photobiologyFilters-package: photobiologyFilters: Spectral Transmittance and Spectral...

In aphalo/photobiologyFilters: Spectral Transmittance and Spectral Reflectance Data

photobiologyFilters: Spectral Transmittance and Spectral Reflectance Data

Description

Spectral 'transmittance' data for frequently used filters and similar materials. Plastic sheets and films; photography filters; theatrical gels; machine-vision filters; various types of window glass; optical glass and some laboratory plastics and glassware. Spectral reflectance data for frequently encountered materials. Part of the 'r4photobiology' suite, Aphalo P. J. (2015) \Sexpr[results=rd]{tools:::Rd_expr_doi("10.19232/uv4pb.2015.1.14")}.

Details

This package contains transmission spectra for different types of optical filters and filter-like objects. These spectral data are NOT normalized. In most cases they have been obtained from sheets of the standard thickness supplied by sellers. Metadata is stored together with the spectral data, when available, it includes thickness, an approximate estimate of Rfr (contribution of reflectance) and whether attenuation by the filter is based on reflection, absorption or both. Beware that when attenuation is by absorption in the body of the filter, thickness has a strong effect on the wavelengths at which Tfr = 0.5 is reached for a given material. Be also aware that some of the data are for total transmittance and some for internal transmittance. Depending on the type of filter, spectral transmittance depends more or less strongly on the angle of incidence of radiation. All measurements included have been done with a angle of incidence that deviates at most by a 10 degrees from zero (light beam perpendicular to the surface of the filter). Additional data is provided in the documentation for different objects, and metadata is also stored as attributes in the individual spectral objects. When metadata are available, estimates of spectral transmittance for different thicknesses can be approximately computed for filters based on ionic or absorptive glass or plastic. The same is true for the conversion between total and internal transmittance if Rfr is available. There are also filters based on surface reflection or absorptive layers on the surface or encased. Some filters even use a combination of these approaches.

Total spectral transmittance for climate screens used in agriculture and horticulture is also included.

In addition to transmittance for semitransparent materials, the package also contains data on the refractive index as a function of wavelength, for several different materials. These data allow the estimation of spectral reflectance for these materials.

Spectral reflectance data is included for several common metals and for natural and man-made surfaces (relevant to remote sensing).

Transmittance data are included for:

• The whole catalogue of Schott optical filters (official data supplied by Schott for inclussion in this package).

• Most of the catalogue of MIDOPT filters (official data extracted from dowloaded files from supplier, reproduced with permission).

• Clear glass as used in windows (as used by CIE, from data file downloaded from CIE's server.)

• Several types of Plexiglas from Evonik measured at our lab.

• Other types of plastic sheets supplied by Foiltek Oy and Etola Oy, measured at our lab.

• Plastic films from McDermit and Courtaulds, measured at our lab.

• Several types of theatrical 'gels' from Lee, Rosco, and Formmatt. Some measured at our lab and others data digitized from manufacturers' catalogues.

• Films used as greenhouse cladding from BPI Agri/Visqueen, XL-horticulture and generic, measured at our lab.

• Various filters used in UV, VIS and IR imaging and photography.

Warning!

Except for those from Schott and MIDOPT, none of the spectral data included in this package are "official" specifications. In all cases data are only for information, as even suppliers refer to the data provided as typical. Spectral transmittance depends on the measurement conditions, and, even more importantly, among individual production batches of filter materials. Spectral specifications are usually given as reference values. Both glass and plastic filters also age: their spectral properties change as a result of exposure to radiation or the gases in the atmosphere. Aging is in some cases fast. Another point to keep in mind is that some filter suppliers, for example Rosco, have changed the spectral transmittance of some filters over the years without changing the code or name under which they are sold. In other words, the data provided here are not a substitute for actual measurements of transmission spectra of the filters actually used in a given piece of scientific research. For less demanding situations the data are in most cases useful, but good agreement with measurements on other batches of filters of the same exact type should not be expected, specially for materials not intended to be used as optical filters.

Note

This package is part of a suite of R packages for photobiological calculations described at the [r4photobiology](https://www.r4photobiology.info) web site.

Author(s)

Maintainer: Pedro J. Aphalo [e-mail] (ORCID)

Other contributors:

• Titta K. Kotilainen [e-mail] (Contributed data) [contributor]

• T. Matthew Robson [e-mail] (Contributed data) [contributor]

• Ricardo Hernández (Contributed data) [contributor]

• Tania de la Rosa [e-mail] (Contributed data) [contributor]

• Riitta Tegelberg [e-mail] (Contributed data) [contributor]

• Andreas Albert (Contributed data) [contributor]

• SCHOTT AG (Contributed data) [contributor]

• Midwest Optical Systems, Inc. (MidOpt) (Contributed data) [contributor]

References

Aphalo, Pedro J. (2015) The r4photobiology suite. UV4Plants Bulletin, 2015:1, 21-29. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.19232/uv4pb.2015.1.14")}.

See Also

Useful links:

• https://docs.r4photobiology.info/photobiologyFilters/

• https://github.com/aphalo/photobiologyfilters

• Report bugs at https://github.com/aphalo/photobiologyfilters/issues

Examples

library(ggspectra)
library(photobiologyWavebands)

# Total number of spectra in the package
length(filters.mspct)

# SCHOTT filters example
schott_filters
filters.mspct$Schott_OG530
filters.mspct[["Schott_OG530"]]
getWhatMeasured(filters.mspct$Schott_OG530)
filter_properties(filters.mspct$Schott_OG530)
cat(comment(filters.mspct$Schott_OG530))

# combining name (index) vectors
# blue glass filters
intersect(optical_glass_filters, blue_filters)
# green plastic films
intersect(plastic_films, green_filters)

# A Plexiglas sheet
getWhatMeasured(filters.mspct$Evonik_Sky_Blue_5C01_GT)
autoplot(filters.mspct$Evonik_Sky_Blue_5C01_GT)
transmittance(filters.mspct$Evonik_Sky_Blue_5C01_GT, Orange())
transmittance(filters.mspct$Evonik_Sky_Blue_5C01_GT, NIR())

# Asphalt
autoplot(materials.mspct$construction.asphalt, range = NIR(), w.band = NULL)

aphalo/photobiologyFilters documentation built on Feb. 28, 2024, 12:05 a.m.