B4Print.com

Have no doubt something will be achievable in PhSh, but my skill/experience does not extend too far yet. Was thinking that if you have PitStop Pro, and you've got that far, you can add a PDF to a PDF. I've used this for proofing purposes for overlay varnishes etc., but can't see why you couldn't use it for your task.
You can use Inspector to adjust Transparency mode, after the combining. A left-field possibility, is all, but in theory you should be able to end up with a single PDF, with the desired Spot Colours.

I'm a little unsure about a couple of things you're trying to do there, peaceflaps; I'd rather defer to a seasoned PhSh vet...along soon, I'm sure. Some stuff needs to be clarified, but the right questions need to be asked. A bit outside my comfort zone at present.
Pitstop is a plugin for Acrobat; rather than a standalone app.   v7 upwards supported PDF-in-PDF placement.

I'm not really clear and what you are starting with and where you are wanting to end up. You said you were supplied a PDF originally so is the part that is in question a vector image or a raster image in the PDF. Maybe post of a screen shot of the original and explain what colors that are CMYK need to be what spot color? Does the file end up needing to be just 2 spot colors, 1 spot and black, or 2 spots and black?

Okay, to merge the black and yellow you can use "Apply Image" under the "Image" menu. First click your target color in the channels pallet so only that separation is showing, for example the black. Then open "Apply Image" and the black will already be selected as the target color. For the source color select the Yellow from the drop down list. Change blending to multiply and opacity to 100%. This will merge the yellow and black channel into the black channel. You can do this multiple times if needed to make the target 100% for your spot separation. It won't delete the image from the yellow channel so you will have to manually get rid if it.

Do the same for the CM image. Now you have two separate images with your two spot channels. Once again you can use "Apply Image" to merge channels from one image to the other by selecting the channel for you target in the channels pallet and opening "Apply Image" and selecting your source image and the source channel.

Here is the example images I used. There is a CMYK image I started with and the finished image which ends up being CMYK + PMS Green. There is nothing in the CMY channel though so basically it is only using the black and spot green and it's still a tif file.

Attached Example images

ETA: There are other ways to accomplish this as well. This is just one way.

excellent - sounds just what i'm looking to do. i'll have to check the attachment in the morning (safari can't download them on an ipod touch unfortunately)

be sure to be on hand in case google is able to spell the rest out for me lol




am i right in thinking you can apply a channel from another file? sure thats how i did stuff before layers came on the scene.

Yes, you can apply channels from another file as long as you have it open in Photoshop. See my comments about "Apply Image".

UPDATE! :)


created a spot colour alpha channel and copied and pasted the black plate onto that - seems to look ok, apart from having a grey cast on the background of the black sep (but this is probably because i adjusted the brightness/contrast a bit before merging)

gonna have another look at it later when i get chance - please let me know if i'm doing it wrong :D

yeah, after playing about and finding my feet a little, i see what you mean.
went into a bit of a panic about it for nothing really, it all came back to me eventually lol. got the samples of the finshed job today and they were spot on (hehehe).


ta :)