Table 7.

Chromatic modifications of tuff stones after brushing treatment. L*: black-white color; a*: red-green color; b*: yellow-blue color; ∆E: color change.

Samples	L*	a*	b*	∆E
NYT/REF1	60.98	4.08	21.06	4.69
NYT/LS_br	56.87	4.53	23.24
NYT/REF2	68.03	2.02	18.26	6.83
NYT/NE_br	62.57	2.33	22.30
CI/REF1	67.05	2.65	17.02	4.98
CI/LS_br	62.46	3.43	19.11
CI/REF2	68.66	4.03	17.96	4.62
CI/NE_br	64.85	4.42	20.54