LRV Guru Light Reflectance Value App

How To Find the LRV, Light Reflectance Value for a Color

LRV Guru™ App from The Land of Color


LRV Guru App iOS

NOTE: You cannot take a picture of a color and ascertain LRV.

You must use a Color Muse hand-held colorimeter to MEASURE color.

Guru App How To Video – Less than 10 minutes




The LRV Guru app assists with calculating color contrast ratios.  It does the math for you.  Scan samples with a tool called the Color Muse (info below) or enter manufacturer LRV data. LRV is an acronym that stands for Light Reflectance Value.  LRV is a measurement that tells you how much light a color reflects and conversely how much it absorbs. LRV runs on a scale from 0% black to 100% white.

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! You must use a Color Muse hand-held colorimeter to measure color.


Color consultants, architects, graphic designers, sign makers, lighting and interior designers use LRV data in several stages of color design planning.  Homeowners should use LRV as a benchmark as they choose colors because LRV indicates how much two colors will contrast or blend as well as how light or dark a color could look and feel once applied to walls.


Careful planning for proper visual ergonomics is paramount in color design for the built environment. Human supportive color palettes are important because the average observer will see hue differences first, chroma differences second, and contrast, lightness differences last. Examples where this is applied are doorways, ramps, steps, signage, and work surfaces.


Meeting LRV specifications is critical to maintain the integrity of exterior architectural elements like doors and vinyl siding. In addition, guidelines for LRV contrast ratios exist in many industries and are intended to ensure good visual ergonomics for everyone especially the visually impaired.


There is a standard mathematical formula predicated on LRV data points that has been used for decades to calculate the color contrast ratio between two colors.  The LRV Guru app performs that calculation for you.  Enter known manufacturer LRV data points if you have them or use the Color Muse (info below) to scan swatches of colors.


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.

TOOLS – D65 Illuminant 2° Observer

LRV Guru™ is integrated with the Color Muse. A hand-held color sensor that integrates cutting-edge light technology to compute accurate spectral values, regardless of ambient light.

Accurate color captures for color professionals to quickly match paint, textiles, carpet, tile, accessories and more. The Color Muse device is the latest color scanning technology that allows you to scan smooth or textured surfaces. … Scan colors and instantly find hue family, LRV, value, and chroma!.


• 90%+ match on fan decks
• <1 dE avg. on 2000 colors
• <0.25 dE avg. inter-instrument agreement


•​4mm diameter area
• D65 Illuminant
• 2 degree standard observer

•​45/0 measuring optics
• White calibration cap


•​Tri-stimulus XYZ sensor
• Full Spoectrum white LEDs
• Patented and patent pending color algorithms


• LCh

• and more


•​iPhone 5 or newer
• iPad 3rd gen or newer
•Color Muse Only – Android 5.0 or newer

•must have Bluetooth 4.x


•​280 mAh lithium-polymer
• 3,000 scans
•6 months standby time

•SB charging


•​1.08 inch /27.5mm diameter
• 2.17 inch/ 55mm tall
•1 oz / 29g weight

•USB charging



•​Bluetooth 4.1

Stop guessing about color and start controlling it – buy Color Muse and LRV Guru now!

LRV Guru™ + Color Muse = Unmatched Color Power!

NOTE: You cannot take a picture of a color with your tablet, smartphone, or camera and ascertain LRV. A picture of a color is just a captured image, it is NOT A MEASUREMENT! You must use a Color Muse hand-held colorimeter to measure color.


IMPORTANT! Defer to LRV data provided by manufacturer if available.

Disclaimer: Color Strategies, LLC is an Amazon affiliate.


Spectral data captured with Color Muse and the values and/or ratios ascertained using LRV Guru app are reasonably informative guidelines. Use a certified color lab for requirements beyond reasonably informative guidelines.

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The Color Strategist Color Wheel by Lori Sawaya