rgb to cmyk

[Todd Morgan]

CMYK is print plate related format. have you tried pantone?

[Adolf Witzeling]

The problem with RGB is that, in theory R+G+B printed on top of each other should give you BLACK. In reality that isn’t the case..all you would get is a dark brown mess, but not black….thats why printers print in cmy+K…to get the density and total black….that would be impossible to achieve in a RGB workflow.
There are different ways to achieve “vibrant colors”. One is called Hexachrome printing, which separates the colors differently, than cmyk. Printing in Hexachrome is more expensive than cmyk, but depending on what you are shooting for, might be well worth the extra cost. Some print houses are specialized in Hexachrome printing….search the internet for locations.
Another way to improve the colors, is to choose the right paper…..believe it or not….the right choice of paper for a certain job can Make or Break a print job. Uncoated paper usually soaks up the ink, and after it dries, the colors “muddy” down, because they soak into the fibers. Printing on coated stock brings out the colors a lot better, because the inks never really touch the”paper” but dries on the surface of the coating or finishing.
Another way to improve the colors is UV coating, or varnishing for example, where after the piece is printed it runs through the printing press again and will be coated with clear substrate, that really crunches up the colors. It’s also possible to “spot varnish” certain areas of a piece, to bring out certain colors or elements.
So there are quite a few ways to improve colors and make them vibrant……But of course all that assumes that you know what you are doing, before it goes to press…..
Color management is crucial…..Just looking at a RGB monitor with vibrant colors, and then converting to cmyk, won’t cut it…..Color profiles,monitor profiles, system profiles, Printing press profiles…..all that is neccesary to translate a good looking piece from a monitor, to a good looking piece on paper.
That should get you started…..
Take care.
Adi

[Mike Gondek]

Duratrans is a photographic process you should be sending RGB files directly to the Duratrans printer (EG Lambda). RGB will have a much wider gamut, and just wait till you see the blues. Most likely 300 dpi is the best quality for most Duratrans printers (eg Lambda).

For many types of printing such as lithography, you need to convert your files to CMYK for printing. Do you color balancing/corrections/sharpening in RGB though. Photographic processes such as Duratrans/slides are the exception which print from RGB files.

I have a feeling you are going to be very happy after you get your file back printed from RGB. I am actually not that far from Indianapolis so will be listening for a yahoooo!

[Darby Edelen]

[chris Newman] “isn’t cmyk a legacy color scheme?”

CMYK is a subtractive color system, which is how dyes and paints work: they subtract colors from white light. This is just the nature of printed material, white light (or close to it) shines on the material, in order for it to appear colored it must ‘subtract’ colors from the white light. Cyan subtracts Red and reflects Green and Blue, Magenta subtracts Green and reflects Blue and Red, Yellow subtracts Blue and reflects Red and Green. K is Black and is included because 100% C 100% M 100% Y theoretically results in black but in reality doesn’t (more like muddy brown).

RGB is an additive color system, it works with devices in which light is emitted to create colors (CRT, LCD, LED, anything emitting light)

[Mike Gondek]

Chris,

Did you ever get a chance to try an RGB file??? Wanting to make sure you recieved my post as it will make a world of difference.

[Chris Newman]

mike, we are working with a set company called FX and i’ve also talked to our local printers and unfortunately they both say that the image has to be converted to cmyk, even for duratrans. i want to investigate this further but it seems that anything print related must be cmyk (i think inkjet printers are an exception but i’m not sure about that). do you know of a company that will print things in RGB color space? if so, could you let me know who that is? i’d appreciate it.

ps. we even sent the duratrans to our set company in rgb just to see what they would do, not only could they not print it, but they had us convert it to cmyk (most print houses will do that conversion for us).

thanks
chris

[Adolf Witzeling]

If you deliver an RGB file to the print house, you HAVE to honor color managment in your file….meaning you have to deliver the color profile that you used in your system……
In commercial printing there is NO RGB printing press….thats why you have to include color profiles, so the conversion to cmyk can be controlled better.
Adi

[Adolf Witzeling]

forgot to mention, that high end inkjets are 4,5,6,7 and more colors, but they are NOT RGB colors. The print with cyan, magenta, yellow, black, light cyan, light magenta, light black etc.
So even if you send an RGB file it will ALWAYS converted to cmyk ( either on the rip, or on the printer).
There is no RGB printing environment.