Dr. Michela Radis Profile

Dr. Michela Radis

at Istituto Nazionale di Ricerca Metrologica

SPIE Involvement:

Author

Publications (4)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 11 July 2017 Paper

Optical characterization of natural protective varnishes and their influences on perception of painted samples

M. Radis, P. Iacomussi, C. Aghemo, G. Rossi

Proceedings Volume 10331, 1033104 (2017) https://doi.org/10.1117/12.2270310

KEYWORDS: Metrology, Light sources and illumination, Bidirectional reflectance transmission function, Glasses, LED lighting, Light emitting diodes, Material characterization, Optical properties, Ceramics

Read Abstract +

Interdependence between color and gloss is a concept well-known by artists, especially by old masters, but is not usually considered in material characterization. Indeed, measurement methods and definitions consider these two attributes individually. This research investigates how the available measurement methods for gloss and color (saturation) fit with corresponding perceptual qualities, glossiness and saturation. The definitions of both measured quantities, as well the measurement methodologies, were developed for reference materials (ceramic tiles for color and dark glass specimen for gloss) not representative of artwork materials and do not consider observation conditions similar with those adopted during exhibitions. The prediction of material appearance is recognized as one of the most important challenges in applied metrology, because appearance is the key to achieve effective exhibitions and consumers choices. The results of this study highlight that the two perceived qualities are mutually related, as well the measured quantities: gloss and saturation mutually interfere and the measurement methods and quantities are not uniform with the perceived qualities and the colorimetric coordinate C* no longer describes the perceived saturation.

Proceedings Article | 30 June 2015 Paper

Optical characteristics and visual appearance for artwork materials

M. Radis, P. Iacomussi, C. Aghemo

Proceedings Volume 9527, 95270J (2015) https://doi.org/10.1117/12.2184752

KEYWORDS: Light emitting diodes, Visualization, Light sources and illumination, Lamps, Reflectivity, LED lighting, Visual optics, Luminescence, Cultural heritage, Colorimetry

Read Abstract +

The aim of this study is to evaluate experimentally how well available metrics are able to evaluate how lighting sources affect the perception of visual attributes of artworks exhibited, providing useful indications for works of art exhibition designers. The study considers objective investigations on optical material properties (i.e. spectral reflection factor) compared to subjective tests on colour attributes evaluation of artworks lighted by common lamps (incandescent and fluorescent lamps) and LED lighting sources.

Commission International Eclairage (CIE) developed several mathematical methods to predict colour rendering of lighting source, as well visual attributes of materials, but are only an approximation of the material appearance: too many parameters of influence, subjects expectancy included, influence the appearance. In artwork exhibition visual appearance is of fundamental importance and currently no reliable and robust appearance model is available. Comparing objective evaluations and subjective results for lighting set up comparable to works of art exhibition, will provide useful indications on the applicability of colorimetric calculation to artwork exhibition when LED are involved.

Visual attributes (hue, saturation, brightness…) of six different colours under LED and not-LED sources at the same Correlate Colour Temperature were compared to the associate objective characteristics calculated from the spectral reflectance.

The results show that the perception of visual attributes differs from objective data when SSL sources are involved and when colours are perceived in complex samples: in some cases the visual system is not coherent with the suggestions arising from the calculations.

Proceedings Article | 30 June 2015 Paper

Spectral characterization as a tool for parchment analysis

Michela Radis, Paola Iacomussi, Giuseppe Rossi

Proceedings Volume 9527, 95270N (2015) https://doi.org/10.1117/12.2184724

KEYWORDS: Skin, Manufacturing, Ultraviolet radiation, Statistical analysis, Databases, Reflectivity, Collagen, Visible radiation, Analytical research, Tolerancing

Read Abstract +

The paper presents an investigation on the correlation between spectral characteristics and conservation conditions of parchment to define a NON invasive methodology able to detect and monitor deterioration process in historical parchment without the need of taking small samples. To verify the feasibility and define the most appropriate measurement method, several samples of contemporary parchments, produced following ancient recipes and coming from different animal species, with different degrees of artificially induced damage, were analyzed. The SRF and STF of each sample were measured in the same point, before and after each step of the artificial ageing treatment. Having at disposal a parchment coming from a whole lamb leather, allowed also the study of the correlations between the variations of SRF – STF and the intrinsic factors of a parchment like the variability of animal skin anatomy and of manufacturing. Analyzing different samples allowed also the definition of the measuring method sensitivity and of reference spectrum for the different animal species parchments with accuracy limits. The definition of a reference spectrum of not damaged parchment with acceptability limits is a necessary step for understanding, through SRF – STF measurements, historical parchments conservation conditions: indeed it is necessary to know if deviations from the reference spectrum are ascribable to damage or only to parchment anatomic/production variability. As a case study, the method has been applied to two historical parchment scrolls stored at the Archivio di Stato di Torino (Italy). The SRF - STF of both scrolls was acquired in several points of the scroll, the average spectrum of each scroll was compared with the reference spectra with the relative tolerance limits, recognizing the animal species and damage alterations and demonstrating the feasibility of the method.

Proceedings Article | 16 March 2015 Paper

Goniometric and colorimetric properties of paints and varnish

P. Iacomussi, M. Radis, G. Rossi

Proceedings Volume 9398, 93980N (2015) https://doi.org/10.1117/12.2077710

KEYWORDS: Light sources and illumination, Reflectivity, Optical properties, Coating, Ions, Analytical research, Visible radiation, Reflection, Resistance, Statistical analysis

Read Abstract +

The spectral reflectance of different samples of three different hues, (red, green, blue) with four different protective varnishes was measured in 8/d condition and with a goniometer equipped with a spectrometer. The samples are representative of hue and varnishes typically used in works of arts, the characterization was performed to test how the different gloss finishing induced by transparent varnishes affect the spatial distribution of the luminance coefficient in typical lighting arrangements for exposition of works of art. Nowadays the most used transparent protective varnishes are matt or glossy, natural or synthetic. The choice within them is usually made looking at mechanical, chemical (also in term of removal) and protective properties. Varnishes optical properties investigation on saturation and gloss alteration of the perceived artifacts are not usually investigated. Expected results of this research include: analysis of influences on color appearance of protective varnish according to the condition of illumination and observation, suggestion of new additional criteria for varnish selection and lighting set up exposition and reliability of 8/d measurements condition, that is a typical measurement set-up of portable instruments. Our results showed that natural varnishes are more able to change the gloss of the surfaces than synthetic ones, because the shape and intensity of the specular peak for glossy and matt natural varnish are very different. Both synthetic and natural varnishes have different behaviors at 30° or 60° light incidences: at 30° of incidence all samples have smaller variations, while at 60° of incidence the variations are larger, and for some samples the achromatic point is reached.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years