MANUAL FLATTENING SIMPLIFIED
Further clarifying what Mr. Jeff Harrison wants to say in his blog
Manual Flattening is the best solution to avoid any possible headaches in publishing to PDF or to RIP. Let's see how to manually flatten parts of a design.
NOTE: Before flattening, back-up your original unflattened .cdr file for future editing.
WHAT OBJECTS TO FLATTEN:
SIMPLE TECHNIQUE FOR FLATTENING
in any case, ensure that the stacking order of all elements is correct, meaning that after moving elements everything is visually layered the same way as it was in original design.
To convert certain elements to a single bitmap, select them, and go to Bitmaps > Convert to Bitmaps.
When converting these kinds of items to a bitmap, "resolution" is very important. If you are dealing with small items, like for example a business card, you need to convert it to bitmap at much higher resolution than you do a large dimension sign or poster. Some guidelines from Jeff:
For typical output on a CMYK device such as a printing press or digital color device such as a Xerox or Canon, choose the CMYK color model and have Apply ICC profile checked.
Have Anti-aliasing checked.
Don't check Transparent background.
NOTE: If you have more Vectors than Flattening Contents you can do the above mentioned process in reverse order; for example instead of creating layer above, you can create new layer and send it deep beneath the stacking order and start moving your Contents to Flatten down by pressing Ctrl+End
Flattened Contents (a single bitmap):