Different exports/preview's for same page

Hi @sylke5EF0 , if you are having problems with composite printers and lower end PDF viewers handling transparency blending mode effects correctly, try flattening the PDF on export. Composite printers typically have RGB drivers, and not all viewers are going to correctly color manage CMYK, so try this Output tab setup—if the PDF is exclusively for screen viewing set the Destination space to sRGB:

The PDF view in Safari:

Exclusion looks at the colors beneath and INVERTS the values, on a channel by channel basis, with white having the most effect and black having no effect, and which blend mode RGB/CMYK mode you're using makes a huge difference: most effects work better in RGB.

For eg. If you are working in CMYK mode and your background is 100% Black (i.e. 0c0m0y100k), when you overlay a white circle with Exclusion, the resulting color would be 100C100m100y0k.

If you reduced the opacity of your white circle to 50%, the resulting colour would invert exactly half... Cyan, magenta, and yellow would go from 0 to 50, and the black would invert from 100 to 50, hence the resulting colour would be 50c50m50y50k.

Regardless: Your PDF is not reflecting your appearance because you are not using Acrobat. Preview and most browsers do a very lousy job of honouring blend modes; they weren't designed for that.

As far as the final print, if you are printing to an RGB non-Postscript printer, all your colours are getting converted to RGB and then managed by the printer so your blacks may end up looking all the same.

With transparency effects it is very important to choose the correct document blend mode. Edit > Transparency Fill Space > Document RGB or CMYK.

Do you create your PFD via Export or Print? Export is strongly recommended.

Or do you print directly from InDesign? This is not so good,  better is to export a PDF first and print from Acrobat.

Maybe not all your fault, but from the images you posted, it isn't easy to understand what you have vs. what you want. 

My goal is to get the black and white overlay

You mean like this?

it's really difficult to guess what the printed outcome will be. 

Are you printing the PDF? From Acrobat? Or are you printing directly from InDesign?

I use the default print export settings. 

Not sure what you mean by that. Can you clarify?