LRV Guru

P L E A S E -- R E A D -- B E F O R E -- Y O U -- B U Y!!!
Use this app for LRV and LCh°. LRV is Light Reflectance Value and LCh° is Lightness, Chroma, and Hue Angle which means you can download The Color Strategist color wheel and determine what hue family a color belongs to.
How It Works:
LRV Guru™ app can be USED ALONE to calculate known LRV value differences.
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LRV and LCh° are displayed via the "Compare" option from the menu.
LRV Guru™ app MEASURES Light Reflectance Value (LRV) when integrated with Variable, Inc.'s Color Muse hand-held colorimeter.
The spectral data captured with the Color Muse and the values and/or ratios ascertained using the LRV Guru app are reasonably informative guidelines - "in the ballpark", as they say.

Beyond reasonably informative guidelines would require certified measurements from a color lab.
NOTE: You cannot take a picture of a color with your smartphone or camera and ascertain LRV. A picture of a color is just a captured image, it is NOT A MEASUREMENT! To MEASURE LRV using this app, you must use a Color Muse or NODE+Chroma hand-held colorimeter.
FEATURE: You can adjust the contrast ratio. LRV Guru's default contrast ratio is set at 70% because it is the most commonly applied guideline. A significant bonus feature of the app is that the contrast ratio can be adjusted by tapping "settings" and positioning the slide bar as desired.