CMYK query

L
Posted By
Livewire
Jan 7, 2005
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298
Replies
3
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Closed
A silly query perhaps, but . . .

If I send a DTP file to a professional printer I need to convert all images to CMYK or there’ll be a colour disaster.

If I print the same thing on an inkjet or colour laser — both of which use CMYK ink cartridges — my document’s images print fine as RGB, CMYK or a mixture on the same page.

Why can’t that work for professional print jobs?
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S
steggy
Jan 7, 2005
Livewire wrote:
A silly query perhaps, but . . .

If I send a DTP file to a professional printer I need to convert all images to CMYK or there’ll be a colour disaster.

If I print the same thing on an inkjet or colour laser — both of which use CMYK ink cartridges — my document’s images print fine as RGB, CMYK or a mixture on the same page.

Why can’t that work for professional print jobs?

Because the professional print shop uses films/plates for the 4 colors, not cartridges:)

steg
A
arrooke
Jan 7, 2005
A silly query perhaps, but . . .

If I send a DTP file to a professional printer I need to convert all images to CMYK or there’ll be a colour disaster.

If I print the same thing on an inkjet or colour laser — both of which use CMYK ink cartridges — my document’s images print fine as RGB, CMYK or a mixture on the same page.

Why can’t that work for professional print jobs?

To expand on Steggy’s answer a bit.
There is no such thing as a RGB printing press. Presses use either solid spot colour inks, or process colour inks (CMYK) – through which the colour spectrum is achieved.
If however, you are sending the files to be output, not on a press, but on a digital copier, such as a colour Xerox, then RGB often retains colour accuracy a little better than CMYK. Particularly the blues. If you do this, and you also have black text on the page; after converting to RGB you should re-spec the text to a true black. Otherwise the text will become a dark colour made up only of RGB with no black and look washed out. Confused yet?

Keith.
R
RicSeyler
Jan 7, 2005
And his output on his inkjet won’t look proper after it’s converted to CMYK. 😉

_arrooke wrote:

A silly query perhaps, but . . .

If I send a DTP file to a professional printer I need to convert all images to CMYK or there’ll be a colour disaster.

If I print the same thing on an inkjet or colour laser — both of which use CMYK ink cartridges — my document’s images print fine as RGB, CMYK or a mixture on the same page.

Why can’t that work for professional print jobs?

To expand on Steggy’s answer a bit.
There is no such thing as a RGB printing press. Presses use either solid spot colour inks, or process colour inks (CMYK) – through which the colour spectrum is achieved.
If however, you are sending the files to be output, not on a press, but on a digital copier, such as a colour Xerox, then RGB often retains colour accuracy a little better than CMYK. Particularly the blues. If you do this, and you also have black text on the page; after converting to RGB you should re-spec the text to a true black. Otherwise the text will become a dark colour made up only of RGB with no black and look washed out. Confused yet?

Keith.

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Ric Seyler

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