Color & light sources

Light sources Color assessment cabinet
Color consistency: the problem
Vteke products and technologies provide solutions to a naturally occurring problem. Namely, that a color looks different when viewed in different light conditions.
The difference may be extreme and obvious. For example, a car that is bright red in daylight may appear brown under sodium street lighting. But in supply chains, even minor differences in perceived color can be problematic.
Color accuracy is a major concern for manufacturers asked to supply products in very precise shades. Color checking in natural daylight won’t work because there is no such thing as uniform daylight. It differs according to time of day, season, location, climate, weather and atmospheric conditions.
As a result, colors that look right when manufactured may look wrong when delivered. And if disputes then arise, how are they to be resolved?
(It’s worth noting that color perception varies from human to human, and we can each recognise several million colors. Unsurprisingly, it can be difficult to get even two people to agree that a particular shade is ‘right’ or ‘wrong’.)

The Vteke solutions
The Vteke solution is a range of products based on:
Standardised artificial light sources
Vteke provide lamps mimic daylight to international standard D65, or to other standards specified by major retailers, such as TL84,UV, CWF,TL83, U30,D50 etc.
If everyone in a supply chain uses the same agreed light source, variations in natural light become irrelevant. Color can be viewed and measured in exactly the same lighting conditions at every stage of design and product development.

Understanding color and light sources
In industry, color assessment plays a growing role in quality assurance. To get reliable results that everyone can agree on, three essential requirements are:
A high quality light source.
Standardised viewing conditions.
A means of capturing objective data.
Let’s look at each of these in more detail.

Light sources (D65,D50,TL84,UV, CWF,U30, TL83,D75 etc.)
Vteke provide lamps from Philips, Sylvani, GretagMacbeth, VeriVide etc, specifically for color viewing inpection, the most important 3 features to color matching lamps:
Color temperature (K)
This has nothing to do with heat. It describes the appearance of the light a lamp emits. The lower the color temperature, the ‘warmer’ (redder) the light; the higher the temperature, the ‘colder’ (bluer) the light.
Color rendering index (CRI)
An index from 0-100 measures how faithfully colors are rendered by a lamp compared to a reference light source. Low values indicate poor color rendering, while 100 is an exact match.
Spectral power distribution (SPD)
Different light sources emphasise different parts of the color spectrum, affecting how the eye sees color. SPD rating classifies each light source. Vteke provide the lamps is internationally recommended for color assessment, as it emits the whole color spectrum almost equally.

Standardised viewing conditions
Everyone in a supply chain needs to ensure that their viewing equipment and environment meets internationally agreed standards.
Best practice is to use Vteke Light booth CAC series (color assessment cabinets) These ensure an identical viewing environment throughout the supply chain.
Color assessment cabinets must have neutral and blemish-free matt grey interiors and a high quality, distortion-free lamp reflector.
The siting of the cabinet is also critical. All external sources of interference should be removed. For example, nearby windows should be fitted with grey blinds and nearby general lighting should be Vteke 200-300 lux Artificial Daylight.
It is good practice to offer color perception testing to personnel involved in making color decisions.
It is also advisable to consider at design stage the desired appearance of products at point of sale or in everyday use, as most products will ultimately be seen and judged in environments outside the supply chain.