Useful notes for a hair shade reference sheet

My natural roots are becoming visible, and I have started a small photo diary of the change. A photograph now contains two quite different shades, so describing my hair with one label seems unhelpful. I am looking for a consistent way to compare the sections, not a prediction of how the finished result will look. For context on describing hair shades, I saved a page about hair colour analysis and began separating observations about roots from observations about the older dye. A regular photograph against one background might help, particularly if I include the parting each time. Each entry would record the lighting and whether my hair was wet, dry, or freshly styled. I would like to review the record over several months, with dates and consistent descriptions that make small changes easier to follow. Would separate root and length notes make this easier to follow, or is there a simpler format?