Overprint or Transparency

[Yitz_Woolf@adobeforums.com]

I am working with a two colour document and I would like to add 15% of one colour to the other colour to darken it.

Should I set the attributes of the 15% layer to 'overprint' or should I set it to multiply? Will that convert it to CMYK?

Yitz

[Clay_Fowler@adobeforums.com]

When working with spot colors, it is usually preferable to overprint. You probably could get away with a transparency, I'm not sure about the CMYK issue, someone else smarter than I would have to address that one. However, I do know that a transparency would produce some sort of fine screen to simulate the change in colors, and an overprint will be much easier for the press operator to register and keep registered through the print run. (ESPECIALLY if you take it to a smaller local printer..)

You can always test how ID is going to treat separations by exporting a PDF and using the separation preview tool in Acrobat.

Hope that helps.

Clay

[Bob_Levine]

What version of InDesign? ID CS allows you to mix the inks to create a
new color swatch.

Bob

[Steve_Werner@adobeforums.com]

Robert is correct. If you have InDesign CS, you want to use the New Mixed Ink Swatch command on the Swatches palette menu.

[John_Slate@adobeforums.com]

FYI the mixed ink option, just like the older multi-ink option in QXP, does not work in many (most?) composite workflows, so if you are sending such work to a printer with a composite workflow, it would be nice to red-flag what you have done.

Otherwise, they will figure it out...eventually.

Same goes with overprinting.

Many composite workflows will ignore postscript overprint commands unless configured to do so, so redflagging overprints is also a proactive approach

Multiply and Normal are the 2 blending modes which are supposedly acceptable for spot color work, though I can't vouch for how multiply will work through all workflows.