Photoshop trapping: fast way to clone edge of CMYK elements OUT to create trap

[Jim_At...@adobeforums.com]

I've got a packaging job that has a flat expanse of a spot colour with smaller CMYK elements floating over the top.

I've made the spot channel, knocking through the spot channel where I need the CMYK elements to sit. Obviously I need to create a trap.

I don't want to use the Photoshop Trap function on these files, because that seems to SPREAD the spot channel over the CMYK elements, and it'll impinge on the CMYK elements too much, visibly reducing their size.

What I need to do is clone the edge pixels of the CMYK elements OUT to create my trap, but I'm wondering if there's a fast way to do it that doesn't require me manually cloning the edge.

I suppose I'm trying to replicate the "offset path" function in illustrator.

Ideas?

- Also tried duping the layers and just transforming them, but it obviously doesn't uniformly spread the edge.

[christoph_pf...@adobeforums.com]

Sometimes, obviously depending on the image in question or the part thereof, applying Filter – Other – Minimum to a duplicate of the layer and then soft-masking it to spread into the original image only a little has helped me.
Adding a little noise or applying a Pattern Overlay to match the original’s grain seems advisable.

[J_Ma...@adobeforums.com]

Make the spot channel a very dark color (Pantone process K would be good). Then the CMYk elements should spread. Once trapped, revert the spot channel back to spot x.

[Buko]

You can set the trap to any pixel amount you want.

[Jim_At...@adobeforums.com]

Massive thanks to christoph pfaffenbichler & J Maloney.

Both those solutions work really well with a small amount of tweaking.

Saved me A LOT of hours.