I'm grappling with the application of ASTM E-308 to SRM measurements in beer. The project I'm working on necessitates a reliable conversion from SRM to RGB (or sRGB) through the Lab* route. It's clear that each site I visit for beer recipe creation has its own unique SRM to RGB conversion method, given the complexity of the task. To address this issue, I am considering developing an open-source JavaScript library to tackle this challenge.
My approach involves using an algorithm outlined here:
This algorithm is believed to be a simplified version of the E-308 algorithm. However, I'm facing difficulty when referencing the spreadsheet provided in the linked post (). Selecting a XYZ vector based on the observer angle specified in the spreadsheet (such as a 10-degree observer angle) raises questions. For instance, if I opt for a 10-degree observer angle, should the corresponding XYZ vector be (82.82, 3.48, 61.86)? Is this calculation correct?
Additoinally, choosing an illuminant spectrum adds another layer of complexity. If I choose illuminant C (presumed to have a color temperature of 6774K), how do I determine and incorporate the appropriate components into the spectrum? How are these components calculated in the first place?
While I have some understanding of color theory, what I truly aim for is a streamlined process where I can input certain criteria like observer angle, illuminant color temperature, as well as the SRM value, and obtain the corresponding Lab* value.