When I print a step wedge image either untagged (workspace Gray Gamma 2.2), converted to Dot Gain 20, converted to Gray Gamma 2.2 or converted "Generic Gray 2.2 Profile" with Epson ABW they all print the same L* values. If instead I assign Generic Gray Gamma 2.2 Profile (so the OS tranform doesn't shift K values) the output is very different. The developer of Quadtone RIP has also noticed that OS-X is making this conversion for any file destined for printing on his RIP. On 8 Mar 2012, at 20:00, colorsync-users-request@lists.apple.com wrote:
From: Doyle Yoder <doyle@dypinc.com> Date: 8 March 2012 16:05:42 GMT To: "'colorsync-users?lists.apple.com' List" <Colorsync-users@lists.apple.com> Subject: Re: Why is OS-X imposing a profile conversion of all greyscale images to "Generic Gray Gamma Profile 2.2"?
This sounds like a printer driver issue to me.
A true RIP would not be using a printer driver.
In reference to PSCS5 no longer having the No Color Management settings, which seemed to have been a knee-jerk response to improperly written printer drivers at the time PSCS5 was being written.
There are no profiles applied in the driver when printing B&W to Canon iPF printers so I don't see this as an OS problem.
Doyle
On Mar 8, 2012, at 9:48 AM, Steve Kale wrote:
From: Ernst Dinkla <E.Dinkla@onsneteindhoven.nl> Date: 8 March 2012 17:22:20 GMT To: Colorsync-users@lists.apple.com Subject: Re: Why is OS-X imposing a profile conversion of all greyscale images to "Generic Gray Gamma Profile 2.2"? Reply-To: E.Dinkla@onsneteindhoven.nl
On 03/08/2012 05:05 PM, Doyle Yoder wrote:
There are no profiles applied in the driver when printing B&W to Canon iPF printers so I don't see this as an OS problem.
Doyle
Is there no difference in the prints when you print the same B&W image with Gamma 1.8, Gamma 2.2, Dotgain 20, untagged, through that route?
Not just ABW but other driver's B&W modes rely on the driver CM that usually expects sRGB or AdobeRGB or Gamma 2.2 assigned images. The HP recommended B&W workflow is "ABW" with driver CM on.