Re: How to get those colours outside RGB!
Re: How to get those colours outside RGB!
- Subject: Re: How to get those colours outside RGB!
- From: email@hidden
- Date: Mon, 8 Jul 2002 10:44:17 EDT
In a message dated 7/7/02 3:20:41 PM, Tvr28 writes:
>
For the use i have in mind, I will be printing colour swatches (not images)
>
so potentially a number will be outside RGB colour space. I'm using
Photoshop
>
6 at the moment and when you open a new template you ahve the opotion ogf
>
RGB, CYMK, Lab file format. presumebaly if select teh L:ab format i will
>
retain the information on colour outsuide RGB, but as soon as i print this,
>
data is converted to RGB, and hence truncated? Unless its sent to a RIp
>
whcih interprets this Lab data? (or am i getting this all wrong!?)
If you use a RIP with named color callouts to spec spot colors, and the
necessary swatch libraries, then you can get accurate color from PostScript
files simply by giving the color the right name (which selecting it from the
swatch library will do), so that the CMYK numbers involved are of no
concequence, as they are discarded and the LabValue-to-DeviceProfile for that
color used instead. Short of a good RIP with named color callout capability
and the libraries involved, your luck at getting spot color to print as you
want them to will be more limited, and more difficult. Yes, you could spec
them in Lab, if you knew the Lab values for them (Lab values for swatch
libraries not always available in a direct manner) and then use an output
profile to print from there... but that may still be one step short of what
you need if you are not printing final color to your device, but proofing
what will be seen on a press instead, and will require an accurate
DeviceProfile either way.
If you don't have a RIP at all, and wish to print RGB color, then you need to
be sure that your RGB color is not being changed or "improved" for you by
settings in the driver or software, and then print with an RGB device profile
from WorkingspaceRGB to DeviceRGB (using an accurate profile for the
device)... and use WorkingspaceRGB definitions for your swatches in the file.
Again, this is not press proofing, but direct output swatch matching that is
being described.
C. David Tobie
Design Cooperative
email@hidden
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