the folks at Chromix do understand it and if they are reading this, maybe one of them can pitch in and explain the physics. From all I've read, it has something to do with how polarization filters glare and just picks up the colour itself, but that doesn't tell me much - especially how it relates to influencing profile behaviour and what we actually see on paper.
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Mark D Segal (formerly MarkDS)
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Alan Goldhammer

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Re: Palo Duro Smooth Rag 310
« Reply #4 on: December 04, 2018, 01:25:05 PM »

https://forum.luminous-landscape.com/index.php?topic=118349.0

is the previous thread from a year ago on this topic.  You and I along with others commented on the M3 profiles and there was some skepticism from some well known folks.  I honestly don't know what to make of all this.  To quote the famous Buffalo Springfield song, 'For What It's Worth,' "There's something happening here, what it is ain't exactly clear"

Alan
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Mark D Segal

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Re: Palo Duro Smooth Rag 310
« Reply #5 on: December 04, 2018, 01:55:16 PM »

I don't pretend to understand the inner workings of polarized spectrophotometry either, but I'm guided by what I see on paper after reasonably in-depth testing, and that's what I wrote-up. The folks can be as skeptical or accepting as they wish. I like your Buffalo Springfield quote - fits well here! :-)
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Mark D Segal (formerly MarkDS)
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