[cups] Mac OSX with CUPS 1.7.2 Printing fuzzy on Zebra GK420d

[Matthew Warren]

Machine:  Macbook Air 
OS: OSX 10.9.3
CUPS: 1.7.2
Driver: ZPL
Printer: Brand new Zebra GK420d



We are trying to print PDF shipping labels, these labels have high quality JPG images in them as well as text and a barcode. Here is the label https://www.dropbox.com/s/2bygmavx0tw17s2/label%20%2823%29.pdf

Problem: The quality is very fuzzy/distorted. The JPG images are the worst effected but even the barcode and text are not good. See photo here https://www.dropbox.com/s/in3g64f8g69sk2d/IMAG0062.jpg

Here is the error log from CUPS https://www.dropbox.com/s/88ipbc4bmtjsqho/error_log

Printer works fine on Windows machine. 

We have replicated this problem on multiple Mac machines (our customers) with the same setup as above.

We have printed hundreds of test trying various different solutions and we have only had any improvements when we load the PDF into Gimp and convert it to 1 bit colour (black/white) with a DPI of 203 save it in XCF format, its better but not perfect.  If we then save that into PDF format again, it makes it worse again.

We have tried converting to other formats like SVG/EPS without luck.

I can live with the text quality but the images and barcode are not good enough for the courier.  Problem seems linked to CUPS/Zebra when it converts the PDF to its 1 bit colour and does not do a great job, but I am no expert.

Desperate for some help/advice and I would be extremely grateful for any!