Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
감광약은 사진 필름에서 빛에 반응하는 물질입니다.gamgwangyakeun sajin pilmeuneseo biche ban-eunghan muljilimnida.A sensitizer is a substance that reacts to light in photographic film.