FAQ Logo


At what distance can colours still be distinguished?

It depends on chromatic contrast and viewing conditions, but experimental results show that generally an object that has a distinguishable shape at a certain distance, needs to be about two times bigger for distinguishing its colours at the same distance.

Which colours are invisible?

In the animal reign, colour vision is an attribute of the eye and depends on the species. Colours associated with wavelengths in a certain bandwidth spectrum can be seen by some animals but are invisible to others. Within the same species there can be colour vision deficiencies that make certain colours invisible. For example, humans have a deficiency called "colour blindness" that results in not seeing colours that an average human being can normally see.

Do colours affect eye sight?

Exposure to a limited number of colours, like wearing sunglasses with lenses of a certain colour, can produce long-term adaptation which results in less sensitivity of the eye to that colour. This is reversible. However, staring into the sun without protective lenses can produce blindness, but not as effect of the radiation in the visible colour spectrum.

How are colours named?

Colours have abstract names, such as red, or descriptive names, such as orange (which describes the colour of the fruit). There is a high degree of universality in the use of basic colour terms across cultures and languages but non-basic terms are used without the same generality and consistency as the basic terms. The Traditional Thai Colour Name Dictionary of Pichayada Katemake and Razvan I. Preda, published recently by Color Research and Application Journal is a good example of how colours are named. The book "Basic Color Terms: Their Universality and Evolution" by Brent Berlin and Paul Kay is a good start for understanding colour naming.

Black and white are colours?

Yes, they are. In every-day language they are not considered colours. One usually refers to a coloured picture as opposite of a black and white picture, or to a colour TV set as opposite of a black and white TV set. One would say that an object without colour is black or white, or is black and white. But technically speaking, black and white are colours.

Why is Facebook blue?

Mark Zuckerberg, the creator of Facebook, is red-green colourblind. This means that blue is the colour he can see the best. "Blue is the richest color for me. I can see all of blue" Zuckerberg told in an interview with New Yorker reporter Jose Antonio Vargas. This might be the reason why Facebook is blue.

The most frequent question related to the Traditional Thai Colour Dictionary is about the colour tolerances for the given CIELAB values of each identified colour.

We answered this question on our official facebook page but we are answering here as well. Publications about identification of colour names give usually their quantitative descriptions with tolerance in lightness and colour resulting from the methods they use for identification. Some publications describe methods to identify pigments and colors of painting with physical and/or chemical techniques while others describe choices made for interventions on painting within determined colour tolerances. Each study starts from available or accessible data and so does ours. But the accessible data for starting our study was of a different kind, due to “the extreme negligence showed in the preservation of this national heritage” as Klaus Wenck mentioned in ‘Mural Painting in Thailand’ in 1975 and as results from the recent publication (2010) ‘Thai Mural Painting’ by Gerhard Jaiser (second volume, chapter 3). Although colours in temples with traditional knowledge disappearing is common to more countries than Thailand, the problematic in Thai temples is particular to Thailand and Thai culture. This problematic was presented very well by Micaela Du Guerny in 1979 and we explained it briefly in the abstracts and introductions of the 4 articles we published. Our whole method relies on establishing acceptable colour tolerances for quantitatively describing each colour name, based on the majority opinion of artists who still know these colour names. We developed an elaborated methodology to average CIELAB colors of inhomogeneous paintings, to build representative colour groups for each colour name within specified colour tolerances, and an automated way to match the most representative colour established for each colour name with Munsell and NCS digital dictionaries. The final results are Munsell and NCS matches calculated by the Trichromatic Color Analyser system through our identification method, which were visually confirmed by a majority of artists specialized in traditional Thai Colours. The final Munsell or NCS patch resulted from our identification process that was visually confirmed as best match for a colour name was immediately measured with a spectrophotometer and its CIELAB values recorded for that colour name in the Traditional Thai Colour Name Dictionary. This measurement is absolutely necessary, because our Munsell and NCS patches might have different colours compared to other sets of Munsel and NCS patches due to colour degradation. More than that, the colour of our own Munsell and NCS patches may shift in time. Therefore, just indicating the colour codes of the patches, without an immediate measurement of their CIELAB values, is not sufficient. As result of our applied methodology, created for the particular case of Thai traditional colours, each identified colour is represented through unique CIELAB coordinates. However, each of these CIELAB coordinates represent best matches within colour tolerances, as specified in the articles. You will have to read carefully our articles in order to understand exactly the colour tolerances applied in our calculation method. Depending on the usage of the CIELAB values from the Traditional Thai Colour Dictionary, situations impose different approaches to consider colour limits for showing the colour names visually. If the aim is to show them on a screen, then the CIELAB can be electronically converted to RGB. The RGB values should be used for composing the colour only after a screen calibration. Colour differences will result in this case from the conversion process and from calibration. If the aim is to apply a paint colour on a substrate, then the CIELAB values from the Dictionary can be introduced in a colour matching software (like the one made by X-Rite), and the software will indicate a mix of dyes that have to be applied for obtaining the desired CIELAB values. The software must have a database suitable for the considered substrate (if it has not, one must be created). The resulted dye mixtures are based on imposed colour tolerances, which can be set tight only if the database is large enough to offer a wide selection pool of dyes for mixing. Generally, establishing an acceptable colour tolerance depends on the colour itself. Considering exclusively the 2000 formula for determining colour tolerances, a difference of 1 unit is always imperceptible but not practical. Usually, differences of 2, 3, 4 or even 5 units, in case of less sensitive colours, can be acceptable colour differences (especially for an untrained eye). The decision must be taken individually based on: each colour's characteristics, available database and chosen substrate. We strongly recommend you to read our articles (accessible at www.thaicolour.com/downloads.html) and afferent literature regarding colours, dyes, substrates and acceptable colour tolerances in different situations.

Copyright (c)2013-2015 Thai Colour Science Research Unit, Faculty of Science, Chulalongkorn University.
No website builders or code generators were used for creating this website. Authored by R. I. Preda and P. Katemake. Published and maintained with personal funds