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Revision as of 05:31, 5 January 2025 editLittleHow (talk | contribs)Autopatrolled, Extended confirmed users3,688 edits Bloch's law is a surprising omission from Misplaced Pages, particularly given its related Ricco's law has an article. Many encyclopedias have articles on it or otherwise discuss it. I hope to expand itTag: Visual edit  Latest revision as of 06:07, 5 January 2025 edit undoCitation bot (talk | contribs)Bots5,432,651 edits Alter: title, pmc. Removed URL that duplicated identifier. | Use this bot. Report bugs. | Suggested by Jay8g | Category:CS1 maint: PMC format | #UCB_Category 
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'''Bloch's law''' observes that, for brief presentations, the product of luminance (or contrast) and duration at the detection threshold is constant. The law is due to Adolphe-Moise Bloch, who first formulated it in 1885.<ref>{{Cite journal |last=Gorea |first=Andrei |date=2015-08-01 |title=A Refresher of the Original Bloch’s Law Paper (Bloch, July 1885) |url=https://journals.sagepub.com/doi/10.1177/2041669515593043 |journal=i-Perception |language=en |volume=6 |issue=4 |doi=10.1177/2041669515593043 |issn=2041-6695 |pmc=PMC4934648 |pmid=27433317}}</ref> '''Bloch's law''' observes that, for brief presentations, the product of luminance (or contrast) and duration at the detection threshold is constant.<ref>{{Cite journal |last=Hildreth |first=James D. |date=1973 |title=Bloch's law and a temporal integration model for simple reaction time to light |url=http://link.springer.com/10.3758/BF03211177 |journal=Perception & Psychophysics |language=en |volume=14 |issue=3 |pages=421–432 |doi=10.3758/BF03211177 |issn=0031-5117}}</ref> The law is due to Adolphe-Moise Bloch, who first formulated it in 1885.<ref>{{Cite journal |last=Gorea |first=Andrei |date=2015-08-01 |title=A Refresher of the Original Bloch's Law Paper (Bloch, July 1885) |journal=i-Perception |language=en |volume=6 |issue=4 |doi=10.1177/2041669515593043 |issn=2041-6695 |pmc=4934648 |pmid=27433317}}</ref>
== Derivation ==

Consider that a brief flash of intensity <math>I</math> is presented for a duration <math>t</math>. Bloch's law states that detection occurs if the total luminance energy <math>I \times t</math> exceeds some threshold value <math>K</math>. Formally,<math display="block">I \times t = K</math>Here, <math>K</math> is a constant that can vary with different viewing conditions, observer attributes, and adaptation levels. Early measurements used single, isolated light flashes of varying duration and intensity to determine the boundary at which a viewer first reports seeing the flash. When plotted against detection thresholds, these data typically exhibit a near-constant product of intensity and duration for short intervals.
== See also ==
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== References == == References ==
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Latest revision as of 06:07, 5 January 2025

Bloch's law observes that, for brief presentations, the product of luminance (or contrast) and duration at the detection threshold is constant. The law is due to Adolphe-Moise Bloch, who first formulated it in 1885.

Derivation

Consider that a brief flash of intensity I {\displaystyle I} is presented for a duration t {\displaystyle t} . Bloch's law states that detection occurs if the total luminance energy I × t {\displaystyle I\times t} exceeds some threshold value K {\displaystyle K} . Formally, I × t = K {\displaystyle I\times t=K} Here, K {\displaystyle K} is a constant that can vary with different viewing conditions, observer attributes, and adaptation levels. Early measurements used single, isolated light flashes of varying duration and intensity to determine the boundary at which a viewer first reports seeing the flash. When plotted against detection thresholds, these data typically exhibit a near-constant product of intensity and duration for short intervals.

See also

References

  1. Hildreth, James D. (1973). "Bloch's law and a temporal integration model for simple reaction time to light". Perception & Psychophysics. 14 (3): 421–432. doi:10.3758/BF03211177. ISSN 0031-5117.
  2. Gorea, Andrei (2015-08-01). "A Refresher of the Original Bloch's Law Paper (Bloch, July 1885)". i-Perception. 6 (4). doi:10.1177/2041669515593043. ISSN 2041-6695. PMC 4934648. PMID 27433317.
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