Quantifying light harshness: method automation and influence of photographic light modifiers

Štampfl, Veronika (author), Ahtik, Jure (author)

Accurate assessment of light properties is essential and is measured with photometric and colorimetric standardized methods. However, the spatial characteristic of light-harshness-remains difficult to quantify. Building on the authors’ previous work, this study presented a fully automated method for determining light source harshness based on image analysis of cast shadows in a standardized environment. The improved method eliminated the need for manual shadow segmentation by introducing algorithmic noise removal and adaptive smoothing of shadow data. The method was applied to 180 test images comprising 30 combinations of photographic light-shaping attachments (e.g., softboxes, beauty dishes, and snoots) across two light sources (halogen and xenon) and three intensity levels. The results showed that the method was capable of detecting subtle differences in shadow properties and confirmed the influence of geometry, material, and orientation of the light modifiers on harshness. In addition, the results provided quantitative insight into the influence of photographic light modifiers on the original light.

• Language: English
• Keywords: light harshness, shadow analysis, image processing, lighting evaluation, photographic modifiers
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 17 str.
• Numbering: Vol. 12, iss. 4, art. 148
• PID: 20.500.12556/RUL-181714
• UDC: 655
• ISSN on article: 2313-433X
• DOI: 10.3390/jimaging12040148
• COBISS.SI-ID: 273760515
• Publication date in RUL: 14.04.2026

Record is a part of a journal

• Title: Journal of imaging
• Shortened title: J. imaging
• Publisher: MDPI AG
• ISSN: 2313-433X
• COBISS.SI-ID: 525653017

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: trdota svetlobe, analiza senc, obdelava slik, vrednotenje svetlobe, oblikovanje svetlobe

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0450-2024
• Name: Inovativna grafična tehnologija