Welcome to Filmmaker IQ.com
today we're going to be looking at the psychology and science
behind color temperature
The way we perceive color is greatly influenced by
our cultural understanding
we all grew up learning that fire is hot and ice is cold
therefore reading orange are warm colors while blue and cyan are cool colors
this association in our mind is so strong that filmmakers can actually
invoke a sense a
temperature just by the color palette the use in their films
take for example Spike Lee's 1989 film
Do the Right Thing
Doing the ying and yang the hip and hop
the stupid fresh thang, the flippity flop
HOWL
I have today's forecast for you HOT!
The film beautifully photographed by
Ernest Dickerson is awash in yellows oranges and reds
invoking the heat of a long hot day in Bed Sty
a neighborhood of Brooklyn New York the urban cityscape is a
vibrant community full of life he diverse neighborhood where
everyone knows and accepts each other but things are boiling under the surface
Old hurts are being remembered tensions build like a pressure cooker
and things are about to explode. Contrast this with the Coen Brothers 1996 film: Fargo
photographed by Roger Deakins Fargo was dominated by
blue and gray even the snowy white exteriors
cast the cold bluish light so that the weather itself
mirrors William H Macy's character's icy soul
It's a constant reminder of the frozen landscape surrounding him
and his inept henchmen. Both these films utilize production design to
accentuate hot and cold
but they also push the feeling of temperature using creative applications
white balance and color temperature
When we talk about color temperature
we're talking about the property white light. White light is really a creation of our own minds
is no color white on the light spectrum the color white confounded people for
thousands of years it took
Isaac Newton in the late 17th century to finally demonstrate using a prism
that white light was really a mixture of all the colors of light
To precisely define the proportions of different colors
in time that two temperature well that would have to wait till 1900
and Planck's law. Max Planck was a German physicist commissioned by
German manufacturers to figure out the best temperature to heat the filament of a light bulb
for maximum visible light output with the least amount of electricity
He tried to tackle the problem using contemporary theories of the time
but the equations just we're matching up with his experimental data
So he devises own theory which would later become
Planck's law which describe the type of electromagnetic radiation generated by
theoretical black body at a given temperature
Ok... let's back up and explain that. You see...
everything in the Universe that has a temperature above absolute zero
gives of some sort of electromagnetic radiation whether that's infrared,
visible light, ultraviolet, X-ray, and everything in between
Even you and I give of radiation but it's in the form of very low energy
infrared which we commonly call heat that's what IR night vision goggles pick up
as you increase the temperature something you give off more and more
heat right or electromagnetic radiation if you get hot enough
it will start to glow that's what's giving of radiation in the form up
visible light continue raising the temperature
and the glow will go through a very specific
range of colors which is mathematically described
by Planck's law and this is what we mean we talk about color temperature
is the color white that would correlate
with the color of light have a theoretical blackbody
at a particular temperature so what was the temperature that Max Planck finally
settled on as the ideal for Les Paul it was 3200 Kelvin
which is still with us today in the form of incandescent lighting
in the filmmaking world this number is also known as tungsten balance
the other common source of light is the Sun
the sun's surface temperature is about fifty eight hundred degrees Kelvin
but someone has to be filtered through our atmosphere
and can range anywhere from a correlated 2800 degrees Kelvin at Magic Hour
or even up to 6500 degrees Kelvin on an overcast day
for most applications 5600 degrees Kelvin
the color of light on a clear mid-day is what we mean by
daylight balanced. Now these are two examples of light being created by hot
objects that pretty much follow Planck's law
but what about alternative lighting how do they generate white light.
Fuorescent lights use a tube coated with phospherous
filled with an inert gas and a tiny amount of mercury. When you turn it on
light is created by the fluorescence of the phosphorus and the tube
unlike hot object admit light in all frequencies
as described by Planck's law fluorescence tend to spike
only at certain frequencies mainly the primary colors red green and blue:
This still looks like white light to us even though it's missing
a lot of the frequencies in between red green and blue
now for cheaper bulbs manufacturers will sometimes
increase the amount of green because it gives the bulb a
brighter appearance being that green is right in the middle of the visible spectrum
Unfortunately though this can give footage shot under cheap fluorescent lighting
a green tinge. Manufacturers do offer florescent bulbs
of different color temperatures and they do this by mixing in different chemicals
into the phosphers.
for photography and cinematography they add more colors into the bulb output
to get a fuller spectrum of colors so you're not just limited to red green and blue
there's yellow and magenta and other colors in there.
That way subjects look more natural
look for bulbs that have a higher color rendering index
or CRI. A CRI of a hundred is full spectrum like the Sun
but for best results use flourscent bulbs rated 90 or higher
LED lighting is the newest alternative to incandescent lighting
they can also present in many the same issues as fluorescence
when it comes to a limited spectrum the color of an LED is based on the material
used in a diode the light emitting diode there are several ways to get white light
either by using phospers or by blending different colored LEDs
together in a single fixture
some fixtures even have the ability to dial in your color temperature
by mixing the intensities have different colored LEDs
When you white balance your camera you're essentially telling the camera what color
temperature you want to use
as a base for white. Now there are traditionally two important numbers you should know by heart.
we've already touched on them: 3200 Kelvin
which is the temperature of tungsten lighting and 5600 Kelvin
which is the temperature of sunlight on mid-day on a clear day
many cameras have these as presets as walls
other common lighting scenarios.
Almost all cameras have the ability to set a custom white balance using a gray card
or white card this is done by filling the frame with something gray or white
and then pressing the white balance button which zeros the value so that the color
it's in front of the camera is deemed as neutral
Now for much better control professional cameras have the ability to dial in a
specific number for your white balance. This is
really great for dailing in the look that you want
if you want a warmer tone just push the color temperature higher
a cooler tone push the color temperature lower
if you're shooting with a camera that shoots any raw format
well you can save your white balance decisions until post
A common color temperature problem that pops up
is when you have competing light sources in the same shot
have different color temperatures. Like say you're shooting
indoors near a window and using tungsten light
Now if you white balance 5600 Kelvin
the indoor light will look really orange if you balance to 3200 Kelvin
light from the window all look really blue
to get them to match you need to use gels
either cover the entire window with CTO
cautions orange gel or more easily just cover your light
was CTB color temperature blue gel
It's also worth mentioning here that dimming of tungsten lights will lower their color temperature
and make them look warmer after all the filament isn't getting the same amount
of current
therefore it's not burning as hotly so
by Planck's law they will be a lower color temperature
now there's no need to adhere rigidly to
any of these numbers were giving out here just because were shooting here
under tungsten lighting doesn't mean we have to set the camera
precisely to 3200 Kelvin or that we can't
blended different color temperatures in a single shot and mix cold
outdoor lighting with warm interior lighting as long as it serves an
artistic purpose
but understanding the mechanism of color temperature and
why it works it will give you the tools to solve artist to challenges when
you're on set
these tools go way back: from our earliest moments huddle around a warm
life-giving campfire to Isaac Newton messing around with pieces of glass
to Max Planck trying to figure out how hot a light bulb should burn
in founding the basic tenets of quantum mechanics in the process
each step furthers our understanding and enrichens our history
So use it - go out there and make something great
i'm John Hess and I'll see you at Filmmaker IQ.com