«أَوْ يَكُونَ بَيْنَ تَصَوُّرَيْهِمَا تَضَادٌّ»
Or the two conceptions may stand in opposition.
Black and white can function as contrasting positive qualities when considered in an appropriate subject and respect. Describing different things by those colours achieves effective coordination when comparison is intended.
In logic, contrariety concerns positive opposed qualities that cannot coexist under the relevant conditions. This is different from strict contradiction or mere dissimilarity.