Re: Scanner Profiling Issue
Re: Scanner Profiling Issue
- Subject: Re: Scanner Profiling Issue
- From: John Castronovo via colorsync-users <email@hidden>
- Date: Fri, 15 May 2020 12:32:08 -0400
- Importance: Normal
To clarify what I wrote earlier, if you remove the embedded profile, you'll
be left with the un-interpreted scanner values which is what you want to
create your own profile. However, whether those numbers are raw or not
depends on the scanner software. As Jon says, turn off any automated
settings for end points and curve adjustments. Also, depending on the
software, scanning in 16 bits might get you closer to the raw output of the
scanner. Once you create your profile, for production you'll just replace
whatever profile the scanner assigns to the scans with your new profile by
assigning it to the production scans which need to be done using the same
settings you had when you made your profile. Then convert it to your
preferred working profile using absolute rendering. I like DonRGB, but the
choice depends on your type of work.
john c.
-----Original Message-----
From: Jon Meyer
Sent: Friday, May 15, 2020 11:45 AM
To: John Castronovo
Cc: Chase ; email@hidden ; Pat Herold Chromix
Subject: Re: Scanner Profiling Issue
Traditional scanner calibration and profiling:
1) Turn off all AI / conversion functions
2) Dynamic range - Use fixed end points for enter white and enter black
3) Establish brutal gradation
4) Automate this calibration routine for each production scan
5) Build input profile
6) Test workflow using fully manual conversions
7) Test automated workflow and compare results by using Photoshop eye
dropper.
Jon
Sent from my iPhone
On May 15, 2020, at 10:14 AM, John Castronovo via colorsync-users
<email@hidden> wrote:
An embedded profile cannot change the values. They are what they are
unless a profile interprets them differently. What you need to be
concerned about is the stability of the scans. If they vary depending upon
content or for any other reason, you can't profile that scanner. The other
thing that could be raising your numbers is optical flare and that will
certainly cause issues. Make sure everything in the optical path is clean.
John C.
Techphoto, llc
-----Original Message----- From: Chase via colorsync-users
Sent: Wednesday, May 13, 2020 6:58 PM
To: email@hidden ; Pat Herold Chromix
Subject: Scanner Profiling Issue
Hi,
I've been trained to profile digital devices by (after calibration) first
turning off all color management meaning no profile application to the
output, making a "raw" output and opening it in a profiling application to
make an ICC input profile.
I'm running into a problem trying to profile a scanner whose software
interface will not allow you to turn off the color management on any scan.
I was told by the manufacturer to just discard the embedded profile (in
Photoshop) prior to creating and opening the now supposed "raw" scan used
to make a profile in Xrite or other applications.
When tested in Photoshop, the supplied initial embedded profile supplied
and recommended to use during profiling by the manufacturer raised all the
"L" values about seven "L" so it did change the "raw" values of the
scanner for every scan. To my mind, if a "raw" scan is not truly "raw," it
will not profile correctly. Testing the resulting new input profile had
problems with tone values, gray and color hues.
Therefore, their assumption of just discarding a profile in Photoshop will
not create a truly "raw scan?" I have not seen it. Any ideas? Is there
any way I can traditionally profile this type of scanner? That is the
problem I am trying to solve.
Thanks for your opinion,
Randy ZauchaManaged Color
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