I am not really a print person, I normally work with video.. so this is a bit beyond me but here is my problem:
I am helping a friend update an edition of his book which contains hundreds of maps / charts. Its the 9th edition of the book so I have a mix of old and new charts, jpegs, tifs and vector ai files - all of which are black and white, with 1 spot colour (which is printed green).
The problem is in the older charts (non vector tifs and jpegs), they've just used the cyan layer or channel or what ever you call it, as the plate for the spot colour. So those charts are blue.
The new charts are vector ais and they're the correct green.
Is there a way for me to convert the cyan to a pantone green spot colour? Or should I convert the green layer in the new maps to blue and tell my friend not to worry, they'll print it green.
There's a couple ways you can do this. I think the easiest will be to simply move everything from the cyan channel to a new spot color channel, although there is nothing wrong with simply telling the printer to use a spot color for cyan, too.
Anyhow: I use the Print/Proof workspace to set it all up (Window >> Workspace >> Printing and proofing). You get the separation preview window there, too. Create your spot color (using the swatches palette, go to the drop down and pick Open swatch Library >> Color Books >> Pantone Solid Coated), find a likely green candidate and drag one of the swatches to an object's fill (one you will want that color). In the separation preview, you will now see that spot color listed. Now, select whatever is cyan - fill or stroke - go to Select >> Same >> ... from here, it depends on what you have as cyan, stroke or fill or both. Once selected, go to the swatches palette and your spot color should be there, you can drag it to your objects, etc. to change colors.
I kind of hazed through this since it sounded like you had a good grasp of Illustrator already. If you want more detailed instructions, just let me know.
And whilst I am glad my ruse worked.. my grasp of illustrator is indeed limited.
I'm in the print / proof workspace. I got me Pantone Green C in my swatch zone... but how do i select just the cyan? I can obviously turn off the YMK in the separations window when I have the overprint preview box checked. But as this is a flattened jpeg or tiff.. i can't work out how to actually select just the cyan objects. The whole rectangular outline of the whole jpeg is selected. Gah!
Thank you for your help.. this is a real doosie for me.. I have hundreds of maps to adjust. waah.
Okay if you are dealing with TIFFs or JPEGs, you are better off working in Photoshop. In PS, open your TIFF, make sure you are set to CMYK for your color mode, you may have to convert if not, but that may not work correctly. Anyhow, you can simply isolate the Cyan (C) channel in the channels palette, CMD-click (CTRL-click for PC) the channel to select it, then create a new channel, assign it a spot color, then paste the info to the new channel.
Can you post one of the files you are working with?