From: boone@aloha.net (Boone Morrison)
Subject: Photography


I decided to answer George's photographic questions
in a post to all.  Not that I claim any great skills here, but I have done
a good bit of photo work and thought to at least offer some thoughts that
may apply.
If you have specific questions I will be glad to try addressing them as
well, just let me know.  Also, anybody else who can offer photographic tips
please do...we all need all the help we can get! :-)

Here is George Pierson's question:

I've been doing a bit of it in the last few years and generally use photo-
floods (2500 degree K, I think) with tungsten balanced film.  My question -
I model eastern n.g. so I have a lot of green in the background.  Hence my
photos, to my eye, often look too dark and the blue-green tones overwhelm.
Using more intense lighting helps but tends to wash out the lighter
colored areas like rock faces.  Plus the light is too harsh and the shadows
too dark and prominent.  What I'm after is more even and softer lighting
that still more or less evenly illuminates everything and has some of the
warmer tones more prominent.  My problems may also be exacerbated by
leaving the layout neon lights on while shoting.  I have not worked with
filters; the camera is usually a Canon AE-1 with a closeup lense; and I
have not worked with flash or light bounced off a reflective umbrella (the
basemoent is too cramped to use one effectively).  Any suggestions?
Thanks!!

End of Georges question:

First, I suspect that where he says "neon" he must mean "florescent"....or
at least so it seems.  Also, I suspect that the flood lights are 3200 K,
which is one of the two standard colors.

The following comments are premised on the use of transparency (slide)films.


To begin with, the key to getting good color is selecting a film/light
combination that will render colors as "natural".  Generally, films are
balanced for either one of two different light sources-"daylight" and
"artificial" (tungsten) light.  To get us all on the same page, it is
necessary to discuss light a bit.

1. The color of light is measured in "degrees Kelvin"....evidently a black
iron piece is heated to various temperatures (F) and at certain
temperatures it glows with light of various colors.  The cooler the
temperature, the more yellow the light...the hotter, the more blueish the
light.

2. "Daylight", for photographic purposes, has been determined to be 5500
degrees Kelvin at high noon.  So, the emulsions of "daylight" films are
formulated to render colors correctly under light of that color.  If you
take "daylight" film indoors and shoot photos with normal incandescent
lights the images will be quite yellow in overall coloration.  The film
cannot compensate, as our eyes do, for that shift in the basic color of the
light it is seeing.

3. "Artificial" or "Tungsten" light films have emulsions formulated to
render colors properly under light with a far greater amount of yellow in
it than true daylight.  Normally Tungsten light films are balance for 3200
degree Kelvin sources, such as the common #1 photoflood bulbs one can buy
at the camera shop.
If you try taking photos out doors with this film the results will be very
blue because the film is formulated to compensate for the yellow in
tungsten light.

4. "Blue" tungsten bulbs do give off light of 5500 degrees K, but their
color changes towards yellow rather rapidly and after about an hour of use
they will have shifted several hundred degrees warmer.

5. Electronic flash is "daylight" balanced, so one can shoot with daylight
films and get proper color rendition.

Sorry for the lecture, but we have to start on the same page to make the
rest of this make any sense at all.  :-)  Well, maybe  SOME sense...

One more nasty little element is called "color reciprocity failure"....this
refers to an odd quality in film emulsions by which, with long exposures,
there is both a change in the film sensitivity (ASA or DIN ratings) AND in
the rendition of colors.  Different films react differently, so the
compensation issue must be addressed for each film you plan to use.

I will give an example using my regular film, Fujichrome Sensia 100, 35mm.

With Sensia 100 exposures greater than about 12-15 seconds begin to cause
the film to render things with a greater emphasis on the greens.  A soft
green becomes rather intense and whites tend to demonstrate a slight green
tone...not what we want at all!  Also, with Sensia 100 after about the same
amount of exposure I have to begin increasing the time to get proper
results, otherwise the film is under-exposed.

Now, the crux of this whole question is "how do we light the layout so we
can photograph it and get "proper" colors"....

Here are several choices:

1. Use four foot, double tube florescent fixtures and equip them with GE
Chroma 50 bulbs, which give off light that is (as far as color film is
concerned) true daylight.  The daylight film sees the "proper" balance of
light and renders the colors "correctly" every time.  ANY OTHER FLORESCENT
LIGHT, EVEN IF IT CALLS ITSELF 'DAYLIGHT' WILL NOT DO...

This is what I use for overall illumination on my layout.  With my Sensia
100 rated at ASA 150 (my personal rating developed out of film tests) and
my 55 macro lens stopped down to f 32, the exposure is usually 8 seconds.
Under the time when both color and exposure reciprocity begin to enter the
picture.  The small f-stop gives me maximum depth of field.

The light from the florescents is quite smooth, shadows are not too harsh
and it is bright enough to allow reasonable exposures (see above).
Occasionally I will use a piece of foam core with aluminum foil spray-glued
to it as a reflector to put a bit more light into the shadows.  Since the
light is reflected from the correctly colored florescents, everything stays
in balance.

On other occasions I will use a single electronic flash to add "sparkle" to
the highlights, glints off of water, things like that.  My flash unit (a
Sunpack 550) has an adjustable flash intensity and I most often use it at
50% power.
My main exposure is reduced about 25% to account for the increase of light
from the flash.

2. Light the layout for work/viewing in any way you like and bring in
photofloods (32ooK balanced) for photography.  Use "Tungsten" balanced film
and you should have good color balance.

Shadow intensity control with these lights requires a bit of care.  The
rule of thumb is that the main light is one unit of illumination and the
"fill" light
(for the shadows) is 1/3 of that amount.  If you have the room this is
easily accomplished by putting the fill light three times the distance from
the subject as the main light (with the same wattage bulb)....or use a 500
watt for the main and a 250watt for the fill, with the latter about 1/3
farther away than the main.  The aluminum reflector can also be most
helpful here.  If the aluminum side is too bright, flip it over and use the
plain white card side for even more diffuse fill light.  You will be amazed
at how well this works.

3. Equip yourself with two or three good flash guns with adjustable
intensity, get a good flash meter and go for the all-electronic flash
approach.  In a real portrait studio they will have "focus lights" as a
part of the flash unit.  These enable you to see what the light from the
flash will look like (no other way to gauge this) and are turned off when
actually shooting.  Be prepared to pay the cost of at least two (maybe
three) good brass locos for this kind of lighting rig.

So, George, I suspect that having ANY florescents on during shooting may be
a big part of your color rendition problem.  You HAVE to choose either
daylight or tungsten light, and the regular florescents are neither.
Filters are made for supposedly correcting the florescent light balance,
but they never work well enough to satisfy me.  If you are getting only
minor shifts of color, you may be able to filter the camera to
compensate....Kodak makes a series of CC filters for this purpose.  They
are sold in many colors and several densitys for each color.  For example,
if I am getting a green shift in the photos I use a CC-10M, magenta filter
to pull out that green. This is getting pretty technical, but if you have
tried all the rest of it and are still getting such a shift, that is the
only way to correct it that I know.

Since you have the florescent fixtures, my suggestion would be to gradually
equip your layout with the GE Chroma 50 bulbs and be done with the problem.
The UV filters do not seem to effect the color balance and are a very good
idea since colors will fade over time (it does take a while, though).

Well, I hope that has helped George and not bored the rest of you.  My
apologies if it has been over long....

Aloha, Boone Morrison



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