(of an organism) tending to move toward light.
- ‘At higher temperatures D. pseudoobscura, D. simulans, and D. melanogaster become more photopositive, while D. ananassae and D. willistoni become less photopositive.’
- ‘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%.’
(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.’
We take a look at several popular, though confusing, punctuation marks.