I read this article today. I understood a few things, but few remained unanswered.
The article mentioned 18 basic colors. The things little confused me after that line. I assumed Pantone have only 18 spot colors currently.
So 18 basic colors are spot colors.
Okay, that’s about spot colors.
Now, in process colors, I understand so far that colors produced while printing by using C, M, Y and K inks are called process colors.
Also, the article mentioned that mixing of colors produce spot colors (if I understand correctly). So, when CMYK is also a mixing of colors and results in new colors, I wonder why the colors aren’t called spot colors.
Given all that, it may seem a lot of doubts, but the ultimate aim is to know the true meaning of spot colors and why CMYK mix is not same as spot color mix.
CMYK is not mixed. A printing process generally do not mix colors. It is kind of the holy grail of printing processes but it does not really exist as of yet.
What happens instead is that printing processes layer transparent inks on top of each other. Each ink only being able to produce either full ink color or no ink color. The indeterminate colors are achieved by alternating these cells of of ink or no ink on top of each other. Result is what looks like some value between the colors and white but is no where as rich as a mixed ink. We call a super cell of printer dots that produces a apparent color we call a print raster.
Spot colors on the other hand are mixed. So if you want lime green no problem lets mix lime green. You can again not print different mixtures, just rasterize different spots or process colors together but if all you want is lime green then you get it exactly as it is.
To understand the biggest difference between the two you would have to work with retail packaging. See in retail you have packages form different batches, possibly form different factories side by side. Now if there is a small but discernible color variation between these batches people would act as if the other batch is somehow tainted, they would gravitate towards the other batch, this leads to a lot of lost sales.
Now process color is more fragile when it comes to reproduction than spot colors. Mainly because reflected surfaces react with ambient light. The inks have some color spectra, humans of course do not see spectra. However when the surrounding light around reacts with the different inks something special can happen. They can under some lights seem the same and different when seen in other light condition. So while CMYK can reproduce same color under same light a spot color can reproduce the same physics as the other if substrate is same. Also if you are willing to mix custom proportions you can possibly get same color on other substrates.
You also get a cleaner color, and a wider gamut if you are willing to mix colors. You also get more even surfaces of same color and possibly gradients too. Also it is possible to dye plastics or fabrics with some spot systems so then you can order material in your exacting color, none of which you can easily do with process colors.