How can I find the closest Pantone colour when I have CMYK/RGB/HTML/L*a*b* values?

Pantone does not provide a defined cross-reference between colour data and solid Pantone colours, however, you can use Adobe Photoshop to enter the values and cross-reference to Pantone Libraries. Photoshop will default to the closest mathematical colour. The steps to do this are as follows:

1. From the main toolbar, click the foreground/background colour square to launch the Adobe Colour Picker
2. Type the desired values into the text boxes provided. Note the change in colour on the picker window.
3. Click the Colour Libraries button
4. Select your desired Pantone library from the drop list
5. Photoshop will display a range of seven colours, with one colour outlined with a black border. This is the default colour which is closest to the values entered
6. It is important to note that the above results are mathematical, and are also dependent upon the colour settings used in Photoshop. Results should always be compared to a current Pantone guide or book to ensure accurate colour.