Noel; Not having read the instructions or being familiar with the
camera he mentioned I may be going out on a limb. But I’m stepping
Traditionally a gray card is for setting an exact exposure not white
balancing the camera. Although I suppose it would work - the card
is supposed to be a neutral gray (meaning equal blend of red, green,
and blue colors).
The tricky thing about camera exposure reading and what many people
don’t realize is that the camera makes an assumption. It assumes
that all things being in the metered zone reflect back 18% of the
light that hits it. Has an 18% reflectivity. The gray card is
selected because it has this 18% reflectivity and therefore gives
your meter a “correct” exposure.
The cards, like I said, should reflect back all the light equally so
it could be used as a white balance card. Only trouble I can see is
if the card was not a neutral color or there was not a lot of light
in the first place.
If not a neutral gray the white balance will be skewed to one color
or another. Not a problem if you can adjust it afterwards in
Photoshop or some other computer program. Make it look appealing.
If there is not much light you may run into a problem with the meter
not reacting the same to all the colors. Don’t think it would be a
problem, but if a real cheap metering mechanism was used it might
react different to different colors of light when the electrical
impulses get low.
I don’t do photography any more but work in video now. We’ve had to
deal with white balancing for a long time now. And before that with
movie film. Although that was dealt with using filters on the lights
or on the camera lens and using light color temperature meters. Some
reading two colors, the better ones reading all three.
I would not spend the money for a gray card to white balance and
being that we use a TV monitor or a vector scope/ waveform monitor to
set our exposures we generally don’t use it in video either.
We do white balance and there are white balance cards out there if
you insist on getting one. Porta-Brace in Vermont has them. But the
easiest thing is to just grab a sheet of 8 1/2 x 11 paper. There is
usually some lying around somewhere. Try not to use a brightened
paper (brighteners work by reflecting more ultraviolet light back).
It doesn’t register as a color but the eyes are sensitive to the
increased “intensity” and the camera may also be affected.
In a pinch a T-shirt or white blouse will work for a color balance.
The differences usually don’t make that much difference. I try for
consistency. Try to always use the back of the script to get the
On some cameras there may be a filter that has to be rolled into
place. Different filters are used for daylight (sun & HMI lights) or
tungsten lamps (normal type lights).
Fluorescents are different too, and your camera should tell you
which type to use. Many fluorescents will need additional filtering
also to make up for deficiencies in the electromagnetic spectrum (of
which light is the visible part - at least for human; many animals,
insects, and birds see colors differently than us).
I guess dogs only see black and white, with a tinge of red. Bees
and many insects see down into the ultraviolet. Some reptiles can
see infrared. Pigeons can see polarized light. Many lower animals
can only see light/ dark or not at all.
Getting back to gray cards and exposure. The exposure meter assumes
everything it sees is 18% gray and tries to make it that “color”.
If you photograph snow, white sand, or a white piece of paper the
camera will make it 18% gray. Same if you photograph coal or a crow
- the camera wants it to be gray. So if you are photographing things
that are not normal, you have to think for the camera and adjust the
exposure. For white you must open up the exposure (add light) about
two stops. For black close down 1 1/2 to 2 stops. Let experience be
Remember, you are smarter than the camera - all advertising aside.
They are lying to you.
Jealous of Judy in Kansas and her storm warnings.