PDF export on AI looking different to when opened elsewhere?

[defaulti1lkk08jtlf6]

File is in CMYK, the red and blue fade is Pantone Solid Coated. Looks completely fine when viewing on Illustrator and the Adobe PDF viewer, but creates a really bad brown line when opened in a browser PDF viewer. Any way to fix this?

[Ton Frederiks]

Did you use Overprint? That may not be supported by other (non Adobe) viewers.

If so, try if Darken Opacity Blending Mode instead of Overprint works better.

[defaulti1lkk08jtlf6]

Went to: opacity > darken. Is this what you mean?

[Ton Frederiks]

I believe it is just a regular blend between 2 spots.

In that case, not even Illustrator will be able to accurately preview the blending of the inks and other viewers (unless designed for prepress) will certainly not.

[defaulti1lkk08jtlf6]

This won't be printed out or anything, itll just be viewed online.

[Ton Frederiks]

Then it is probably better to convert the spots to rgb colors and convert the document to rgb, since monitors use rgb.