Re: From Camera to printer
Re: From Camera to printer
- Subject: Re: From Camera to printer
- From: EPP_BSI <email@hidden>
- Date: Thu, 31 Oct 2002 11:12:16 -0800
Hello,
1. You go to the effort of using a profiled environment and the
discard it
all why?.
Now that the pixels are correct, what do I still need the profile for?
It fulfilled it's purpose to get me the "correct" pixel values for a
specific output device. I would even consider this image now unsuitable
for any other output device.
2. The profile is a description of the image, should you need to
repurpose
the image the profile information will be invauable.
This image is now "correct" for only one specific device. If I
repurpose it, I would go back to the image that generated it/the
original. From what I understood, the profile is NOT a description of
the image, but a description of an output device; a means to create
correct pixels for what I see on my screen.
3. If you use the colour management polices in photoshop correctly the
image
will be displayed correctly regardless of your colour settings as
Photoshop
will use the embedded profile information to govern the display.
Picture this scenario. A printer supplies you with a profile for the
output device. E.g. the proofer. Now you correct all your images and
convert them at the end to that target profile. Appearance stays the
same, pixels change accordingly. Now that the pixels are correct, it
should not matter anymore if the image is tagged with a profile or not.
The only thing that matters is that the proof will look correct,
according to the pixel values. E.g. place images in Quark, make
postscript or pdf, rip it and output it. The output should be exactly
the same regardless of whether the image is tagged or not. If any other
device would change any pixel values at that point, it would totally
defeat everything you did on the front end, right?
You should care how your images look on your screen and that they match
the proof you would get from me. It really does not matter to me how
the images look on e.g. my screen as long as you are happy.
I think this is where my confusion comes in. There must be 2 completely
different approaches to color management that are constantly intermixed.
1. Design in RGB, get the output profile to make visual adjustments,
stay in RGB and let the pixel conversion happen e.g. at the printers
output device.
or
2. get the output profile, make adjustments, get the correct pixel
values, discard the profile and supply the printer with the raw,
accurate, untagged pixel data. E.g. a 50%C, 50%M would print just like
that. No more profile needed and/or desired.
Or not?
Thanks,
Sincerely,
Arnold
On Thursday, October 31, 2002, at 07:27 AM, Shea Kelly wrote:
Hello Again.
You should always save an image tagged with a profile if it has one.
The
reason being;
1. You go to the effort of using a profiled environment and the
discard it
all why?.
2. The profile is a description of the image, should you need to
repurpose
the image the profile information will be invauable.
3. If you use the colour management polices in photoshop correctly the
image
will be displayed correctly regardless of your colour settings as
Photoshop
will use the embedded profile information to govern the display.
Hope this is of some use to you.
Regards
--
Shea Kelly.
Colour Quality Manager
News Stream Ltd.
t. 020 7782 4916
f. 020 7782 4949
From: Arnold <email@hidden>
Date: Wed, 30 Oct 2002 19:06:36 -0800
To: Shea Kelly <email@hidden>
Subject: Re: From Camera to printer
Hello and thanks for the reply again.
I am in Los Angeles, unfortunately slightly too far away from London
:)
but thanks for the invitation. I'd be there if it would be closer.
Second paragraph: oops, I indeed meant "convert to"
My final thought is now this:
Now that I indeed did change the pixels in the image by converting to
the target profile, do I still need that profile? Meaning, now that I
changed the actual pixels in the image to represent what I want it to
look like based on that "converted to" profile, do I still need to
have
that, or any profile be embedded?
I would think now that the pixels values are "correct", I could assign
the "don't color manage" "profile", thereby untagging the image. The
pixels values are the same after all, and it will not be looked at
anymore, but just printed out.
I have a feeling that even though this makes perfect sense logically,
I
am missing something here. If I leave a profile embedded, would that
be
reinterpreted by the output device? It shouldn't, as I already
converted to the correct profile before. It would seem redundant to
still have the image being tagged.
My HP inkjet example at home is one of two experiments I am doing. The
other one is at work with a Kodak Approval System and a Barco Rip. I
work in a prepress department and we now have encountered our first
customer who embedded a profile on purpose i his images.
His blue, is our purple, because his profile is not honored. :(
Sincerely,
Arnold
On Wednesday, October 30, 2002, at 08:24 AM, Shea Kelly wrote:
Hi Arnold
Just a few points.
In the second paragraph;
"Then you decide on the output device, get a profile for it, e.g. ink
jet, proofer, press etc., assign it to your image, thereby changing
the
pixel values to make them look like what you see on your screen will
come out of the target device."
You metion assigning a profile, at this stage you should be
converting
not
assigning.
In the fourth paragraph;
"Now to verify, you use proof setup with the same target device
profile.
Should you see a difference here?"
You may see a slight shift in colour.
In the fifth paragraph you metion;
"Now last question. If you print now from Photoshop 7, the source
profile would now automatically be the one that was "converted to"
before. In my case here now my HP printer. The print space should now
be Profile: Same as Source, correct?"
This would seem logical. Without looking at your own set up I would
rather
not commit myself to saying yes.
Finally you mention;
"In the printer option dialog box I have something called "Automatic
Image Enhancement". That should probably be turned off I assume."
I would turn this option off. The whole point of working a profiled
environment, is to allow greater control and predictabilty to your
results.
Using any form of Automatic Image Enhancement should be avoided
unless
the
effect it is having on the image can be quantified/controlled. Also
any form
of proprietry image enhancement at the printer stage will effect your
abilty
to softproof your work.
Where are you based?. During December/January I will be hosting a few
seminars/workshops in central London on colour management for
photographers.
regards
--
Shea Kelly.
Colour Quality Manager
News Stream Ltd.
t. 020 7782 4916
f. 020 7782 4949
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