First of all, not to lose colors, make sure you made the new document in CMYK color mode from the beginning. If you didn't make that, even you sent the file in PDF or Ai, colors will convert to CMYK in the printer if you didn't in the export settings. -------------- So make sure you started the document in CMYK. If you didn't, change the color mode before exporting file and try to change the color values to fix it. _________ If you are working in CMYK from the beginning, aving file In PDF is better than JPEG. You can also use File>Package and send the open source with all links and fonts.
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