RGB to CMYK - want to optimise colour

Karine R · **Joined:** Feb 12, 2013 **Posts:** 16

Hi Gimpers
I have some images that I need printed professionally.
Have saved them as jpg png eps pdf but as they are all in RGB I lose colour definition.
Blues and greens in particular become muddy. :gaah

As my brain is quite full & I am but a simple GIMP user - can anyone explain how I can convert the files to CMYK, retain my colours and not lose my hair at the same time!

Is there a plugin perhaps?

cheers
Karine R

K1TesseraEna · **Joined:** Sep 22, 2012 **Posts:** 2089 **Location:** US

There is Separate plugin for RGB to CMYK conversion http://registry.gimp.org/node/471
Works in GIMP 2.8.

Odinbc · **Posted:** Tue Feb 12, 2013 10:35 pm **(#3)**

Along with the Seperate+ suggestion have a look at this page, Help:Manual Toolsgimp for Gimp setup info. If your considering a professional printer, Scribus has the powerful tools you need for pre-press.
Export/Import capabilities of Scribus, OpenOffice, Inkscape, GIMP, and Krita

Karine R · **Joined:** Feb 12, 2013 **Posts:** 16

Thanks
Encountered a prob installing Seperate+
Windows kept asking for libtif3.dll
We found it in GIMP2.6 and then move it into the plugins folder for 2.8
good to go from there!

So I guess the next question is How to make the CMYK version look as good as the RGB. Any hints?
Seperate does split the image into 4 layers - one each for C M Y & K.
But d%$n the CM&Y are yucky colours. No wonder my lovely advertisement looks so uninspiring in CMYK. [it looks fabulous in RGB]. Any suggestions from anyone?

I might just resort to greyscale with a couple of colour washes.
How does anyone work with CMYK?

rich2005 · **Joined:** Mar 04, 2011 **Posts:** 2604

Quote:

..So I guess the next question is How to make the CMYK version look as good as the RGB. Any hints?..

Possibly the most consise answer is on the free www.rgb2cmyk.org site

Quote:

Question: I needed to convert to a CMYK format, I tried your online utility with the "default" (generic) conversion. My ordinary windows "photo and fax" viewer seems to make the resulting image look right again (as far as the HUE goes) on my monitor. But the colors sure seems to have lost their richness and vibrancy.
Is that just because the view is re-converting back to RGB to display it?

Answer: Some RGB colors that you can see on your monitor (in particular, blue, green and all bright vibrant colors) cannot be printed and/or replicated with standard CMYK inks. Keep in mind that, when creating a file for print, you should always make the original file in CMYK color mode before starting to work on it."

Gimp (and Inkscape) have plugins (extensions) to convert to cmyk but you will always be working in rgb up to that point
Scribus is useful to produce a cmyk image, especially in a pdf container but it is not an image editor.

The only free editors I know for sure that work in CMYK are linux Krita and the PSCS2 that escaped recently.

anarkhya · **Posted:** Wed Feb 13, 2013 9:28 am **(#6)**

rich2005 wrote:

[Keep in mind that, when creating a file for print, you should always make the original file in CMYK color mode before starting to work on it."

Yes, I'm afraid that's also the answer I keep stumbling upon.

Karine R · **Joined:** Feb 12, 2013 **Posts:** 16

So I have downloaded seperate+, installed the ICC files from Adobe.

I can separate the image [once flattened] into CMYK, but really can't do anything with from there.

I have found that GIMP now has a CMYK option in the colour tool, which I have used, but when I use the specific CMYK colours, and drop them into the region of the image that I want to reflect that colour... it appears that the image does not receive the colour I am dropping into it.
So then I found a CMYK colour chart, chose the colours closest to those I have used in RGB, and then used only the formulae that are in the CMYK picker in the colour tool. And again the image does not seem to receive that colour either.
I'm at a loss... All I get is the same dull murky olive green. Even tho the printers chart claims that the image should show the colour as per chart, and the colour tool shows the same colour too btw. But the image doesn't.
I have looked at Scribus, but the learning curve is a little steep, ad is due today. Also scribus doesn't allow for some aspects of manipulation I currently need.

So I guess the Q that is really on the top of my mind here is...is the colour printed by a CMYK print wysiwyg? or will my colour print as per chart?

PS I realised that my monitor is RGB, and to see my CMYK images I have to print them on my [CMYK] inkjet printer. But I still can't seem to get the colours as per chart that are supposed to print in CMYK. gaah!

Odinbc · **Posted:** Wed Feb 13, 2013 11:13 pm **(#8)**

Karine R wrote:

I have looked at Scribus, but the learning curve is a little steep, ad is due today. Also scribus doesn't allow for some aspects of manipulation I currently need.

Scribus is to Adobe InDesign as Gimp is to Photoshop.

You don't need to learn Scribus, simple export an .eps file of your work. In Scribus import the document. In Scribus, Window menu, select Preflight Verifier. If there are any pre-press problems with the document it will tell you what needs fixing.

anarkhya · **Posted:** Thu Mar 07, 2013 8:31 pm **(#9)**

May be interesting:
From inkscape to scribus, for CMYK color management stuffs, some steps to familiarize with the process: http://libregraphicsworld.org/blog/entr ... to-scribus