I am using latest Illustrator, colour settings Generic CMYK. Artworks will be printed in CMYK.
I have been supplied with Pantone colours that will need to change to CMYK for print process.
When I convert in illustrator the CMYK breakdowns do not match the Colour bridge coated Pantone to CMYK swatch book.
How can I fix this?
I don't understand what you mean by "Generic CMYK" ("Untagged"?). I don't seem to have that option (and I can't really see a use for it either).
To me a set of CMYK values doesn't make much sense without knowing which color profile it is intended for.
Your print provider should be able to give you the color profile they use (I'm assuming you are printing on paper). Use that color profile and your preview and conversion will be as precise as possible.
Pantone's CMYK values have always puzzled me. I don't know exactly which color profile they are using, but on their site they state that the Color Bridge color books are "Printed to ISO Certification so colors can be consistently reproduced".
The CMYK values provided by Pantone are to be seen as a general guideline. When you are not sure to use the same color profile as they used you will never get the exact same numbers (and they might even tweak the numbers).
Look for the Color settings (Command+Shift+K) might solve your problem.
Your provided artwork and your computer might be using different RGB profiles.But few things you need to know.
RGB and CMYK values are merely an estimation of how the color would be displaye or printed. Depending on the Ink providers, different combination of C, M, Y, K produces visibly different colors.
Pantone colors are supposed to be used where spot colors are required to print (One specific color for a brand color e.g. Coca Cola red means a specific pantone color which is supposed to print the same.
A bit off-topic but even with pantone colors, if the quantity of ink becomes low, the color doesn't print the same.
With your question, I'm assuming that You are provided an artwork where some Logo and brand graphics are used with Pantone color. When you click and try to convert their swatch to CMYK, it doesn't appear the same on the screen and doesn't match on the color book either .
The smallest answer : (it won't). If you'd try to match it on screen, it might print very differently than it's pantone.
If you are going to make sure 100% of printing the brand colors with pantone, you'd have to go through separate print jobs for the same artwork, one with Pantone and other with CMYK plates. Based on your artwork, your printer might suggest which job should print first.
Depending on the nature of the print job, If it's some marketing campaign and you have a margin of being flexible, you can easily depend on the converted CMYK values, (though they're not looking the same on the monitor).
One more thing we often do is to consult the printer (Person who prints the offset printing), make the hit and trial for different CMYK values and use the ones which our printer suggests to use.
