27 Spot Colour Limit

Hi,

I'm on Illustrator CC 19.2.1, Mac OS 10.10.3

We're a sign maker and have a 6 colour large format output device - CMYK augmented with light versions. It produces good results in CMYK, and using those extra inks produces some surprisingly good results at some of the harder to match pantone spot colours. To get spot colours out of the printer, we have to put spot colour information in.

What we wanted was a colour chart showing a full range of spot colours and their CMYK equivalents on one sheet so we have a permanent lookup, using pantone solid coated (C), alongside pantone colour bridge coated (CP), the latter switched over  to CMYK.

Here's the problem, on output we can only produce a print PDF that holds 27 spot colours, the rest are switched over to CMYK. We had no error warning whilst making the file, no errors etc. First sign of a problem is final checking the output PDF files and finding most of the spots are now CMYK. Opening into Illustrator, all the spots are present and correct.

So, we have a good reason to want this full set of spots, we have a printer that will support them, but Illustrator / Acrobat doesn't appear to support.

Is anyone aware of a workaround, besides clipping down to prints of 27 colours?

Many thanks,

davey.