ɐ pˈɜːfɛkt ɹᵻflˈɛktɪŋ dᵻfjˈuːsɚ pˌiːˌɑːɹdˈiː ɪz ɐ θiəɹˈɛɾɪkəl pˈɜːfɛktli wˈaɪt sˈɜːfɪs wɪð lˈæmbɚʃən ɹᵻflˈɛktəns ɪts bɹˈaɪtnəs ɐpˈɪɹz ðə sˈeɪm fɹʌm ˌɛni ˈæŋɡəl ʌv vjˈuː.
A perfect (reflecting) diffuser (PRD) is a theoretical perfectly white surface with Lambertian reflectance (its brightness appears the same from any angle of view).