Re: 5000° K Full Spectrum Lighting
Re: 5000° K Full Spectrum Lighting
- Subject: Re: 5000° K Full Spectrum Lighting
- From: Richard Frederickson <email@hidden>
- Date: Wed, 27 Feb 2008 09:48:04 -0500
Karl, Danny, and the list,
Thank you for your thoughtful comments. A little
more background explanation may be in order.
I'm not trying to turn our illustration studio
into a giant D50 view box. We have a GTI viewer
with our scanning workstation and any critical
color/prepress color judgements are done using
that viewer. I visited a vendor of ours, and
their entire facility is 5000° K--using
everything from fluorescent tubes in the
office/design areas to mercury vapor in the
production warehouse space.
I'm simply interested in providing our graphic
designers and photographers with the most
appropriate working environment as possible for
the overall space and for general black and white
and color work. I think I've won the argument for
calibrating everyone's monitors on a regular
basis (~D50), as well as neutral gray furnishings
and walls. The last piece of the viewing
environment to address, then, is the general
illumination.
We are located in a government facility, which
mandates the use 32 watt "energy efficient"
lights and are currently using warm white
fluorescent tubes. My instinct tells me that the
5000° K "full spectrum" lamps should be better
than the 4000° K we're getting from our
lowest-bid office lamps.
Employee comfort and avoiding eye fatigue is a
major concern--so I don't want to turn the studio
into a bat cave. I do have some ability to
moderate the lighting within the scanning area,
and it will be at a lower level of illumination.
How much is enough, and where does it become too
much is the main concern of my boss.
Any of your insights are greatly appreciated,
Richard
Hi Richard, Danny,
Am 26.02.2008 um 23:33 schrieb dpascale:
Richard,
Do you intend to illuminate the area around your monitors with 5000 K light?
ThatZs whaZs recommended in ISO3664 and 12646
If yes, are your monitors also at D50? (or somewhere between D50 and D60)
again, ISO 12646
Do you intend to compare your prints against
your monitor? If not, then buy these low cost
tubes and keep the ambient level low (100 lux
recommended). If yes, read what follows.
Even lower, if you want a good comparison, your
viewing light must e 500 lx ± 125 lx (ISO3664),
this requires a monitor luminance of 160 cd/m2
(± 40) and your ambient light must be below 64 x
and should be below 32 lx.
The required illumination for correct viewing
assessment, 500 lux+, is too high to be used as
ambient (even your 390 lux is way too high for
many).
This is absolutely correct, because the ambient
light drastically reduces the contrast ratio on
your monitor.
Thus, you need a separate, somewhat confined,
viewing booth. You will also need to adjust
your booth light output so that the luminance
of the viewed print matches your monitor
luminance (typically 100 to 160 cd/m2).
with 100 being too low, the range is 120 to 200 cd/m2)
If you compare your prints under a 5000K lamp
near your monitor, your monitor better be at
5000K also. If your monitor is "far away" from
your viewing booth, a D65 calibrated monitor
will be OK.
If you critically compare printed material with
printed proofs, without a need to compare the
prints against a nearby monitors, then a room
full of fluorescents at 5000 K, with much more
than 500 lux, is the way to go (2000 lux is
recommended, which is quite bright !).
but typical for a standard viewing booth.
You better use less of the more expensive
fluorescents and place them at select locations
where they do not interfere with the monitors
(a booth, or a low hanging fixture is
preferable to a ceiling fixture). And keep all
the other lights off (the window shades also if
applicable). The indirect illumination from the
booth areas should be enough to work
comfortably. If not, individual desk lamps
should be used when required.
Keep in mind, though that the lamp fixtures -
reflectors, deflectors - also have an influence
on the spectrum. So, a professionally made lamp
with certified (close to) D50 light would be the
first choice. BTW, D50 is not a full, smooth
spectrum, but a specified spectral curve (quite
jaggy) that cannot be technically reproduced
(within reasoable effort). 5000K Planck is a
smooth curve.
And, finally, to add to what Andrew mentioned,
fluorescents are fluorescents (!), even the
best ones are not perfect, imagine the second
tier...
Danny Pascale
email@hidden
Best,
Karl Koch
----- Original Message ----- From: "Richard
Frederickson" <email@hidden>
To: <email@hidden>
Sent: Tuesday, February 26, 2008 4:14 PM
Subject: 5000° K Full Spectrum Lighting
My manager and I have had an ongoing
discussion for some time now regarding whether
or not 5000° K lighting is justifiable in our
illustration/photography workstation areas. We
do some prepress work and I have a GTI viewer
at our scanning workstation. Most of our
material is printed in-house (e.g., scientific
posters) and our color is important, but not
critical.
The folks at GTI quoted me a price of $23 a
lamp, which my boss absolutely will not go
for. I've seen a number of "Full Spectrum"
lamps on the market that are the same color
temperature for as little as $6 a tube, and
I'm thinking that something is better than
nothing. Am I right in this line of thinking
and how prevalent is full spectrum lighting in
the real world?
Also--beyond color fidelity issues--are there
any additional benefits documented about
working in this lighting environment?
The corollary question is how bright should
the working environment be? I took few quick
measurements around the office with my eye-one
found a value of 74 Lux at the monitor is
about 390 Lux at the keyboard and quite
comfortable to work in.
Many thanks for your thoughts,
Richard
--
Richard Frederickson (Contractor)
Scientific Publications, Graphics & Media (SPGM)
Advanced Technology Program, SAIC-Frederick, Inc.
National Cancer Institute at Frederick
Post Office Box B
Frederick, MD 21702
Phone: (301) 846-1546
FAX: (301) 846-6563
email@hidden
NOTICE: This communication may contain
privileged or other confidential information.
If you are not the intended recipient, or
believe that you have received this
communication in error, please do not print,
copy, re-transmit, disseminate, or otherwise
use the information. Please indicate to the
sender that you have received this e-mail in
error and delete the copy you received.
Visit us at http://web.ncifcrf.gov/spgm
Send us files at http://web.ncifcrf.gov/spgmfiledrop
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden
--
NOTICE: This communication may contain privileged
or other confidential information. If you are not
the intended recipient, or believe that you have
received this communication in error, please do
not print, copy, re-transmit, disseminate, or
otherwise use the information. Please indicate to
the sender that you have received this e-mail in
error and delete the copy you received.
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden