RGB vs CMYK 2

[annconroy]

For PC:

I have just traded up to InDesign CS4 and notice that a 'preflight' does consider RGB an error. I have to be sure that everything I have is in CMYK (for press). Does anyone know what's going on with this?

Thanks in advance!

 

[spamjim]

What is the problem? If everything is supposed to be CMYK, it should alert you on RGB objects.

If you are using PDF export, InDesign can automatically convert RGB to CMYK on some PDF profiles.

 

[apepp]

...the preflight panel is new to CS4, whereby you can define profiles and various options can be enabled, at the bottom of a document window is a flyout arrow, in that list is "define profiles"...

...here you can set up what areas you want to check for...

...the "basic" profile doesn't check for much by default, but having too many can slow indesign down...

...when you file > package, indesign also preflights much the same way that CS3 functioned, so even though the "preflight" panel may not be checking for RGB (by default), the package function does...

andrew

 

[annconroy]

Hi Andrew:

I set up the profile to check for colour, as you suggested. It worked, but I'm getting CYMK as an error instead of the RGB. Of course this is the opposite of what I want. Is there a way to reverse it?

Ann

 

[apepp]

hi ann,

in the define profile dialog, did you just click on the color checkbox or have you also expanded the "color" option via the arrow, left of the name "color"?

...just clicking on the color checkbox enables all the other subcategories within "color"...

...ensure you DON'T have the option "cyan, magenta or yellow plates not allowed"...

...also ensure you have the right custom profile enabled in the preflight palette...

andrew

 

[apepp]

...essentially if you "expand" the "color" category in defining profiles, you have more options, particularly you need to use "color spaces and modes not allowed", expanding that category allows you to choose "RGB"...

andrew

 

[apepp]

...if you wish, you can download mine here:

http://www.zen63258.zen.co.uk/tek/apepp IDCS4 preflight.idpp.zip

...this can be loaded via the "define profiles" dialog, left side at the bottom is a flyout menu...

andrew

 

[annconroy]

I got it!!! What would I do without you Andrew.

MANY THANKS.

Ann

 

[blueark]

A few years ago, someone told me that the whole RGB vs CMYK for print issue was a thing of the past. After 14 years in prepress, I found that difficult to accept, but now I find myself agreeing with them, and practice it daily.

Keeping an image in RGB (or LAB for that matter) retains a wider color gamut, and using the proofing tools in CS means there's no nasty surprises in print. This workflow also makes the most of whatever color profile your printer uses, because some printers have a wider gamut than others. Leaving things in RGB means you can decide on the most suitable color profile at the very last minute (e.g., when you export to PDF). Converting images to CMYK earlier in the process may mean missing out on printers with a wider gamut later on.

Getting back to the original post, with the above in mind, I actually find it really irritating to get RGB errors in preflight, as I don't consider them to be a real issue (although admittedly, I only really use preflight for copying jobs in-house; final artwork is always PDF). However, it is still a controversial work practice, though one I can certainly vouch for if you know what you're doing.

 

[annconroy]

A few years ago my printer said all colours have to be in CYMK, but I will look into this to see if things have changed with them.

Thank you for the information - very informative.

Ann

 

[blueark]

Ultimately, they do still have to be CMYK. For example, if I export a file as a PDF for print, it will use a suitable CMYK color profile as specified by the printer (or a generic one if the printer has no idea what a color profile is!).

The difference is that I don't bother converting all the placed RGB images to CMYK anymore, as that's handled by the PDF conversion. Even printing directly from InDesign files is fine, as long as the color settings are set up correctly. But you do have to ensure that the color settings are synchronized between CS apps (Edit > Color Settings), and do make sure that you make use of the View > Proof Colors menu item.

It used to be the case that you'd have your 'Master' images, with layers etc, then you'd flatten them and convert them to CMYK before placing them into a document, in case they'd cause problems with your layout software or printer. Any changes meant going back to the original, and repeating the process each time. I find it's much easier now to just work with the original image only, and leave the color conversions and flattening (if required) to InDesign.

 

[apepp]

...as blueark states, there are pros to using rgb colors, but there are also cons, color management is a big area and is only any good with accurate and high quality profiles. In some cases simply converting to cmyk from rgb can have colors go whacky, and depending on how color critical a job is, you have to then adjust the image in a cmyk space, like blues turning purple etc...

...just depends on what your dealing with, but i certainly wouldn't be creating text or vector graphics in RGB colors, if i wanted text to be 100K ink then i would make it so rather than picking a screen black RGB mix...

...bitmap images are different beast, and for sure RGB has advantages here early in the workflow...

...essentially from a prepress point of view, two images the same with different source RGB profiles converting to the same cmyk destination means you get a different color image. This can be a problem in a "re-print" scenario unless you have strict colour policies in prepress for all users...

...without a closed loop you have clients wandering why their reprints are coming out different, potentially a nasty/expensive situation...

...and on the other hand, no two print providers print the same in reality, using different systems, inks, papers etc...

andrew