Datacolor User to User Support Group.

On Jan 10, 2010, at 5:37 AM, marko.mili wrote:

>
>
> David, thank you for detailed response.
>
> I have some doubts, however, that this is the correct solution and  
> this is why:
>
> Profile that is selected under ColorSync is supposed to be profile  
> for the printer/media. ColorSync will take your data and convert it  
> to this profile before passing it to print driver. The only way you  
> can get ColorSync to not molest your data is by tagging your data  
> with the same profile that is selected in ColorSync. So if this is  
> going to work, you are either tagging your data with "Generic RGB",  
> or ColorSync assumes that untagged data is in "Generic RGB" (I'll  
> assume you are sending untagged data). I do not believe this could  
> in any way have anything to do with Canon drivers as such.
>
>

I wouldn't have written all of that if I didn't know for a fact that  
it works...:-)

I've tried this, and tested it, and: it works.

> I tried printing the target another way: I opened it in PS, assigned  
> it an RGB profile,
>

Why? I didn't say to do that.
> saved it, opened it in Preview, printed it ColorSync and the same  
> profile.
>
Why? I also didn't say a thing about opening anything in Preview and  
printing it.
> Result was very similar to your suggested method. At first glance I  
> thought it was the same, but on closer inspection I realized it was  
> different and measurements confirmed it. I profiled both ways, and  
> it was clear that the second method was the right one.
>
>
Taking the .tif (which is untagged); assigning a profile to it;  
resaving it; and opening
it in Preview; and then printing it; is going to end up changing the  
internal RGB
values in the image, most likely. That's why we've never mentioned  
this or told
anyone to do it.

We have two official methods for printing targets:

- Directly from Spyder3Print, in which case, there are no ahead-of- 
time color management
controls to set. Spyder3Print sends the non-adjusted RGB colors for  
the patches straight
into the printer driver, and the only place where color management  
would potentially
happen would be inside the printer driver. Disabling it comes down to  
turning it off
in the printer driver, whatever technique is needed to do that. How  
the driver "runs"
this way also has to match how it eventually "runs" when printing from  
inside other
applications, typically Photoshop. The test I'm going to describe  
below proves this.

- Directly from Photoshop, in which case, you need to set up Photoshop  
to warn on missing
profiles (the targets are deliberately untagged), and then tell  
Photoshop not to color
manage the target .tif when it opens. And then you print, with "No  
Color Management" in
the Photoshop print dialog.

See below for how I tested and confirmed that all of this works, and  
"lines up" correctly.
>

> Please let me know if you are able to verify these results.
>
>
I'm not going to spend time trying other things, because I've already  
tested and verified
everything that I already wrote up and told you (and everyone else  
who's reading this)...:-)

Here's a little more info:

- I printed the 225 patch target directly from Spyder3Print, under  
Snow Leopard,
using exactly the procedure I described above. ("ColorSync/Generic  
RGB" to turn
color management "off").

- I loaded the .tif version of the target directy into Photoshop,  
without assigning
a profile (instead, telling Photoshop not to color manage the  
document), because that's
the standard procedure for printing targets from Photoshop. Then I  
printed it with
"No Color Management" in Photoshop's Print dialog. As I've described,  
the Color Matching
pane in the SL print dialog comes up with both radio buttons dimmed  
and ColorSync selected.
(But I've never any specification of Generic RGB or any other profile  
in Photoshop).

- Both target prints not only look exactly the same, but they MEASURE  
exactly the same.
There's no difference. That proves that Photoshop's internal plumbing  
for disabling
color management is effectively pushing through "Generic RGB", even  
though you never
see this happening.

There's really nothing else to say about this...:-) What I've  
described for you
works; I've tested it; verified it as described above (and also built  
profiles this
way, and printed through the profiles, and they're fine); and all of  
the people who
have used this information in support tickets on the Datacolor site  
have been happy
and said that it solved their problem.


David Miller
Senior Software Developer, Digital Color Solutions
Datacolor