Visual Colour Assessment

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Long before Colour Measurement Instruments like Spectrophotometers and Chroma Meters were invented and became main stream quality and colour tools, visual comparisons were carried out. Even today, some of our most expensive brands still rely on the human sense of colour perception to ensure “Agreement” with measurement by instruments.

Appearance 

The human eye, together with the processing power of the brain is able to take into account a number of variable and varying conditions to come to a judgement when comparing two colours. For instance, we have to take into account:

  • Changing light sources (Daylight, artificial light, combinations of both)
  • Moving objects and shows
  • Varying observation angles
  • Size of the Object

When we take in all the data with our eyes, the mind processes it and renders a sense of how the object appears to look like. As soon as the conditions change, the mind will alter the perception, sometimes to exclude the change, and other times to adapt to a fresh appearance. This is why when you are in a hurry driving to work, a light can look green, even when its red. (Watch this video to see this happen to YOU)

Appearance therefore takes colour and effect into consideration.

Effect

There are many things that effect colour perception, sometimes on purpose, for example glitter in automotive paints, mixed colour fibres woven into Denim, texture on a plastic surface to break up gloss and more. The human eye takes everything into account at once while an instrument only looks at the colour. So while EFFECT may influence COLOUR, the Instrument only sees the colour under the current “Conditions” or set of parameters.

Colour

We have covered what a Spectrophotometer “Sees” in a previous blog but basically a total perception of the object is process, and a numerical value returned by the Colour Space Algorithm. It is when we start comparing what we “See” to what the Instrument “Sees” we sometimes start to say that the result does not seem to correlate with the actual visual appearance. This may actually be TRUE, and the main reason that you may see a different outcome to that of the Instrument, is that the Human eye is not adhering to a set of conditions, but is constantly shifting its perception to match both the changing conditions, as well as deciding what is USEFUL to the observer. As this process has resulted in many arguments between colleagues, customers and suppliers and the like, the first step in colour communication is to compare under LIKE conditions. If instruments are not available, the next best thing is to have a FIXED set of conditions in a Viewing Cabinet, or Colour Assessment Cabinet. While you can still have some errors, many are removed as you can select a standard light source (C.I.E. Norm) and a standard viewing angle. You eliminate ambient disturbances, shadows and light changes, and view a standardised object at an agreed angle. You can obtain Just Normlicht colour assessment cabinets from us, see

 View a video on Colour Assessment Cabinets