Here's why RGB will finally win the day.
The question is not whether a file will be converted; all color image files will ultimately get converted into some different color space. The conversion may be so subtle the human eye will not notice, but for rich, bright, saturated colors, the conversion is usually very noticeable.
In the past, print providers have insisted that designers convert their RGB files to CMYK. If the designer wants to keep his or her RGB images, that’s fine, but they were asked only to send the CMYK version for the actual printing process.
In any workflow, the final control over the color from the output device is ultimately directed by the RIP. So the modern approach is to build color management into the RIP itself. The method used for printing the most accurate and faithful color output is to have as much data coming in as possible. The operator (or more accurately, the color profiles created for each device) tells the RIP the limitations of each specific output device. This allows the RIP to select the precise data that will come as close as possible to matching output to input.
Other benefits, caveats, and limitations
Several advantages to RGB workflows exist beyond getting the best possible output for each given device.
Because you are not changing the data in the original file, the same file can be re-purposed for optimum color output for any other device. If, however, a file has been converted to CMYK for a web press, for example, you are forever stuck with that very limited color gamut.
This means that when you output the same file on your high-end wide-format printer, the results will significantly be of poorer quality than the device is actually capable of. Yes, you could pump up the colors by using a program like Photoshop, but if you do that, you are not going back to the original data (again, it’s gone for good)-rather, you are only able to artificially pump up colors, so it definitely won’t match the data of the original no matter how good your Photoshop technician is.
The same is true when you reproduce an image for the Web or any other type of output. Once you convert a file, the original data is lost.