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Image profile for printing through QTR

Image profile for printing through QTR

2018-06-08 by skapuskar@...

I have made three prints of step wedges, each with a different embedded profile:

-Grey Scale 2.2
-QTR Grey Lab
-untagged


All were printed separately with Print Tool, Color management turned off, using the same QTR b/w starter profile.

The 3 results measured with an i1pro turned out identical. The embedded profiles did not have any impact, how is this possible?


Thanks


Sidney

Re: Image profile for printing through QTR

2018-06-09 by richard@...

Did you convert to or assign the profiles? If just assign then they should just appear differently on the display but the actual image bits stayed the same if not applying colormanagment in print tool.

It is when you assign and then convert or directly convert where you will see a difference. I am writing up something for my digital negative workshops about different inverting methods using assign/convert to different color spaces for getting more/less contrast with the same QTR curves. It really depends on the kind of images you’re working with, but it can make some things pop just a touch more than straight GG22 with no CMS.

Richard Boutwell

Re: Image profile for printing through QTR

2018-06-09 by James Wille

In order for embedded profiles to have any impact on the prints color management has to be active.

Sincerely,

Oz Wille

Sent from my mobile device

Re: [QuadtoneRIP] Image profile for printing through QTR

2018-06-09 by Roy Harrington

Sidney

This is the main feature of No-Color-Management. By turning off color management you want to ignore
whatever profile is embedded in the file. Usually step wedges are "untagged" to emphasize this.

In general for all the usual uses or step wedges -- QTR driver linearization or ICC profile creation --
you never want to convert or change the values in the wedge and they should be printed with NoColorMgmt.
(it doesn't actually harm to "assign" a profile but I think it can lead to confusion like this)

Roy
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On Fri, Jun 8, 2018 at 12:49 PM, skapuskar@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:


I have made three prints of step wedges, each with a different embedded profile:

-Grey Scale 2.2
-QTR Grey Lab
-untagged


All were printed separately with Print Tool, Color management turned off, using the same QTR b/w starter profile.

The 3 results measured with an i1pro turned out identical. The embedded profiles did not have any impact, how is this possible?


Thanks


Sidney






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Re: [QuadtoneRIP] Image profile for printing through QTR

2018-06-09 by skapuskar@...

My profiles are all embedded, not just assigned.
I made some test prints today and, effectively, no matter what profile used, as long as color management is turned off, there is no impact.
With color management turned on, the differences of the gray scale profiles (Gray Lab, Gray Gamma 2.2 or even untagged) are very minor.
In any case, I believe it is best to stick to a fixed setting and correct with a QTR grey curve and linearization.

Thank you all for your input and help.

Sidney

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