Need Guidance for Color Profile Settings in Illustrator

Question

What is the best color profile to start with in Illustrator when designing a Logo that will be used for web and for print? Do you need to work on them in two different files, one with CMYK profile and one with RGB? Currently I need to send my client's logo to be printed, but I need to make sure that my color profiles are set properly, and it seems like the CMYK and RGB values jump around on me, without color profile settings changing. For example, I start with a color I like, create the swatch, and jot down the RGB, CMYK and Web# values. Then I click on the swatch again and open it up and the values are different. Plus, the color I am looking at in the Color Picker window appears different when its filling my logo elements. It is driving me crazy!! Does anyone have any advice for me??

My current Document Color Mode is CMYK

My current color settings are as follows:

ADVANCED MODE: RGB: ColorSync RGB - Generic RGB Profile CMYK: ColorSync CMYK - Generic CMYK Profile

COLOR MANAGEMENT POLICIES RGB: OFF CMYK: OFF

Answer 1

Start with your target medium

I typically start where I know the most prominent/critical use will be. For a lot of clients, that's the web. For some, it's going to be outdoor, vehicle graphics, and uniforms. It's all over the place from one job to the next. You want to be sure you optimize the palette for the most important application.

Print

For print, pick the profile that most appropriately matches your application, eg SWOP or Sheetfed. Make sure your document color mode is CMYK and you set-up your swatches in or at least double-check by CMYK values. The most accurate way to work is with Pantone numbers (spot or process depending on your application). Color changes on press depending on the printer, paper, even environmental conditions. The printer can only understand your desired effect if you provide them with a standard reference. Even then, variation is hard to avoid.

Screen

When you need to transition this over for web use, create a copy of the doc and change your document color mode to RGB and your profile to sRGB. Now you'll want to go through and check your color values again to make sure you're getting what you want. The conversion from CMYK can not be perfect. It is a rare palette that does not require modification. The best way to check the RGB version* is to export a PNG 24 and view it in as many different browsers / monitors / systems as possible.

UPDATE:
*Here's how I test my web palettes these days. It's a simple HTML file that spits out color palettes. Look for the block below in the body of the page. Just drop in an array of color values in any web-friendly format then open the html file in your browser to test your color palette.

writePalette(
        'swatches01',
        ['red','#b00','#b00b00','#900','#400','break',
         '#bad','#bada55', 'break',
         '#decaff', '#c0ffee','#f09','teal']
      );