[theboyk]

Originally Posted by pixelzombie

so let me get this straight, you'd rather send a RGB file to the rip instead of a cmyk file?

If printing to any sort of inkjet based printer (which is pretty much what you'd be using if printing to a canvas) and you want to print the full color gamut of your image without restricting it to the limited gamut of CMYK, then yes, without a doubt you would want to send to the RIP as RGB and it would print using the entire RGB gamut (based on that printer type profile). Even if you're trying to proof the image as if it were going to be printed on a traditional CMYK press (offset, web, etc.), you'd send it as RGB and let the RIP simulate the CMYK printing (based on the CMYK press profile supplied by your printer). As soon as you convert your image to CMYK you've lost a massive amount of color data because of the limited CMYK gamut. Keep it in RGB.

And even if you were sending your files to a traditional printer (CMYK offset press, web press, etc.) if you're lucky and you have a good printer with a color managed workflow, you'll get the best results by leaving your images in RGB (again, based on their RGB working space/profile) and again let their RIP manage the conversion on the fly from RGB to CMYK (thus, never having to convert your image out of the RGB color space). If your printer doesn't have an RGB color managed workflow and you *have* to convert to CMYK, then you should, at the very least, get their CMYK press profile for converting your images. Otherwise, under most cases, your randomly converted CMYK profile will be ignored by their RIP and their working CMYK profile will be assigned (and this could result in an unwanted color shift in your image because color numbers are preserved rather than converted).

So, in short, whenever possible, stay in RGB. I know this sounds crazy because these days everyone thinks RGB is for the web and CMYK is for print, but that's just not true. RGB is the way to go whenever possible (and when you do have to convert to CMYK, ALWAYS keep a copy of your RGB original).

k.

[pixelzombie]

i've never heard anyone recommend sending an rgb file to a RIP unless you were sending it to an RGB output device...

[theboyk]

Wow, that's too bad. You should look into it.
k.

[pixelzombie]

i used to work for Schawk and i'm sure they know the proper way to send a file, but i will run a test when i get a chance...

[Alison]

Originally Posted by pixelzombie

so let me get this straight, you'd rather send a RGB file to the rip instead of a cmyk file?

Some boxes rip both RGB and CMYK. The calibration of the RIP will affect both in a different way.

The box changes all inputs to RGB, then does the calibration offsets and prints in CMYK.

CMYK is the standard for basic-grade colour printing (printing as in printing, rather than printing as in photography).

Send the files as RGB unless otherwise requested by the printer - it is a fallacy that all printers print in CMYK.

EDIT - Your photographic images are held in additive (RGB) form. The simple rule is that for all normal photographic printing purposes you should hand them to the printer driver or RIP as RGB and let it sort out how to use the inks at its disposal. Your control over that is through the colour management facilities in the software you are using. Do not try to do the CMYK conversion yourself. In any event, if you are using a modern printer it is not CMYK that you are converting to anyhow, but (in the Canon case) C.pC.M.pM.Y.R.G.K.

[Damo77]

In my situation, yes. I send RGB files to the printer, and if they don't print to my satisfaction, I demand reprints.

If I send CMYK files, I'm seen to be taking the conversion into my own hands, and therefore I'm responsible for the quality. I certainly don't need that, because at any time the printer could have changed their ink or media supplier, or some other factor out of my control.

[cheshirepoet]

The best CMYK profile imo is GracolG7. I find that it helps retain more vibrant colors and gives just a little kick of contrast to the image. I soft-proof in Photoshop then send an RGB file to RIP software and have it simulate the CMYK profile...for both proofing and personal printing.

[Leo]

Sorry, that I did´t unswer. I was out of town. I´m going to print on PLOTER HP 5500. And they want to recieve a file in CMYK.

[pixelzombie]

see if the manufacturer of the printer has any profiles on their site, i use the epson profiles on my epson inkjet and i am very happy with the results...