RGB and CMYK numbers mean nothing without context. The context in these cases are the specific devices and working spaces that these are based on.
For instance, your RGB numbers mean nothing without knowing which working color space. The numbers in sRGB will not be the same numbers in Adobe RGB - if they are to represent the same color. You need to know what version of RGB is being referenced.
The same applies for CMYK. The CMYK numbers that Pantone uses for their ink builds are based on THEIR press runs and have nothing to do with anything or anyone else. The numbers that the Adobe programs generate for a specific Pantone color are based on both the Pantone Libraries that are loaded into each program AND, the CMYK profile that is loaded in the Color Settings in each program. The Pantone Library provides the program with the L*a*b values for each Pantone color, while the profiles loaded into the Color Settings (both RGB and CMYK) provide the conversion numbers that each program gives you for a particular Pantone color.
If you have all your settings and profiles sync'd across your programs, you should get very close to the same results, but there can still be slight differences due to the way each program does color conversions. Different versions of Adobe programs often use different versions of the Pantone Libraries which often have different L*a*b values, which will further confuse your efforts.
The best way really is to spec L*a*b values as they are device independent, but too many people don't know anything about L*a*b and that will just confuse the hell out of them. It's probably most effective to spec your RGB colors as sRGB, which is the most common default RGB color space and the space that people that don't know what they're doing are most likely to be using. The CMYK numbers should probably be reference to the most common offset printing standards in the areas where your customers are likely to be printing. Something like US SWOP Coated v2 or FOGRA or GraCol for most parts of the U.S. or whatever is used in your region. Whatever you do, just make sure to let people know that your numbers were created in THAT particular color space.
Thank you for your help
I agree with sasquatch15. It's very important to document what color settings you used to establish the color percentages. I would include LAB values for those who can use them. What I do is use Pantone CMYK conversions from their printed guides. I also document that the values did come from Pantone under certain print parameters. Web color gets a little interesting in that HEX values and sRGB values are completely different, but have to be included in the branding guide.
I did a little reading last night about hex colors and found that *some* are keyed off of sRGB and others are just a set of pixel values with no reference. Not really very helpful, but for people who don't mind remaining in the dark, maybe a comfortable place to be.
Hex color is just a relic from before color management was invented, and basically irrelevant and obsolete today. But many people still cling to it in the mistaken assumption that they are "absolute" numbers with general significance. Of course they are not - same principle applies: without a color space assigned, they're just empty numbers.
Insofar as hex numbers should be given, they should be treated the same way as RGB. And given the historical context of hex, the only reasonable assumption is sRGB.
As for CMYK, you can also make reasonable assumptions. Simply by virtue of being the default in most Adobe apps, US Web Coated (SWOP) is a fair assumption in North and South America.
Outside the Americas, however, SWOP isn't used at all. I don't know about Asia, Africa and Oceania, but in Europe most (serious) printers are ISO certified and presses standardized to ISO 12647-2. So a similarly fair assumption here is ISO Coated v2 300% (ECI), which is the one you most commonly encounter. The problem with that is that ISO Coated is not included in the Adobe installers, and you have to download it from ECI. So there's a threshold there complicating things.
In Adobe apps, the "Europe Prepress" setting puts up Coated FOGRA39 instead. This is still in use many places, but my impression is that it's being phased out in favor of ISO Coated.
In any case and bottom line - color space must be specified to give the numbers any meaning.