Re: RGB to CMYK
Re: RGB to CMYK
- Subject: Re: RGB to CMYK
- From: Marco Ugolini <email@hidden>
- Date: Sat, 03 Dec 2005 17:40:27 -0800
Denis Glickman wrote:
> The fact is that trying to have a color management is a pain because nor the
> client or the people who offstet print doesn't know anything about it.
Hi, Denis. You are right to say that it's a pain to deal with people who
want nothing to do with color management (CM), specially when they are on
the prepress end.
But, though that may be the case either occasionally or often, fact is that
without CM you would forced to deal with unknowns that are more daunting
still. No matter the undeniable difficulties (both in learning it and in
using it in the real world), CM it is still a great time-saver and precision
tool (within limits) for us as users and producers of "color content".
And that remains the case even when prepress and print people care not a
whit for it.
> They don't understand a word, and the client would like the final print look
> like what they see on my screens ...
Exactly: and your loyalty is to the client, not the prepress folks. The
trick, then, is to show the client only what is feasible, and not create
misleading expectations (for example, by giving them prints that are
unrealistic, or showing them image files on uncalibrated/unprofiled
displays, etc.).
> Up to now I could resist to go to CMYK, staying in RGB, but they were too
> many problems" after me" (all the people working after me) so I decided to buy
> An Epson 4800 printer and some proofing paper to have something going out from
> here that could look like CMYK print, because all the prints I was doing on my
> Epson R800 were "too good" and the final image was too far from that ...
That's a commendable step, and a difficult one to handle correctly at the
same time. Difficult because the "too good" prints from your previous inkjet
were not so much too gorgeous as arbitrary and not realistic. Meaning that
they did not reflect at all any standardized and proven process.
We definitely want to help end what is still standard practice in so many
design firms to this day, i.e., the habit of sending files to print from a
CPU that uses an uncharacterized and unprofiled display to an
uncharacterized and unprofiled inkjet or laser copier. That is what I define
as "anarchy" (hoping that nobody will object to my negative use of this
term).
Your new 4800 is the perfect tool for proofing. Now the hard part is for you
to manage it properly. Maybe you want to look at the option of adding a RIP
to it.
So, long story short, you made the right move buying an Epson 4800, and
ought to stick with it: keep plugging away at building a comprehensive
color-managed system, from your CPU/monitor all the way to your scanner and
inkjet printer.
> As i couldn't get any information from the men in charge of the offset print,
> was obliged to choose a standart CMYK, knowing it is a world i don't know at
> all ...
But you will know more and more about it as you keep going.
> Photoshop CS2 uses Fogra as defaut europe pre-press
> InDesign CS uses Euroscale coated v2 as defaut europe pre-press
> Previous Photoshop use euroscale ...
Photoshop CS2 allows you to synchronize your color settings centrally for
all the applications in the suite. So, no more variables of the sort you
mention: decide on one set of standards and then just worry about them no
more.
> If you are supposed to deliver CMYK and If you cannot get infos for the offset
> press, or the paper:
Then please do try asking someone else more qualified, before you give up:
often it's a sales representative that is talking to you, and he/she rarely
knows squat about prepress issues, though they may attempt to convey an
impression of knowledge and being-with-it.
> And you also know your images will be printed in different uses (catalogue and
> packaging, not by the same people...)
Then it's very unwise to provide more than one file, since it often leads to
chaos and fingerpointing (i.e., the other side pointing their fingers *at
you*).
> _ What is the safest CMYK to choose,
I would say the one for the highest-quality printing scenario that you are
able to predict is going to be used, also keeping in mind what Henk has
written in this forum about the evolving printing standards in Europe.
Once you provide that separated image file, the prepress people will have to
re-separate it themselves for all other lower-end applications.
And also, along with your CMYK file, provide the service bureau with your
own inkjet color proof, one that looks the same as what the client has
already seen and approved. (Warning: *this is not a contract proof* quite
yet: unless explicitly stated otherwise, that should happen only when the
service bureau sends the final laminated proof.)
> _ What settings for rendering would you use during conversion from Adobe RGB
> to CMYK
Try Perceptual and Relative Colorimetric (with Black Point Compensation
[BPC]). Often enough, RelCol works out very well, though sometimes it
creates visible banding or clipping in saturated tones (and in the shadows
if you don't use BPC).
Make color-managed proofs on your 4800 for these different conversions, and
inspect very closely what comes out. That should be a good starting point to
make any necessary adjustments in the file.
> _ What else to avoid problems ...
Well, there will still be problems, but hopefully less and less of them as
you keep developing your knowledge, skills and confidence.
Bonne chance!
--------------
Marco Ugolini
Mill Valley, CA
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