Xrite Color Profiles ?

Started Aug 7, 2021 | Discussions thread
Iliah Borg Forum Pro • Posts: 28,899
Re: Xrite Color Profiles ?
2

dddduuuu wrote:

Iliah Borg wrote:

dddduuuu wrote:

Iliah Borg wrote:

dddduuuu wrote:

Brightness 50, Blacks 5, Contrast 50 and Curve Medium Cobtrast makes ACR pipeline true linear.

You got it exactly wrong.

Here is our artice that explains the issue https://www.rawdigger.com/howtouse/overriding-raw-converter-default-adjustments-settings

you've missed the main point.

Try your setting instead without modifying the dcp to make the embedded curve (0,0) (1,1) and prove the resulting numbers for G with gamma 1 form a linear progression, increasing 2x per stop.

If DCP-profile doesn't have ProfileToneCurve tag, ACR applies the default one

"

To embed a linear curve into an existing profile, I use a very fast, reliable, and simple method:

> exiftool -ProfileToneCurve="0 0 1 1" -o new.dcp old.dcp

"

Are you suggesting that a user does the above (as in my comment to the article)? If so, IMHO you should have explained it explicitly, starting with what is "linear profile" in your "Just reset, then select linear profile and PV2. "Zero" of some adjustments is set with non-zero value. Brightness 50, Blacks 5, Contrast 50 and Curve Medium Cobtrast makes ACR pipeline true linear" and how to make one.

Iliah, i've made some research to explain you more clearly what I mean.

...

Max DE with your settings for linear process (profile Adobe Standard, Process Version 2, Blacks 0, Brightness 0, Contrast 0, Curve Linear)

That's not my settings, as shown on Figure 13 on our https://www.rawdigger.com/howtouse/overriding-raw-converter-default-adjustments-settings, we account for baseline exposure:

Figure 13. PV 2 (2010), zeroed-out defaults, 0.25 BaselineExposure subtracted

We are discussing here profiles created by X-Rite ColorChecker Camera Calibration tool. Fact is, the option to create linear profiles was added to X-Rite profiling engine SDK only May 11 2021, after much pressure from our side. Did it make to the end-user product? AFAIK it's a no. That triggered my response. If you read our page, modification to make a DCP profile linear is mentioned in my comments, as I already said.

I have many different cameras of different brands, a studio with stable lights, and I check things based on my own shots, taken in tightly controlled environment, against the target spectral response measurements. On a side note, Dan Margulis is famous not for being blind. With un-modified DCP zeroing-out the settings in ACR results in normal saturation and normal brightness, no acid colours any more.

I don't see this discussion as a useful one.

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