In a previous study based on monitor simulations of artistic paintings, it was found that the average correlated color temperature (CCT) of daylight preferred by a large set of observers to illuminate paintings was around 5100 K. The goal of the present study was to test if this result holds in real viewing conditions, i.e., with real paintings and real light sources. The same 11 paintings were tested in real conditions illuminated by a spectrally tunable light source and with accurate monitor simulations. To ensure uniform illumination across the paintings, only a central part of the paintings was visible to the observers. It was found that the average CCT preferred for real and monitor viewing conditions were very similar, 5500 and 5700 K, respectively. The somewhat larger CCT obtained with monitor viewing in relation to the former study was only observed in some paintings and was attributed to the smaller viewing area. These results confirm that CCT for best appreciation of paintings is higher than normally used in museums, and the viewing conditions, real or simulated, have only a minor effect.

Best lighting for visual appreciation of artistic paintings—experiments with real paintings and real illumination

LEDs as a tool to enhance faded colours of museums artefacts

Light is needed to appreciate artwork, but visible radiation causes damage by photochemical action. Photons trigger photochemical action only when they are absorbed by the object. Damage to sensiti...

https://www.tandfonline.com/doi/pdf/10.1080/15502724.2018.1533852

Spectral Optimization to Minimize Light Absorbed by Artwork

Spectrally tunable light sources for general lighting have recently attracted much attention as versatile solutions that can be used in humancentric lighting implementations provided with excellent color rendering and increased user perception. However, temperature and age-dependent color shifts and flux variations in the light-emitting diode (LED) emission are nonresolved challenges that need to be overcome in order to be used in final applications. We demonstrate two strategies that can be used to efficiently and precisely generate arbitrary spectral power distributions (SPDs) using multichannel LED engines. First, we introduce different methods to match a given SPD and select an algorithm (simulated annealing) in virtue of its speed (in the milliseconds range) and accuracy (color shifts Δu  ′  v  ′    <  5  ×  10  −  4). Then, we propose a closed-loop feedback control (PID) to compensate for spectral shifts due to temperature changes or lumen decay of the LEDs. Both methods can be used independently, but only a combination of them (which uses the output of the first method as an initial guess for the second) offers fast computational times and high spectral accuracy and precision. Computation times are important because these algorithms are intended to be executed on dedicated microprocessors integrated in the LED modules, often sharing scarce memory and processing resources. The results presented here are aimed to be universal and hold for different implementations of the light engine and any number of LED channels.

https://www.spiedigitallibrary.org/journals/Optical-Engineering/volume-58/issue-3/035105/Arbitrary-spectral-matching-using-multi-LED-lighting-systems/10.1117/1.OE.58.3.035105.pdf

Arbitrary spectral matching using multi-LED lighting systems

Here we present a model of self healing in which correlations between chromophores, as mediated by the polymer, are key to the recovery process. Our model determines the size distribution of the correlation volume using a grand canonical ensemble through a free energy advantage parameter. Choosing a healing rate that is proportional to the number of undamaged molecules in a correlated region, and a decay rate proportional to the intensity normalized to the correlation volume, the ensemble average is shown to correctly predict decay and recovery of the population of disperse orange 11-DO11 (1-amino-2-methylanthraquinone) molecules doped in PMMA polymer as a function of time and concentration as measured with amplified spontaneous emission and linear absorption spectroscopy using only three parameters that apply to the full set of data. Our model also predicts the temperature dependence of the process. One set of parameters should be characteristic of a particular polymer and dopant chromophore combination. Thus, the use of the model in determining these parameters for various materials systems should provide the data needed to test fundamental models of the underlying mechanism responsible for self healing.

A self healing model based on polymer-mediated chromophore correlations.

A strategy is reported to optimize lighting to reduce photochemical degradation of works of art and archival documents. The strategy revolves around improving luminous efficiency of the spectral profile to exclude light which doesn't contribute to brightness or color perception, while also trying to maintain color rendering. The work focuses on Old Master Drawings and designing filters for illuminants, but is applicable to the broad range of art and archival documents and the direct design of lighting without filters such as LED. A filter profile is identified which seems to be beneficial, or at worst neutral for all pigments measured. Underlying principles are identified: (1) The best luminous efficiencies arise from multiple band illuminants, and also improves as color rendering is sacrificed. (2) Protection of an object even late in its damage life can significantly extend its remaining life. (3) Protection of an object early in its life can possibly abate some of the light induced damage it may experience across its life, so early intervention in light protection may be advised. This report further goes on to suggest approaches to further enhance the protection, including tailoring the spectral dependence of appearance change. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010

Lighting the world's treasures: Approaches to safer museum lighting

Photo-cleavable N-acyl-7-nitroindolines serve as a tool for the acylation of various nucleophiles. The mechanism by which the acylating species, the nitronic anhydride is formed, is not well understood. Reported here is a semiempirical AMPAC study of the reaction pathway in the ground and excited states. Results suggest an as yet experimentally unobserved ground state concerted suprafacial 1,5-sigmatropic shift pathway for the formation of the nitronic anhydride. The previously experimentally observed excited state pathway is considerably more complex. A concerted antarafacial shift is expected. However, on the S1 (lowest singlet excited state) manifold, the reaction appears to involve a shallow intermediate before proceeding by a hypothesized S1 to S0 (ground singlet) state crossing to the transition state for the concerted S0 shift, from which it likely proceeds onto a suprafacial shift to the nitronic anhydride. Triplet state behavior is explored and this system may possess a conical intersection of S0/S1/T1 potential energy surfaces. Further results explain the reactivity of the nitronic anhydride toward nucleophiles, as well as its susceptibility to protons, providing a complete mechanistic picture to explain the reaction behavior found by us and others.

Photoreactivity Of An N-Acetyl-7-Nitroindoline - Unraveling The Mechanism By Computation

The photochemistry of the self-healing chromophore Disperse Orange 11

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Nathan J. Westfall

Author Tools

Chat about Author

Papers

Lighting the world's treasures: Approaches to safer museum lighting

Photoreactivity Of An N-Acetyl-7-Nitroindoline - Unraveling The Mechanism By Computation

The photochemistry of the self-healing chromophore Disperse Orange 11