▁ 0 . 3 ▁mm ▁w avel ength ▁W b ▁ 0 . 3 ▁ ........ ▁ 1 ▁mm ▁w avel ength ▁W c ▁ 1 ........ .... ▁ 3 ▁mm ▁w avel ength ▁W d ▁ 3 ▁.... ..... ▁ 1 0 ▁mm ▁w avel ength ▁We ▁ 1 0 ▁.... ... ▁ 3 0 ▁mm ▁w avel ength ▁SW ▁ 0 . 3 ▁.. ... ▁ 1 . 2 ▁mm ▁w avel ength ▁L W ▁ 1 . 2 .... ... ▁ 1 2 ▁mm ▁w avel ength ▁Sim pl ified ▁Me asure ment ▁Di agram ▁ ▁Struct ures ▁smaller ▁than ▁ 0 . 1 ▁mm ▁also ▁influence ▁visual ▁per ception , ▁therefore ▁the ▁instruments ▁use ▁a ▁C CD ▁camera ▁to ▁measure ▁the ▁diff used ▁light ▁caused ▁by ▁these ▁fine ▁structures . ▁This ▁parameter ▁is ▁referred ▁to ▁as ▁" d ull ness ". ▁ ▁The ▁values ▁of ▁d ull ness ▁and ▁Wa ▁to ▁We ▁form ▁a ▁" structure ▁spectrum ". ▁This ▁allows ▁a ▁detailed ▁analysis ▁of ▁orange ▁pe el ▁and ▁its ▁influen cing ▁factors , ▁being ▁material ▁or ▁application ▁parameters . ▁Example ▁of ▁a ▁" structure ▁spectrum " ▁ ▁The ▁detailed ▁information ▁of ▁the ▁structure ▁spectrum ▁as ▁well ▁as ▁L W ▁and ▁SW ▁became ▁the ▁basis ▁to ▁correlate ▁to ▁specific ▁scales ▁and ▁to ▁the ▁DO I ▁as ▁described ▁in ▁A ST M ▁E 4 3 0 . ▁ ▁Ph ase ▁stepped ▁def lect ometer ▁ ▁Ph ase ▁stepped ▁def lect ometry ▁( PS D ) ▁is ▁a ▁white ▁light ▁optical ▁technique