Flattening transparency for print in Vectornation

Transparency is everywhere in modern artwork: soft drop shadows, blending modes, opacity masks, a semi transparent panel over a photo. On screen it all looks fine. Some printing systems and older file workflows cannot handle live transparency, though, and need artwork where every overlap has been worked out into plain, opaque pieces. That is flattening, and Vectornation by Zaweba has the tools to do it with control.

There are flattener presets, a Flattener preview at Window > Print and output > Flattener preview, and a Flatten transparency command.

What flattening does

When two objects overlap and the top one is partly see through, the colour you see in the overlap is a mix. Flattening calculates that mix and replaces the overlap with opaque pieces of the right colour. Where it can, it keeps the result as vector shapes. Where effects are too complex, such as soft shadows over a gradient, parts may become pixels.

The result looks the same but behaves differently. It is no longer live: change the opacity of the top object afterwards and nothing updates, because the overlap is now its own shape.

Presets

Flattening involves trade-offs between keeping vectors and turning areas into pixels, and between quality and file size. Presets bundle those choices so you do not have to make them afresh each time. A preset aimed at high quality print keeps more as vector and uses a high resolution for anything rasterised. A lighter one suits proofs and screen use.

If a printer gives you settings, make a preset to match and use it for their jobs.

The Flattener preview

Before you commit, look. The Flattener preview shows which parts of the artwork are affected by transparency, so you can see where flattening will make changes. Use it to spot trouble: text caught under a transparent object, which may flatten in a way that makes it look slightly heavier, or a large area that will become pixels when you expected vectors.

Often the fix is in the artwork, not the settings. Move text above a transparent shadow rather than under it, or simplify an effect that touches a large area.

When to flatten, and when not to

Do not flatten your working file. Flatten a copy, or let the output do it. Modern PDF workflows, including the PDF/X-4 export in Vectornation, keep transparency live, and most printers today prefer that.

Flatten when a printer or a process asks for it: an older RIP, a cutter or plotter workflow that ignores transparency, or an export format that has no idea what opacity is. In those cases flattening yourself, with a preset and a preview, beats leaving it to whatever the other end does by default.

Common transparency trouble

Small text and thin lines under transparency are the classic problem. After flattening, they can be split into pieces or rasterised at the edges, which shows up on press as a slight change in weight. Keep fine type on top.

Spot colours under transparency need care as well. Check the separations preview after flattening to see that spot inks are still where you expect them.

And keep an eye on file size. Flattening a complicated drawing can create many more pieces than the original had. If a flattened file is heavy, the preview usually shows which effect is responsible.