Lab lighting

Lynn Campbell <lynn.campbell [at] ccc__govt__nz> writes

>I have a question on the use of daylight for retouching of oil
>paintings. We are in the process of planning for a new provincial
>art gallery and there has been some discussion on the use of an
>oriel window which is made up of glass.  This juts out from the
>building on the first floor to the outside so that people can view
>the conservator at work. I have a few concerns regarding this:
>
>    1.  Light coming from all directions.
>        Wouldn't this affect the painting and the retoucher?
>    2.  Wouldn't there be lots of radiant heat?
>    3.  Who wants to be on show in a glass case?

I am sorry to hear that you or some poor painting conservator will
be made to suffer an impossible working environment due to some
misguided ideas of presumably the museum director.  Boiled in
summer, frozen in winter. Yes, people are fascinated by conservators
at work but viewing someone at a distance where all you can see is
the back of them  with their hand moving and no dialogue is a
misunderstanding of the needs of the public.  It would be like
watching TV with the sound turned off.  People want to hear about
what you are doing and it is much better to organise studio tours
where the conservator talks face to face with people than set up a
situation which is pointless for the viewer and makes treatment
difficult for the conservator. One of the large conservation
workshops where I work is set up with a large viewing window but
after the first glance there is nothing further to offer and no-one
lingers. People who suggest such ideas also forget that at least 50%
of your time will be spent elsewhere. Doing structural treatments on
the table , paper-work at your desk, meetings or whatever. You
should contact the Liverpool Conservation Centre, UK for some
sensible ideas on how to present conservators to the public.

As far as the logistics of daylight and large windows go, daylight
would be the light source of choice. Northlight is the desired
source but not every window faces north. However there should be no
question of sun ever shining through it and onto the painting--if it
does you will need blinds to cut out the excess light , ultra violet
radiation and heat. You may wish to be able to black the window out
completely for U.V. examination. Also you are likely to need
additional artificial light to supplement the daylight for much of
the year (and for those dark coloured retouchings). These should be
colourmatching (fluorescent) tubes which mimic the colour of
daylight. We mostly use lights supplied by C.L.E. Designs Ltd. In
practice this means your painting will be several feet away from any
window to allow for the easel , you and your seat, your trolley
light,your work trolley and anything else you might have like a
microscope stand or even room to stand up!

The British standard for colourmatching states you need 2,200 lux to
fall on the surface where you are colourmatching. I work in front of
a 20 ft northlight window but on a dull day the lux may be as low as
70 so artificial lights are essential. There also is noticeable heat
loss through it in winter despite the central heating radiator
underneath, but pulling the blinds helps.

                                  ***
                  Conservation DistList Instance 13:7
                   Distributed: Monday, July 12, 1999
                        Message Id: cdl-13-7-002
                                  ***