Understanding ICC profiles - further questions

[rrojas]

Hi all,

I hope you are all well.

After all the reading and (successful) use of the ICC profiles for printing, there are still two issues I am not able to grasp completely…

1. Why linear results (that accurately translate greyscale tones to the corresponding luminosity values on paper) look dull to the eye, and not equal to what we see on the monitor? I guess the answer is related to the fact human eyes do not respond linearly to luminosity values, and the concept of gamma (file and monitor),… but I do not know exactly how to put that together. Walker, for those like us who need to understand what is going on, could you please elaborate why when printing tones totally linear (aka correct) the results do not look like the image our monitor shows us?

2. When we create and use an ICC to print with Piezography, I understand that the ICC will not only correct the tonalities to bring them to totally linear, but ALSO provide a contrast boost to match the print to screen. My question is: Is that contrast boost a “standard” and invariable curve that is applied, no matter which monitor I have, etc? Is that a curve “created” by an algorithm of Xrite, but based on which parameters more or less? I am trying to understand where that contrast boost is coming from, and at which point it reflects my particular setting (monitor, etc) or just a universal one.

3. You mention on the documentation that using the ICC alternative with Piezography is akin to using a Color Management process in colour printing: that is, obtaining a ICC through Xrite Profiler and then using it to print. My question is: Does that mean that whenever we follow a color managed process in colour printing, the ICC created by Xrite I1Profiler software will also “encapsulate” a contrast boost to match print to monitor? I thought this Software were simply correcting the deviations between colours sent to the printer and colours printed…

In other words, which is the difference in the way the Piezography ICC adds a contrast to de-linearize results, and what conventional colour ICC profiles do?

Sorry for the questions. I know many people will say, just use the tool! But using tools without really understanding the logic of it does not work in my case.

Thanks in advance,

Rafael

[PiezographySupport]

@rrojas

Why linear results (that accurately translate greyscale tones to the corresponding luminosity values on paper) look dull to the eye, and not equal to what we see on the monitor? I guess the answer is related to the fact human eyes do not respond linearly to luminosity values, and the concept of gamma (file and monitor),… but I do not know exactly how to put that together. Walker, for those like us who need to understand what is going on, could you please elaborate why when printing tones totally linear (aka correct) the results do not look like the image our monitor shows us?

This is because you are most likely no soft-proof with an appropriate Piezography ICC profile and with Preserve RGB numbers clicked on in Photoshop. Make the monitor = the printer (monitors are also not linear by default). This has been talked about in length in other threads I believe (with you).

The end of this video describes is in detail: https://shop.inkjetmall.com/icc-profiling-piezography

@rrojas

s that a curve “created” by an algorithm of Xrite

yes. It’s called a “transfer curve” and each ICC vendor has their special sauce.

@rrojas

the ICC created by Xrite I1Profiler software will also “encapsulate” a contrast boost to match print to monitor?

yes.

@rrojas

I thought this Software were simply correcting the deviations between colours sent to the printer and colours printed…

Nope, they are also compensating for the differences in contrast in the medium (more contrast needed on matte compared to glossy) vs your monitor. Thus the S curve, or dip curve (in the case of QTR-Create-ICC).