Definition of photopositive in English:


Pronunciation /ˌfōdōˈpäzədiv/ /ˌfoʊdoʊˈpɑzədɪv/


  • 1Biology
    (of an organism) tending to move toward light.

    ‘The frequency of lethal and semilethal chromosomes in the photopositive population was 43%, and those for the photonegative and the unselected populations were 18% and 27%.’
    • ‘At higher temperatures D. pseudoobscura, D. simulans, and D. melanogaster become more photopositive, while D. ananassae and D. willistoni become less photopositive.’
  • 2Physics
    (of a substance) exhibiting an increase in electrical conductivity under illumination.

    ‘Most maskants are photopositive materials and are designed to operate at low pH and to be developed (or stripped) in high pH solvents.’
    • ‘When a photopositive material is used, the photosensitive material situated on the active sensor surface is exposed, while the remaining photosensitive material remains unexposed.’