Bitumen is used to make Japan black, a lacquer known especially for its use on iron and steel, and it is also used in paint and marker inks by some exterior paint supply companies to increase the weather resistance and permanence of the paint or ink, and to make the color darker.
bɪtˈuːmɛn ɪz jˈuːzd tə mˌeɪk dʒəpˈæn blˈæk, ɐ lˈækɚ nˈoʊn ɪspˈɛʃəli fɔːɹ ɪts jˈuːs ˌɔn ˈaɪɚn ænd stˈiːl, ænd ɪɾ ɪz ˈɔːlsoʊ jˈuːzd ɪn pˈeɪnt ænd mˈɑːɹkɚɹ ˈɪŋks baɪ sˌʌm ɛkstˈɪɹiɚ pˈeɪnt səplˈaɪ kˈʌmpəniz tʊ ɪŋkɹˈiːs ðə wˈɛðɚ ɹᵻsˈɪstəns ænd pˈɜːmənəns ʌvðə pˈeɪnt ɔːɹ ˈɪŋk, ænd tə mˌeɪk ðə kˈʌlɚ dˈɑːɹkɚ.