Semi-transparent layers enhance the simultaneous lightness contrast

Hdl Handle:
http://hdl.handle.net/10149/97433
Title:
Semi-transparent layers enhance the simultaneous lightness contrast
Authors:
Soranzo, A. (Alessandro); Fantoni, C. (Carlo)
Affiliation:
University of Triest
Citation:
Soranzo, A. and Fantoni, C. (2005) 'Semi-transparent layers enhance the simultaneous lightness contrast', Journal of Vision, 5 (8), p.564a.
Publisher:
Association for Research in Vision and Ophthalmology (ARVO)
Journal:
Journal of Vision
Issue Date:
Sep-2005
URI:
http://hdl.handle.net/10149/97433
DOI:
10.1167/5.8.564
Abstract:
Helmholtz (1866) reported that the redness of a gray target on a red background was enhanced by covering it with a Semi Transparent Layer (S-TL). We observed a similar effect in the achromatic domain: when a S-TL is superposed on the classic simultaneous lightness contrast display in order to cover both the targets, the lightness difference between the targets enhances compared to the condition without the S-TL. We explored this phenomenon in a CRT experiment using a simultaneous lightness contrast display with a mid gray (corresponding to 6 Munsell units) targets and S-TLs (transmittance = 50%) with different sizes and simulated reflectances. The relative size of the S-TL was varied amongst 5 levels: 1.3, 1, 0.74, 0.5 and 0.3 times the area of the black and white backgrounds. Two levels of the simulated reflectance of the S-TL were used: corresponding to 4 and 8 Munsell units. Observers were asked to select, from a Munsell scale, two patches: one matching the lightness of the target standing on the white background and the other matching the lightness of the target standing on the black background. Results showed that the lightness difference between the targets was enhanced, with respect to the condition without the S-TL, when the relative size of the S-TL was equal to 0.74, 0.5 and 0.3, while the lightness difference was reduced when the relative size was 1.3 and 1. Furthermore, the enhancement of the lightness difference increased as the simulated reflectance of the S-TL decreased. According to Soranzo and Agostini (in press) we suggest that these results could be explained by the relation among the luminance ratios between the Contextual edge (the edge in the surrounding area) and the Mediating edge (the edge in the enclosed area).
Type:
Article; Meetings and Proceedings
Language:
en
Keywords:
Helmholtz; semi transparent layer; lightness; Munsell scale
ISSN:
1534-7362
Rights:
If journal is published under a CC licence, copy of article can be stored in a repository. If no CC licence visible, link to article on journal website or request permission to archive a copy to the repository. For full details see https://www.oaklist.qut.edu.au/ [Accessed 27/04/2010]
Citation Count:
0 [Web of Science and Scopus, 27/04/2010]

Full metadata record

DC FieldValue Language
dc.contributor.authorSoranzo, A. (Alessandro)en
dc.contributor.authorFantoni, C. (Carlo)en
dc.date.accessioned2010-04-27T08:15:02Z-
dc.date.available2010-04-27T08:15:02Z-
dc.date.issued2005-09-
dc.identifier.citationJournal of Vision; 5 (8): 564aen
dc.identifier.issn1534-7362-
dc.identifier.doi10.1167/5.8.564-
dc.identifier.urihttp://hdl.handle.net/10149/97433-
dc.description.abstractHelmholtz (1866) reported that the redness of a gray target on a red background was enhanced by covering it with a Semi Transparent Layer (S-TL). We observed a similar effect in the achromatic domain: when a S-TL is superposed on the classic simultaneous lightness contrast display in order to cover both the targets, the lightness difference between the targets enhances compared to the condition without the S-TL. We explored this phenomenon in a CRT experiment using a simultaneous lightness contrast display with a mid gray (corresponding to 6 Munsell units) targets and S-TLs (transmittance = 50%) with different sizes and simulated reflectances. The relative size of the S-TL was varied amongst 5 levels: 1.3, 1, 0.74, 0.5 and 0.3 times the area of the black and white backgrounds. Two levels of the simulated reflectance of the S-TL were used: corresponding to 4 and 8 Munsell units. Observers were asked to select, from a Munsell scale, two patches: one matching the lightness of the target standing on the white background and the other matching the lightness of the target standing on the black background. Results showed that the lightness difference between the targets was enhanced, with respect to the condition without the S-TL, when the relative size of the S-TL was equal to 0.74, 0.5 and 0.3, while the lightness difference was reduced when the relative size was 1.3 and 1. Furthermore, the enhancement of the lightness difference increased as the simulated reflectance of the S-TL decreased. According to Soranzo and Agostini (in press) we suggest that these results could be explained by the relation among the luminance ratios between the Contextual edge (the edge in the surrounding area) and the Mediating edge (the edge in the enclosed area).en
dc.language.isoenen
dc.publisherAssociation for Research in Vision and Ophthalmology (ARVO)en
dc.rightsIf journal is published under a CC licence, copy of article can be stored in a repository. If no CC licence visible, link to article on journal website or request permission to archive a copy to the repository. For full details see https://www.oaklist.qut.edu.au/ [Accessed 27/04/2010]en
dc.subjectHelmholtzen
dc.subjectsemi transparent layeren
dc.subjectlightnessen
dc.subjectMunsell scaleen
dc.titleSemi-transparent layers enhance the simultaneous lightness contrasten
dc.typeArticleen
dc.typeMeetings and Proceedingsen
dc.contributor.departmentUniversity of Triesten
dc.identifier.journalJournal of Visionen
ref.citationcount0 [Web of Science and Scopus, 27/04/2010]en
or.citation.harvardSoranzo, A. and Fantoni, C. (2005) 'Semi-transparent layers enhance the simultaneous lightness contrast', Journal of Vision, 5 (8), p.564a.-
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