Sounds too good to be true? You just need the right computing app.
Or just make a new test strip, which by design factors in all of the variables you mention. Only takes a moment. And doing so puts you in closer touch with the materials you are working with, instead of inserting additional layers of indirection and logically abstracting you further away from them.
"Hate is an adolescent term used to stop discussion with people you disagree with. You can do better than that."
—'blanksy', December 13, 2013