RGB or CMYK in print?

[dleather]

Originally Posted by gordo

It would be an interesting exercise to take a RAW image straight out of the camera and have some of the prepress folks on this forum do their massaging of the image as if it was a live job and compare the differences in final work. I'd be happy to supply one if there is interest.

best, gordon p

That would be interesting. Our prepress provider usually gets the Raw image, the .plist file, and a low res JPG from the photographer as guidance for focus, white balance, color settings etc. (Our end result is color matched to specific fabric swatches, so what the camera captures always gets changed anyway...) A quick screen shot, or low res JPG of the "desired" result could help here too.

[Stephen Marsh]

dleather wrote:

> That would be interesting. Our prepress provider usually gets the Raw
> image, the .plist file, and a low res JPG from the photographer as
> guidance for focus, white balance, color settings etc.

Just curious, but what (Mac) raw converter are you using that imports
settings via a PLIST file? Adobe products usually use .xmp, so I am
presuming that you use another converter?

Stephen Marsh

[graficworx]

Everyone has had some great discussions on how to get the files, but it's equally as important to how you send the files to press. Any printer or press on the market uses CMYK natively. None use RGB, as RGB is a subtractive color profile (subtracts from black) and CMYK is additive color (adds to white). If you sent a press operator an RGB file they may reject it, or convert it. If they convert it themselves it will not look like how you saw it.

If you convert it to CMYK yourself and you have the correct color profiles for the output device it should look the same on almost all output devices from inkjet to offset press and everything in between. Of course there will be slight color variations that's unavoidable.

300 dpi at full size is usually accepted as the industry norm. That should be sufficient for any output, and is fine for offset press or laser output.

[gordo]

Originally Posted by Stephen Marsh

Count me in!

I would suggest that we all agree, or that Gordo stipulates a common colour space (say either sRGB or a specific ISO CMYK) and also a common resolution in pixels and a format such as JPEG (I guess it depends if the results will be viewed in a browswer, or say a PDF or PSD etc).

It would also help if Gordo gave some sort of "brief" to describe the intent of the rendering - or just give us all freedom to do what we wish without "customer creative direction".

Stephen Marsh

Dang, looks like I've got some work to do. Like think and take a photo. I'll do that tomorrow.

It probably should be some kind of product photo rather than something arsty.
Perhaps the RAW image should be prepared for the web (I'll spec the pixel dimension so that they can be displayed in a forum's post or somewhere else) so that'll be sRGB and for the CMYK it probably should be targeted for a "magazine ad" rather than a color space since, unlike prepress folks and color gurus, that's probably what the typical designer is thinking.
If that makes sense, I'll post the RAW image (15mb) and provide a download link tomorrow.

best, gordon p

[Lukas Engqvist]

Just to have it compared on the web means we all will go to sRGB, and that will be the weakest link. Whatever extra you can get out of camera Raw to make it a superduper print, will be lost when you convert that to sRGB to display for "comparison" Next we'll be comparing racecars stats in the parking lot of the local mall?

[gordo]

Originally Posted by Lukas Engqvist

Just to have it compared on the web means we all will go to sRGB, and that will be the weakest link. Whatever extra you can get out of camera Raw to make it a superduper print, will be lost when you convert that to sRGB to display for "comparison" Next we'll be comparing racecars stats in the parkinglot of the local mall?

Hmmm, maybe I'm wrong, but sRGB should allow people to compare the images on the web - but sRGB doesn't have to be used for the CMYK version.

Or, what would you suggest to do?

gordon p

[mattbeals]

Here's another kooky idea...

Gordon selects an image, maybe some sort of "standard" RGB test image we're all familiar with and puts it on a test form with an output intent (a la PDF/X-3) of say SWOP2006 3v2 or FOGRA39. I don't know, some standard profile we all have. Then we use our respective RIP's to convert the RGB data in the PDF/X-3 to CMYK.

That may be more to the point of where the conversation should be going. As I said, we have some sort of "standardized", at least we agree on what image and color space, image that an advertiser may use in multiple ads going to different print providers. Send it as a PDF/X-3 and see what RIPs would do with the RGB to CMYK conversion. This comes close to the idea of a "digital master" that print providers need to convert for printing.

Would this not address Sannysmith's original questions of:

Hope makes sense as I really have no idea how print publication works. The photographs would go in various print magazines,brochures, etc.

1) Since I am new to the world of print publication I wanted to know if a RGB at 300dpi or CMYK at 300dpi photograph is advisable.

2) Also when giving instructions to a professional photographer what all should I mention that I need a high res tiff file. Is that the best format to use for print?

The RAW exercise is definitely an interesting one but may be going off track. I think a few people have made a valid point that RGB is more likely to be the "original" color space provided to the advertiser. It's a reasonable baseline assumption for many real world situations. The advertiser/content provider composes a page and submits it for production. Let's all assume it's SWOP 2006 3v2 for schlitz and giggles. What does Apogee do with an X-3? What does Prinergy, RAMPage, Harlequin, etc do? We all can get a color managed bitmap or PDF out of our workflows that reflects the conversion process. We can then collect all the results and and make some sort of comparative analysis. This might actually provide real world, meaningful results to not only ourselves but the rest of the print community. The ultimate question may be "can a late binding color managed workflow provide acceptable results?"

[meddington]

Originally Posted by mattbeals

The RAW exercise is definitely an interesting one but may be going off track. I think a few people have made a valid point that RGB is more likely to be the "original" color space provided to the advertiser. It's a reasonable baseline assumption for many real world situations. The advertiser/content provider composes a page and submits it for production. Let's all assume it's SWOP 2006 3v2 for schlitz and giggles. What does Apogee do with an X-3? What does Prinergy, RAMPage, Harlequin, etc do? We all can get a color managed bitmap or PDF out of our workflows that reflects the conversion process. We can then collect all the results and and make some sort of comparative analysis. This might actually provide real world, meaningful results to not only ourselves but the rest of the print community. The ultimate question may be "can a late binding color managed workflow provide acceptable results?"

This would be an interesting endevour (actually wondering if there has aleady been something similar formally done), but for different reasons than the test gordo suggested. In comparing RAW image processing, you're really comparing how a live operator is interpreting how the image should look...a subjective analysis of how the scene should be interpreted.
The test you suggested is essentially comparing how color management is applied via processing a PDFx-3. This would require a much more objective analysis as the differences should be limited to conversion settings at the rip, CMM choice, rendering intent, gamut mapping characteristics of the profile (which has nothing to do with the Workflow itself), etc. You'd likely want a much more objective analysis of the results...Colorimetric analysis of it8.7/4 chart for example. The altona suite would be a decent choice for this type of test. But because the differences in gamut mapping are due to the icc profile and the software that generated it, the results you get might not be conclusive ,unless perhaps by mandating a specific icc profile (rather than characterization data), rendering and CMM. Even then, if someone chooses to use their own profile generated from the charsterization data, the results may vary, but this could not be considered truly deviant.
Of course this only tests the suggested PDFX-3, which is only one option., and debatable how "real world" this actually is. How many printers out there actually receive PDFx-3 files, compared to say x1-a, or other flavor?

[John Clifford]

Originally Posted by michaelejahn

Hi John,
PDF/X-1a can indeed contain color profile information - and often does - and as a PDF/X-1a PDF file requires an output intent (which is itself a ICC Color Profile) - well...

Micheal,

Great to cross swords with you again. I believe that the PDF/X-1a spec disallows any ICC profiles from being attached to a file. This was the major difference between X-1a and X-3 (I remember Stefan Jaeggi at Seybold's railing about we backward North American's with our unwillingness to accept color management -- or something like that). Thus my comment. X-1a requires conversion to CMYK and does allow for output intent, but not color management.

From the PDF/X-1a standards: PDF/X-1a is designed to provide the most robust and, to some extent, least flexible delivery of PDF content data. It requires that the color of all objects be expressed in CMYK or spot colors, prepared for the intended printing conditions. Elements in RGB or Lab color spaces OR TAGGED WITH ICC PROFILES ARE PROHIBITED. It also requires that all fonts used in the job be embedded in the supplied PDF file.

[mattbeals]

To me the output intent of a PDF/X-1a file expresses what color management has been done. That is, what color space the art has been converted to and simply communicates that to the recipient.