Posted: Thu Feb 18, 2010 10:57 pm Post subject: Process printing without black? (CMY with no K?)
I've just been informed that the process used to print the food packaging tubes that I am working on DOESN'T use black!
Thus leaving me with the C,M and Y channels. Now, I could very easily remove the black channel of my images in the Channels palette in PShop - which of course will impact upon the tonal range of my images.
Is there some way that I can convert the images from either RGB or CMYK to CMY - whilst retaining/approximating the darker tones using only three channels?
I'd really appreciate some help here - I'm lost. I've had a bit of reading online and the only info that I can find relates to inket printers and such.
I have a hunch that this is something that has to be adjusted in the Pshop colour profiles - by setting the GCR value to 'no black'?
Is this right?
I tried doing this, setting up a custom CMYK profile - and when I reopened my file there was no black in the black channel and the image retained its tonality to some extent.
HOWEVER, every other image that I opened in photoshop also had no black in its channel - so I obviously changed a global setting on the program. I then changed it back so that Pshop would work with embedded colour profiles when opening images, cause I realised I'd screwed up and didn't want ALL of my images without black.
I know the fix is something to do with colour profiles - but I'm really scared of screwing up my colour management by tinkering with colour profiles - since it is not my area of expertise.
Can someone please point me in the right direction so that I can apply this colour profile ONLY to certain images, without ruining all of the images I edit in the future because I've applied the profile incorrectly?
Really appreciate this - I am totally out of my depth here. Damn cheap-skate clients printing in China!!! If only I could speak with the printer!!!
gnr8r
I threw this topic out to my "old timer" colleagues, because I have no real knowledge of flexo or package printing. They do. Mind you, these guys haven't done this type of work in awhile, but they remember all too well the challenges and complexities involved.
After the laughing subsided, they informed me that you not only don't have a black, but you probably won't have C, M, and Y either!
Once you find out from your printer what spot colors they're printing with, you can save your CMYK (tif, eps, etc.) to a DCS 2.0. You then add the spot channels of those inks, display the individual channel, and copy/paste your cyan into a Reflex Blue, for example. Display the magenta and copy/paste into a Rhodamine Red channel, etc.
Once you're done "tweaking" those spot colors to match the CMYK, (as best you can), you can delete the CMYK separations and save the DCS 2.0. That file is sent to your printer.
Oh yeah. One last thing. They all said to finish by saying GOOD LUCK.
Also. I didn't want to scare you but you may also need to supply a white K/O for these colors to print on cardboard, foil, etc. Ouch.
For funzies, grab a cereal box and look at the color bars or targets inside the flaps. Sometimes you get to see what's involved, just like a toy surprise!
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