Open your browser and navigate to the Optiman website linked in the Resources section. Click on "Services" in the left-hand column and select the colored "RGB to Pantone" icon. This brings up a paragraph in French and four type fields.
Take a look at your RGB color properties. Determine whether your properties designate a separate value for the red, green and blue colors or are presented in hexadecimal form, which will be a six-digit figure.
Enter the values in the appropriate fields on the website.
Select the color from the list that most closely matches your RGB swatch. The first column of the list represents the Pantone color's distance from your RGB values. The smaller the distance, the closer to your color the Pantone swatch is.