What is ISO/TR 17321‑5 about?  
There are many application areas such as medical imaging, cosmetics, e-commerce, sales catalogue, fine art reproduction, art archive, etc. where colorimetric image capture and colorimetric image reproduction are desired. When precise colorimetric reproduction is required for the subjects that include highly saturated colours, it is desirable that overall sensor spectral sensitivities are close to linear combinations of CIE 1931 colour matching functions. 
ISO/TR 17321‑5 describes sample methods to generate spectra for colour targets comprised of highly saturated colours for colour characteristic evaluation of colorimetric image capture capability of digital still cameras (DSCs).
Who is ISO/TR 17321‑5 for? 
 ISO/TR 17321‑5 on colour characterization of digital still cameras is useful for: 
- Digital camera manufacturers
- Digital Photographers
- Digital camera designers 
Why should you use ISO/TR 17321‑5?  
 The real DSCs have overall sensor spectral sensitivities that deviate from the linear
combination of CIE 1931 colour-matching functions, and yet reproduce reasonable colours for general low-saturated colour objects. This is because most of the spectral distribution of real-existing objects is well self-correlated in the wavelength direction. This is also true for the frequently used colour target such as X-rite colour checker classic.
Therefore, when precise colour reproduction is required for highly-saturated colour objects, it is important to use spectral distributions that are less self-correlated in the wavelength direction, for the evaluation of overall sensor spectral sensitivities.
For this purpose, ISO/TR 17321‑5 proposes two methods for generating highly-saturated colour targets. The first method is a statistical extension of existing objects spectra, and the second one is a selection from artificial (LED-based) spectra.
ISO/TR 17321‑5 describes how these highly saturated colour targets can be used for goodness evaluation of overall sensor spectral sensitivities. Applicability of several existing evaluation metrics (such as Voraʼs μ-factor and Sharmaʼs FOM) are compared, using highly saturated targets generated by the methods proposed in ISO/TR 17321‑5.
ISO/TR 17321‑5 gives details on colour gamut of boundary colour and gives more information on colour differences of patches of CDSW target
