FLATTENING : Adobe illustrator

I've just started experimenting with Flattening, using Forum to glean as much as I can on the topic and now I have a question. After Flattening in Ill/EPS, I notice boxlike hairline outlines around Effects and Type, except for this, layers and Effects are in correct order. What's causing this? Should individual layers be Flattened first, Flatten only transparent areas.

Many thanks,
-Lennox

Adobe says in their Transparency for Output Guide white paper ( CS3 ) that these are artifacts that will not show up in high res output 300ppi; but can be seen on some monitors. As I understand it, when you flatten, the transparent effect areas of the file are rasterized, and the remaining vector areas are left alone. Adobe recommends you supply your print vendor a live transparency file including live layers and have them do the flattening. Some print vendors may be fine with that advice, but I'd supply them: 1.) live file ( .ai ); and 1.) flattened, high res file ( .eps ). If you flatten yourself, you should only have to do it once, not layer by layer. Adobe also says it ships Illustrator with flattener presets. Make sure your raster effects / document resolution settings match your flattener preset ( i.e., flattener setup is 300ppi, 5280 / 2540dpi min., dpi ( high res ), use the same in your raster effects and document output resolution.

With that said, the artifacts could still show up on some low res desktop printers that do not have a sophisticated RIP and some monitors, but will not show up in a high-end, high res output device.

Look into "A Designer's Guide to Transparency for Print Output"; pgs. 19 - 23 'Best Practices...'; with a concentration on page 21 - "Minimizing Artifacts"; via Adobe's web site white paper section.

Yes, this is only a preview effect, it doesn't appear in high resolution final plates or films.

Thanks John and Mario, this is very useful to me.

Another question:
I have two shapes, one a closed path filled with solid black, the other shape is a compound shape with outlined strokes, the shape is filled with solid black, when printed the filled path is Rich Black and the compound shape is washed-out? Is caused by how the compound shape is created?

Again, many thanks.

You may be using some funky blending mode in your Transparency dialog. Also, check your Preferences > Appearance of Black and select "Use Accurate Black" instead of "Use Rich Black".

Funky, that is the reason, experimenting you know. I found what happened: somehow I added a transparency to the compound shape, I searched high and low for the reason...learning curve, thanks for your input.