adobe illustrator - AI Color Picker Panel and Pantone Color Finder shows different color values (CMYK, HEX and RGB) for a Pantone Colour

I am working on a brand identity and have finalised a stock colour Pantone 3415U (Solid Uncoated). I am having difficulty finding the matching colour values for the same in CMYK, RGB and HEX/HTML. I was using Adobe Illustrator and Pantone’s color finder (http://www.pantone.com/color-finder/3415-U) and both are throwing up different values.

Values for Pantone 3415U in Pantone Color Finder

RGB - 48, 129, 103 
HEX/HTML - 308167 
CMYK - 90, 5, 80, 14 

Values for Pantone 3415U in AI Color Picker Panel

RGB - 45, 127, 103 
HEX/HTML - 2D7F67 
CMYK - 81, 29, 67, 12

What among these are are the correct (the closest) values and also, is there a more reliable way to find the matching CMYK, RGB and HEX values for a Pantone Colour?

Answer

OK. Easy bit first. You don't need RGB and HEX versions, they are just different representations of the same numbers, but you can include both if you like for ease of use for people who don't know that. The other thing to remember is that you don't need to worry about which RGB colour is the best match for a Pantone if it's use is for web and digital. You can't control the screen brightness or temperature that the colour will be viewed in so there's no need to lose any sleep over it. Just pick a colour that looks right to you and the customer on a reasonably wide range of devices. This doesn't have to be any value that is produced by a colour picker, you can tweak it to your liking, but the above numbers will give you a good starting point.

The matching of a Pantone out of CMYK is a whole different can of worms and a full explanation would be way to broad for this format, but I'll give you a couple of pointers...

Firstly, you need to get a real printed sample of the Pantone from a print company that will be producing the bulk of the print for you and get this approved by the customer (or whoever) as the master standard, then forget about Pantone numbers and use this as your master brand colour. This can then be used to supply samples to other printers for them to match to whenever printing anything for that brand.

Secondly, (or in parallel to the above) don't tell the printer what CMYK split to use to match the colour out of CMYK, let them yell you. Most decent printers will have a repro department or an external repro agency who can produce calibrated proofs to predict one or more best matches before going to press and then run a sample on press to validate it. Again, this then becomes your master brand colour for process printing. The CMYK split won't necessarily be the same for ever process, printer or substrate, but all should be the closest achievable match back to the master brand colour.

Obviously, the above work all has an associated cost which may or may not be viable or desirable for any given product. Big brands spend tens of thousands of pounds on colour management, because it's worth it when you spend millions on packaging.

Smaller companies often have to stick to just telling a printer to match to a Pantone and/or use one of the above CMYK splits and hope it's a good match. Fortunately, the colour that you have picked isn't especially bright or clean so a good CMYK match should be pretty easy to get.