The range is a function that can narrow the sample list to one or more color spaces. In an ideal scenario, custom ICC profiles should be used. Before making a final decision, it is essential to understand how the spot color will be reproduced in final applications. In printing technology, there are two basic scenarios: one involves ordering custom ink, and another is based on mixing primary colors. Both have pros and cons, but sometimes there is no choice - custom inks are unavailable for some printing technologies ( digital, ink-jet, LFP). Even if it can be used (offset litho, flexo, rotogravure, silkscreen), the key might be the price. 

Most color printing production uses four Primary colors: cyan, Magenta, Yellow, and Black. This method is used for most pictures and photographs.
For economic reasons, this is the most common solution adopted by all printing technologies on the market. Custom spot colors require additional printing units, which generates additional costs. Process CMYK printing uses screening technologies that allow the percentage of each channel to be set. Inks have to be transparent to enable interaction between four layers of inks. Primaries overprinted produce Secondary colors. Prminaries and secondaries plot color gamut, precisely described by ICC Profile. This profile is created where hundreds of C, M, Y, and k combinations are printed on a selected substrate with selected inks and then measured by a spectrophotometer. The result is a numerical description of printing conditions. A more extensive gamut means more colors can be printed with acceptable precision (tolerance).  

Example of spot process build:

Suppose the spot color is in the gamut. In that case, it can be transformed to CMYK values:

The CMYK process built for 3R2.72 is C=0, M=49, Y=24. ChromaSpot calculates coordinates for selected ICC profiles and makes a prediction of potential error.

Process Color Spaces

Coated CMYK (69%)

The color space of typical process print production is based on the ISO 12647 specification, known in Europe as Fogra51 and in the US as a GRACoL. It is the most common color space whenever printing is on coated paper. This was initially developed for litho (offset) presses but adopted as a standard by most others. As this space uses only four primaries, it has visible limitations. It covers 69% of the ChromaSpot library.

Uncoated CMYK

Created similarly to Coated CMYK based on typical uncoated paper. Fogra 52

Newspaper (25%)

This is a pretty tiny gamut because the newspaper substrate is low-quality

Coated ECG / HiFi  (80%)

The standard CMYK process can be extended to more primaries. In this example, a standard ECG profile developed by Idealliance in the US is CMYKOVG, and it has additional Orange, Violet, and Green colors that fill the most critical gaps in colors not covered by typical CMYK.

Common RGB Color Spaces

Adobe RGB

Most professional photographers and designers use this standard color space.

sRGB

Standard color space based on sRGB.icc profile. Most internet applications use smaller space.

P3 Displays

The new standard for Displays offers a pretty wide color gamut.

Sample Printers

This section presents a couple of examples for demonstration only. Please note that custom ICC profiles are required for a specific scenario. 

Please remember that presented numbers are specific cases - others may reduce an enlarged gamut. Samples 

Epson Photo Paper

This printer/substrate combination can print almost 100% samples  Selected Epson uses 11 inks — the gamut is vast.

HP Indigo Target

The selected combination offers 77% of space coverage. 

Colorado UPH

A selected combination is given as 91%

Arizona Styrene

The substrate chosen can handle, in this case, 80%.