EPS merges part of layers, but some groups stay instact. Why?

[łukaszt19747315]

Hi

I have a project in AI with 4 main layer groups, and I need to resize it, and then save it as EPS while maintaining layers.

The problem is that when I do it 3 groups are rasterized to one flat image and 1 is left intact, and I can't figure out why it happens even tho I was able to do it before.

I've tested this AI in different Illustrator version to see if it's an issue with the program itself, but all versions give me exactly the same result, so it's looks like it's a file issue.

Any ideas what can cause EPS to merge some layers and some leave intact? 

Ps. Yes, I know that EPS is old and so on, but some but e.g., ShutterStock only accepts EPS for vector projects.

[Monika Gause]

EPS cannot keep transparency. So if you use transparency in your artwork, it will be flattened.

[łukaszt19747315 · Accepted solution]

EPS can keep both layers and transparency in e.g. Ai, but if you open that EPS in e.g. Ps, then it will rasterize the whole project.

-- SOLUTION --

Anyway, I have found the culprit of my problem.

Turns out that both 3 groups had a mask layer which apparently was “damaged”, and when removed everything went back to normal. I'm not sure whether it was just a problem of defective layer, interaction of that layer with another layers, or maybe there were more defective layers which caused the whole issue.

One way or another the issue was caused by data damage revolving around some layers, so removal of damaged data from the file has fixed the issue.  

[Monika Gause · Accepted solution]

EPS can keep both layers and transparency in e.g. Ai,

By @łukaszt19747315

That will only work when you save an EPS in Illustrator.

And you will also need to save it in a way, so that it contains a complete AI file. Illustrator then won't even touch the EPS part of the file. It will go straight to the AI files. This procedure will only work in Illiustrator. Not in any other application.