Bad borders brush

[Kohiko]

Hi all, I drew some lines with the brush tool and expand them. Now I see kind of white pixels around those lines?

 

The lines stay this way, even when zooming or saving als pdf. Can I fix this?

[Monika Gause]

Is this file in the document color mode CMYK? And that black is 100 K?

[Kohiko]

Yep and yep

[Monika Gause]

In that case it's an antialiasing issue with 100 K

It doesn't matter for offset printing.

How will you output the file?

[Kohiko]

I need to send it as a pdf to the client (in pdf the lines are the same). I'm afraid they will have problems with the lines like this. They will bring it to a print shop. 

[Monika Gause]

Exactly how will it be printed?

[Kohiko]

I'm not sure, the only specs the print shop delivered are 'it needs to be pdf' and they found my question about specs really strange... It's an intern print shop owned by the company the client works for. 

The white pixels are also visible when I save to jpg. 

[Monika Gause]

The white pixels are also visible when I save to jpg. 

By @Kohiko

Yes, this carries over to raster formats.

If it's an internal print shop, have them run a test print. Probably it's printed digitally anyway. You can also try and add some color ink to the black. Or give them RGB data. But all this would depend on cooperation with them.

[Kohiko]

Btw I notice that the brush lines are this way even before expand