CMYK is the only color mode you should be using for typical offset printing. Those are the primary colors for printing and therefore are the colors in a press. RGB are the primary colors in video monitors--totally different world. There are other forms of offset printing including hexachrome and hi-fi, but that's irrelevant to what you're asking.
Rgb images can be printed by the newer digital copy machines, but you may be surprised with the outcome. If you are offset printing the images must be in cmyk mode to print correctly.
If you're printing the image on your desktop printer, use RGB--those printers will convert anything else to RGB, then to CMYK. If you're printing it on a wide-format inkjet printer like a Roland, Mutoh or VUtek, or you're sending it to a printing plant to be printed on an offset or flexo press, use CMYK if you're not using spot colors, and Pantone for the spot colors.
RGB has a larger gamut than CMYK. In order from small to large: sRGB, AdobeRGB, ProPhoto RGB. The largest of the CMYK gamut is GRACoL.
The underlying color model in Photoshop is neither RGB nor CMYK but LAB. It has the widest gamut, which means it can hold more color values than any other model. Of the two other models, RGB has more color values than CMYK does. When you convert from RGB to CMYK, the program first "maps" the RGB values into the LAB colorspace. It then maps the LAB values into the CMYK colorspace. Now, for REAL entertainment...take a pure RGB blue, or a pure RGB green, and attempt to map it into CMYK colorspace. It doesn't work at all. Red maps fine, but the other two go straight to hell.
You can not. Rgb is a light mixture mode, and only useful for display on a monitor or online. To specify a color name for printing you must use the Pantone color matching library or the cmyk mode which simulates full color printing.
Rgb images can be printed by the newer digital copy machines, but you may be surprised with the outcome. If you are offset printing the images must be in cmyk mode to print correctly.
If you're printing the image on your desktop printer, use RGB--those printers will convert anything else to RGB, then to CMYK. If you're printing it on a wide-format inkjet printer like a Roland, Mutoh or VUtek, or you're sending it to a printing plant to be printed on an offset or flexo press, use CMYK if you're not using spot colors, and Pantone for the spot colors.
go to Tools > Commercial Printing Tools > Color Printing... and select what you want.
For web designs you would you an RGB color format. For things like poster printing you would use CMYK. Also CMYK is the typical printing process used for production.
RGB has a larger gamut than CMYK. In order from small to large: sRGB, AdobeRGB, ProPhoto RGB. The largest of the CMYK gamut is GRACoL.
neither
ensure that you use the cmyk option from the start of your design, and that illustrator does not default to rgb. Try printing in rgb if the colors brighten up there is a good possibility you created the large format design in rgb. rgb for webstuff and cmky for printstuff from the very beginning!
The underlying color model in Photoshop is neither RGB nor CMYK but LAB. It has the widest gamut, which means it can hold more color values than any other model. Of the two other models, RGB has more color values than CMYK does. When you convert from RGB to CMYK, the program first "maps" the RGB values into the LAB colorspace. It then maps the LAB values into the CMYK colorspace. Now, for REAL entertainment...take a pure RGB blue, or a pure RGB green, and attempt to map it into CMYK colorspace. It doesn't work at all. Red maps fine, but the other two go straight to hell.
You can not. Rgb is a light mixture mode, and only useful for display on a monitor or online. To specify a color name for printing you must use the Pantone color matching library or the cmyk mode which simulates full color printing.
go buy RGB cartridges
RGB is specifially suited to computer screens or televisions, it is not for printing.
RGB is usually the best and has the widest variety of colors