The New Color Scheme

The scheme was developed for digital use. Nonetheless I provide RGB and CMYK color codes (see below). This scheme was developed based on a requirements analysis, designed iteratively and tested in four user studies. Please bear in mind that colors are represented differently on diverse screens and devices.

The aim of this specific color choice was twofold: first, to represent a hierarchy of colors in line with the ordered dB-values, and second to highlight harmful values (exploratory notes below).

The scheme is recommended for the areal presentation of noise immissions in noise maps and can be used for all time periods. In case of line-like presentation, higher color contrasts have to be considered.

Fig. 2: The new scheme (version 5.b) with eleven classes was originally developed for ten classes. Another green-shade was added after a discussion with the committee for the revision of DIN 45682, to which this scheme was presented. The figure in the center shows that each one of the three color hues represents one distinct level of noise nuisance. The figure on the far right illustrates that areas with higher noise pollution are salient due to the darker and more saturated colors (color codes below). To facilitate distinguishability we recommend to represent only 7 ±2 classes! (Data source: anonymized data set „Silent City“ by Lärmkontor GmbH)

 

Exploratory notes on the color choice and design

• While saturation increases, lightness decreases for higher values. This design was chosen to highlight harmful (high) values.
• Additionally, the increase of saturation supports the representation of the noise pressure level’s logarithmic scale. This scale has the effect that higher values contribute more to the energetic mean value.
  
• Due to the decrease of lightness, colors can be ordered according the rising dB-values – the logic of the represented dB-values is thus mirrored in this scheme.
• The three color hues that are used – blue-green, orange, and purple – symbolize three levels of noise exposure and support recognition (Fig. 2, center). I chose a stronger color contrast for the classes 60 to 65 and 65 to 70 dB to indicate a high health risk (cf. WHO).
• The scheme is suitable for users with color vision deficiencies because pure green and red are not used in combination (Fig. 3).
• Nevertheless colors are intuitive, similar to a „traffic light scheme“: The cool blue-green colors are associated with lower values in comparison to the saturated and warm orange and purple colors.

Fig. 3: Version 4 of the original color scheme with ten classes (first from left) and simulated as users with color vision deficiencies might see it: deuteranopia – green blindness (second from left), protanopia – red blindness (third from left), and tritanopia – blue blindness (fourth from left). Conversion with the software Eye.syde.

 

Color Codes Scheme vs5.b
	Color	R	G	B	C	M	Y	K	Hex
>30-35	dark blue-green	130	166	173	53	23	28	4	#82A6AD
>35-40	Blue-green	160	186	191	42	18	21	2	#A0BABF
>40-45	light blue-green	184	214	209	33	6	19	0	#B8D6D1
>45-50	light green	206	228	204	24	1	25	0	#CEE4CC
>50-55	yellowish green	226	242	191	16	0	33	0	#E2F2BF
>55-60	light orange	243	198	131	5	26	54	0	#F3C683
>60-65	orange	232	126	77	3	61	71	0	#E87E4D
>65-70	dark orange	205	70	62	15	84	74	3	#CD463E
>70-75	magenta	161	26	77	32	98	47	14	#A11A4D
>75-80	purple	117	8	92	58	100	26	17	#75085C
>80	dark purple	67	10	74	79	100	37	39	#430A4A

The composition of the eleven-class scheme for the presentation of noise immission, e.g. the combined use of colors that are similar to the presented colors according to visual assessment or due to their color codes, by Beate Tomio is licensed under a Creative Commons Attribution – NonCommercial – NoDerivatives 4.0 International License.

If you wish to use the scheme and have questions concerning the license, please feel free to contact me: beate(dot)tomio(at)coloringnoise(dot)com.