I think his questions is a bit more in-depth like (how do I get a new element into a current CMYK sep and create a new spot color that prints out with the other seps with my current registration marks).
So I think the answer is more about "separation methods" and combining.
For example,
1, I would open my vector program of choice, make sure it's at a close size to where I want it, since I don't want to scale or play with sizing too drastically in photoshop. I COPY that from vector, (so that it's copied to my clip board). Then, don't paste anywhere yet.
2, I move into my photoshop file. before pasting, I can do one fo two things. I can paste into a new RGB layer (if I want to keep it the vector "color") and use it for mock ups or something. I will sometimes paste into the RGB file I am working from and position, and then use it as a selection tool.
3, The other option is to paste into a new channel. In Channels, it's greyscale, so you don't get to re-size things easily there and when it's pasted, it's pasted in it's greyscale equivalent. So a Red, is pasted in as grey. IF you do this...and you want it to print as solid red, you then have to adjust levels or curves to slide the shadow tones to solid black.
4, To paste into a new channel, you first create the new channel. Go to top menu bar, go to windows and open channels window, where you will see your other spot (CMYK seps).
5, Go down to bottom and click on NEW channel icon (next to trash can) in that window.
6, Double click on this new channel to modify the settings of that channel. Give it a name if it's going to be a custom color or if you know the name (like pms 185 red). Here, I also put in the print sequence also. 4of5__pms195 red.
7, Click on SPOT COLOR. This enables you to output that separation (separately from any RGB or CMYK modes and becomes a (MULTI CHANNEL) file. Click the bottom left square for COLOR, and the color picker window pops up. Here, you can drag around the color window to pick a random custom color...or, you can now click on COLOR LIBRARIES to choose a specific Pantone color from the COLOR BOOK list. I use a couple different ones, but mostly I use the PANTONE SOLID COATED. Picking a color, (is more for a visual color assignment only in your file for that channel only). It does not change halftone percentage of color. It's a visual reference.
8, Make a selection of your registration marks or drag the selection marque over the registration marks and copy, from one channel into your new channel. Copy, then paste, should move it in the exact same location over top of each other.
Don't move the elements while you have them selected.
From here, you should be able to print that to film as a separate color. By using the new spot color (as a tool for selections), you can also add them into other separations to achieve creating that color with halftones of the other seps (if you want to reduce color count) for example. In this case, it gets more detailed since you want to know just how much to add where.
Print.
SIDE NOTE:
You could actually pick random pink color in the new spot color channel (color window) after you double click on it. Lets say you want to see the color sep (on screen abasing a white background but you are printing white ink on this sep. As you have the NAME of that sep correct, (telling the press person what color that seps is), such as TOP WHITE.
The sep still prints out the same even tho it looks magenta on screen (because it's a spot color). I use this on white inks for light backgrounds for example, so our screen person can see it in the RIP, since we do not send the production ready sep file (with the black shirt background color) as that would confuse them, and leave an added unnessasary element to the production file.
Leaving the shirt color in there, (not assigned as a spot color in the art), can also cause the RIP to assume the file is a RGB file...and also then converts the file to a CMYK file, added to your 7 spot colors. Causing even more confusion to the screen room. Avoid that and just delete your shirt color when sending your print ready file.
To add to any confusuion, (Some RIP's and outputting methods) like using a separation program...actually require the file to be a RGB file (with spot colors). Why, I dunno. It's in there program setup that way. I think maybe UltraSeps does it like this or one of the other sep programs. It confuses people when they receive a file from me that has nothing in it but the channel seps. Thats all you really need, but most don't know any other way other than what they ahh been doing or have been told to do. Some need it as RGB, Some need it as CMYK, and some just run it straight out of Photoshop as channel seps and some need them split up into individual files and some as a DCS2 single file, and some also need them converted to PDF, or tif, or, or. So at least, I get pretty versatile in file prep. LOL.
3 out of 10 new customers will email me and say "I can't get this to print right" and I go in to the many questions and find out they are printing via a separation program (even tho, I've already separated it),but thats how they print film. There are many many methods to print films for different options out there and I end up having to do workarounds or change my file up to meet their needs.
