Cromocon

Making the world more visible

LRV & CONTRAST

“Good contrast helps VIPs see the world more clearly – so measure the LRV”

  • Light Reflectance Value (LRV) is the light reflected from a surface

  • A surface’s darkness to lightness is measured from 0 – 100%  LRV
  • LRV data is essential to all the design and construction industries
  • The LRV of materials is measured with a handheld colorimeter
  • CONTRAST is the difference between two adjacent LRVs
  • For example a Door in a wall, or Nosing on a stair tread
  • Measure the LRV of a door – 10% for a dark wood, then measure the wall, 35%
  • The CONTRAST difference….25?
  • 30 is a basic requirement so increase the LRV of the wall to 45%
  • Then the CONTRAST is good for VIPs at 35+
  • Building materials’ manufacturers should now supply the LRV values
  • Architects, surveyors, purchasing managers, specifiers, access consultants and designers all need LRV data

 

What is LRV?

“LRV is the measurement of reflected light back from a material surface as a percentage”

  • The % of lightness to darkness reflected from opaque surfaces
  • It is not a colour reference
  • LRV % ranges from 0% for most Dark Colours/Black, to 100% for White
  • However, measurements rarely achieve a 100% for white
  • Some white paints with fluorescent additives may reach 90% +
  • Most dark, textured surfaces like carpeting reflect no light at all
  • So a 0% maybe normal as all the light is absorbed
  • The difference between two adjacent LRV % is the CONTRAST

Why measure LRV?

“Take the guesswork out of accessibility – save time and money by supplying the LRV data”

  • A critical element of a building should be visible at a safe walking distance
  • People with low vision need to be able to see a hazard 3 metres away
  • Good CONTRAST aids 93% of registered Visually Impaired People (VIP)
  • Designers can check the App for safe navigation for people with low vision
  • Design and build projects all require LRV data on proposed materials
  • Without LRV data, companies loose contracts, waste money and time
  • Manufacturers of building materials provide the LRV % for projects
  • LRV % is needed to calculate the CONTRAST between adjacent materials
  • So all materials should have an LRV % reference
  • Many countries demand this information prior to approving specifications
  • Relevant for millions of materials in the building industry worldwide

What is CONTRAST?

“Using CONTRAST between two adjacent surface LRVs prevents accidents”

  • CONTRAST is the difference between 2 LRVs
  • It is a straight one minus the other not a %
  • A CONTRAST difference (CD)  of 30 is a basic ‘rule of thumb’
  • CONTRAST is essential information for professionals in design and build
  • Suppliers publish the LRV % in their technical specifications
  • A 70 CONTRAST is vital for visibility of signage
  • The sign border, background colour or text needs this to stand out
  • High positioned signs are less easy to spot and read
  • Check this with the CROMOCON APP
  • All 5 FACTORS affect visibility