2 spot colour gradient overprint issue

[Adam Morley]

Hello, I'm experiencing an issue in Indesign 24 (Mac ) 

An object with a gradient with 2 different spot colours won't overprint. Attributes are of course set to overprint, overprint preview shows no overprint occuring and a test pdf shows no overprint when checking the file separations in acrobat.

it's also worth noting, if I do a gradient with 1 spot colour to a process colour overprint works normally. Is there an issue with 2 different spot colours in 1 gradient set to overprint?

Any help or advice on this would be greatfully appreciated.

Adam 

[Brad @ Roaring Mouse]

Is this an object created in InDesign? There's no reason to worry about overprint in that gradient, the two spot colours would separate accordingly.

Unless there's something else you're trying to accomplish. Can you show us what you're trying to do?

[Adam Morley]

Hi Brad,

Came across the issue when working in illustrator but it also happens in indesign either with object created inside indesign or brought in from illustrator.

The file doesn't seperate correctly accordingly to the overprint. 

[Brad @ Roaring Mouse · Accepted solution]

Okay, here's your issue. In the left one, with two spots, you are dealing with what's called Simple Overprint mode. This is how overprints were handled in the "olden days". You could overprint DIFFERENT colours, but not the same colour. Only one value can occupy a spot at any one time, and the one on top wins out. So your tint of 811 at a spot near the left overrides the darker value beneath it.

What you want to do instead is assign a Multiply Transparency effect to your heart object. this does more modern detailed calculations on the interaction between colours. Give that a shot instead.

[Adam Morley]

Of course! I didn't twig that I was trying to overprint the same spot! I knew I was missing something. Thanks Brad, really appreciated it.

Adam 

[Brad @ Roaring Mouse]

Yay!

[Jeffrey_Smith]

Have you tried setting the object (with gradient of 2 different spot colours) to multiple, instead of overprint?

[Adam Morley]

Cheers Jeffrey, going to give that a go.