VeriVide Daylight Model: F18 T8/D65
Size: 2 Feet
What is white?
A seemingly simple question can have many answers, depending on who you ask. And for many applications, the exact definition can have significant consequences.
In this article, we’ll go through the exact specification and how you can use this to make smart decisions about white lighting purchases.
Why? Just like with CRI in lamps, different shades or spectral compositions of white light can produce different appearances.
This is why a D65 light source is crucial for accurate color perception and evaluation.
Unlike correlated color temperature (CCT), for which the same CCT value can have different green/magenta hues, D65 unambiguously defines an absolute spectrum and color point. (More on this below).
Note that for graphic arts and printing industry applications, a similar but different standard called D50 is used.
D65 for Bias Lighting
D65 is a very common standard used for monitor and display calibration. In short, this means that when a monitor attempts to display a pure white point (e.g. RGB values of 255/255/255) the color emitted by the display matches exactly the D65 color point.
When performing color-critical tasks on a monitor or display, ambient lighting conditions can alter our perception of the colors on the screen. While these may be fun “optical illusions” for everyday people, this phenomenon can be extremely detrimental to producing or evaluating color-critical work on a computer screen.
In the graphic above, squares A and B are the exact same shade of grey! (Yes, it’s hard to believe, but it’s true.) Due to the color of the surrounding squares, our visual system perceives B to be “white” and A to be “black” despite them being the same shade.