Many times you are asked to find the CMYK equivalent of a particular Pantone color. If you don’t have a Pantone to Process conversion guide available, you can use Adobe Photoshop.
There are a lot of theories out there as to how you can get the most accurate CMYK values (some area quite complex, such as first converting to LAB color before converting to process colors, etc.). But if you’re a pro you already realize that no Pantone color is going to match 100% in process printing anyway and the Pantone Color Bridge guide is the best and most accurate conversion method.
The Pantone Color Bridge Guide is expensive, so these are the fastest ways that I’ve come across that give the best results.
In Photoshop, it’s as simple as clicking on the foreground color at the bottom of the Tools palette and looking at the CMYK values in the dialog box. Obviously, you can also get the RGB, LAB, HSB and Hex color values at the same time.
Click on the 'Color Libraries' button, select which Pantone Library you wish to convert to (I chose Pantone Solid Coated in the screenshot below). Photoshop will automatically jump to the closest Pantone color in the list (it's the one with a black border). The match may not be 100% perfect, but it’s usually very close.