Equal, equivalent, match, the same…these are all words designers and printers should use carefully.
When you change a file from a Pantone specific color to a CMYK equivalent, there is the misperception that the CMYK equivalent will match the Pantone color. This is just not true, and, the confusion might be a result of the words we are using. There are some Pantone colors that convert well and look nearly the same as their CMYK counterparts, and then there are those that don’t convert well at all.
I’m not sure we should use the words equivalent or match when it comes to proofs or inks or anything that is subject to interpretation by machines or people. Equivalent describes something that is equal in force, amount or value. The term implies that they are interchangeable and that we can substitute one for the other. Equivalent Fractions have the same value, even though they may look different. These fractions are really the same: 1/2 ~ 2/4 ~ 4/8. This is an accurate example of equivalent.
When printers use words like match proofs and CMYK equivalents, what we mean is that we are showing you our best representation of what your digital files look like. The defining line is where art, science and expectations collide.