1

I had a little research, but I can't explain this little anomaly I have here.

When I save a PDF with Document Raster Effect turned to 72 dpi it will have the same size as the file when I switch these settings to 700 dpi.

both 62kb.

The printer shop wants the pdf to be 300 dpi and saved as pdf. But where is the value when it's the same file size?

Can someone explain?

3

For an Illustrator file, that seems perfectly normal.

Illustrator mainly draws resolution-independent vectors: images built up with curves and anchor points rather than pixels. Since .pdf is capable of containing vectors as well, Illustrator will store its vector art in a .pdf as actual vectors. Talking about resolution in a vector-only file is useless: it contains not a single pixel.

So, provided you haven't been using any of Illustrator's bitmap/pixel capabilities (shadows or blurs, for example) and haven't placed any bitmap images into the Illustrator file, the .pdf file size should be identical, independent of the export resolution you choose.

Then why would a printer ask for a high-resolution .pdf? Well, printers tend to receive bitmap-based files as well. Those do need to have a proper resoltion, for they contain pixels. I'd even guess that your vector-only job is an exception rather than the rule.

The Document Raster Effect setting you mention is only to determine the resolution of any raster effect you choose to use. If you don't, the setting is moot.

2

I suspect your raster items are placed raster images.

The Document Raster Effects Settings (DRES) do not alter placed images. They only alter the raster items created via the Effects menu.

Changing the DRES options will have no effect on raster images you've imported from other applications. Images from other applications are imported at their existing PPI and only reducing or enlarging those images will alter that initial PPI.

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