I'll start by saying that I do understand that my objections might be mostly theoretical, and that use of a Pantone book by designer and printer can often give a commercially acceptable result (but with many caveats, such as only when viewed under identical lighting conditions). I just question their decision to omit the most useful information about their named colors. Rant follows:
I think Pantone has done a very good job with their concise explanation of the benefits of using the current Bridge color values…
https://www.pantone.com/color-intelligence/articles/technical/pantone-color-bridge-what-has-changed
"The new Color Bridge Guides are now produced with improved CMYK values that were created without manually adjusting individual colors, in order to illustrate results you can expect to achieve from a typical commercial printer."
But sign makers don't output on "typical commercial printers", which I take to mean offset press on paper. We typically use digital inkjets on vinyl or ACM or coroplast and many other substrates.
"Conversion of Pantone Spot color into CMYK, RGB, or other color systems is dependent on the specific print conditions for a given application. Therefore, the values provided within the Color Bridge Guide are not absolute, but rather starting points."
and
"The appearance of colors in guides and books can change over time as a result of handling, fading, improper storage, and light exposure, among other factors. For these reasons, we do not consider the colors in our printed guides the official color standards, but rather representations of the master standard color data."
So... Pantone warns us that the CMYK values they provide are NOT a standard, and we shouldn't rely on them but only use them as a starting point for an offset press. I can accept that... UNTIL they also tell us that the the printed swatches in the Guides are NOT an
official color standard AND they fail to provide access to their
master standard color data (i.e., a measurement in CIE color space). I don't see how one can say Pantone is providing a "standard" at all - at least, not by the capabilities of today's color specifying and measurement technology. I see Pantone as being more like a common color shorthand.
If Pantone were to truly be a Standard they would publish the measurements of their
master colors in CIE L*a*b* (or other device-independent color specification). Heck, they even show a photo next to the above quotes of a person measuring the L*a*b* of a printed Pantone sheet - a sheet which they admit is NOT a color standard!!!
Of course, if
printers had access to the L*a*b* we would not need to buy annual swatch books. Printers could measure their output with their own colorimeter / spectrophotometer (heck, Pantone
owns x-rite!) and directly determine the accuracy of their match to the designer's stated color intent. Of course, to avoid disappointment we hope that the
designer IS using a current visual sample (commercial swatch book, our output device's printed color chart, etc.) when they specify a spot color.
Pantone knows their product is becoming less relevant. That's why they produce items like "this year's fashion color book" and other schemes in order to induce the graphic arts trades to keep buying new books each year.