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NORDIC LIGHT & COLOUR
129
advantages and disadvantages, starting with the LED, next the
fluorescent light bulbs, then the halogen bulb and finally the
fluorescent tube. Color rendering capabilities are described for
each technology, and is categorized as one of six things one is
assured a certain quality of, when buying a light bulb tagged
with the Go’Energi Label which is DESTs own voluntary energy
label. It states that the value of Ra will be at least 80 with the
Go’Energi label
, which complies with the DS 700 standard for
office lighting. But the pamphlet does not explicate the Ra
value, and it does not give any directions to how one would be
able to evaluate it. The pamphlet does not demonstrate the
various spectral distributions either, in spite of Ra values being
closely connected to the spectral distribution.
Schematics comparing sockets for each type within each
source is given as well as a floor plan indicating what sources
fit which room the best. This is very much in line with the
pedagogical touch of the previous pamphlets (DEST, 2004) and
(DEST, 2008); however everyday life practices connected to
the various rooms are much less emphasized than in previous
pamphlets.
Interestingly, in spite of having emphasized the potential of
LEDs in terms of color rendering, halogen sources are still
recommended in the floor plan, for kitchen and bathrooms,
indicating that color rendering capabilities are still better for
halogen sources. This seems a bit contradictory in terms of
some of the aspects accentuated elsewhere in the pamphlet,
and in the pamphlets (DEST, 2009) and (DEST, 2010). Although
it is important to remember that some of the pamphlets may
have another audience (mainly (DEST, 2009) and (DEST, 2010))
it is also important to note that all pamphlets are equally as-
sessable on the The Danish Energy Savings Trusts webpage.
The shifting focus and lack of strict consistency in the pam-
phlets may cause confusion for some readers.
Lighting - a matter of quality and everyday life or efficiency
and technical assessments?
As can be seen from the short assessments, all the pamphlets
- to some extent or another - describe and deal with the matter
of color rendering. But it is done in various ways, with more or
less emphasis on the technical color rendering capabilities,
and in some of the pamphlets the color temperature seems to
play a greater role.
Generally, the matter of
when good color rendering is required
is
delimited to situations where there is either a need for rec-
ognizing details (handcraft, or putting on make-up) or when
preparing food. In terms of general lighting, particularly in the
later versions of the pamphlets, energy efficiency and costs
seems to be of higher, or at least more distinct, priority. Fur-
ther, focus on the everyday life practices connected to certain
rooms and thereby certain light sources becomes decreas-
ingly significant in the pamphlets, where as technical aspects
and explanations gain an increasingly bigger role. Focusing on
the technical aspects and explanations is probably due to the
conception of having a technical and scientific language would
ease the communication and understanding of the workings of
the different technologies.
Product information corresponding to guides?
No matter the reason for focusing on the technical and ‘mea-
surable’ aspects of the various lighting technologies, the way
this kind of information is emphasized and presented is in itself
interesting.
Below is a series of pictures, that have been taken during the
fall 2012, presenting the information one would be able to get
from the package when buying a bulb that is
typically
available
in a Danish
local supermarket
. The information on color render-
ing and color temperature has been emphasized with red and
blue ovals for the purpose of this paper.
As presented in the assessments, the guides’ point to the no-
tion of Ra in terms of ensuring a color rendering quality, and
that one should look for the notion Ra on the packaging. But
this may not be obvious for the domestic user, especially since
it is not always present on the packaging. As can be seen from
the pictures, the color rendering capabilities of various light
sources are indicated through the abbreviation CRI (Ra),
if at all.
In the pamphlets, LEDs are (mostly) promoted as having ‘good’
color rendering capabilities, and they are often promoted as a
better alternative to the A-bulb. However, the pamphlets also
generally state that many LED’s have Ra values of 80 (that as
mentioned is the legislated minimum requirement) which cor-
responds to what many compact fluorescent light bulbs comply
with as well (see for instance p 22 in (DEST, 2012)). This is in-
teresting as compact fluorescent light bulbs are often criticized
for their poor color rendering capabilities.
The Color Rendering Index and its contested development
The reasons for this somewhat contradictory information may
be multiple, but one of them could be due to the increasingly
disputed nature of the CRI itself;
Even if the CRI Ra value is given, it may not even ensure an
actual corresponding color rendering. That may be important
for why the color rendering is difficult not only to guide for, but
also to present as brief, simple information (for instance sym-
bols). According to Rea and Freyssinier-Nova (2008), CRI is but
one measurement for establishing color rendering capabilities
of light sources. In fact, the CRI measurement only says some-