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The one dollar photo "dome diffuser"

Most recent digital cameras have a manual “white balance” setting.
If my Nikon Coolpix 995 is typical, the term is a little misleading.
“White balance” actually requires that you buy a special grey card
to put in your lighting set-up, then aim the camera at it to read
the white balance and set it. When you turn the camera off, it will
revert to default. If you use the special card (then remove it and
take your shots), you should not need to shift the color afterwards.


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
color balance.

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
    your guide.

Remember, you are smarter than the camera - all advertising aside.
They are lying to you.

Jealous of Judy in Kansas and her storm warnings.

Hi, Eric,

Thanks for the interesting “illumination” of the subject of exposure
and white balance. As it happens, my wierdo camera requires
(instructions) a grey card for “white” balance. With photofloods,
shoots everything yellow otherwise. If mine (Nikon Coolpix 995) is
the only model that is that way, then the rest are better off. But
just in case it isn’t, and not everybody read the manual

Amongst us all, we’ll get it covered!


I have the Nikon 880, and I never heard of using a gray card for
setting white balance. Maybe I just didn’t read that page in the
manual. For setting white balance I set up the shot with the lighting
positions I’m using, then go through the measuring process. I do it
at= the beginning of every session, since I’ve noticed that positions
of the lights, and ambient light, makes a difference. I find the
white balance setting feature one of the best things about digital
photography, since I can use any kind of lights.

Janet Kofoed

Hi Noel, I have the Nikon4500, next version up from 995. It offers 7
white balance settings including Auto…for the most part the Auto
feature has worked well for me.

Check out for a lot of free online info
for Nikon, Canon, Olympus, & Sony cameras, and a lot of general info
on digital photography. It offers easier to understand ‘how to’s’
than the owners’ manuals.

If you want to contact me, I would be happy to send some examples of
the quality pics this camera makes for me.


Gray cards are used to set EXPOSURE when shooting with conventional
film. It does not work for setting white balance. When you are
shooting jewelry that is too small for the built in meter in a
camera to give an accurate reading you slip the 50% gray card in and
set the exposure from that reading. This is especially helpful when
shooting against black or white backgrounds. I have used it for
years and usually set slide exposures about one stop below what it
reads. Film/slide shooters should set up there standard system of
lights etc. then shoot and record a set of exposures based on the
gray card. Bracket the suggested setting a stop or two on each side.
That should give you a solid idea what works best. From that point
on you should be able to nail the exposer every time using just the
gray card. Oh, by the way, it is a special card available from camera
supply houses. It is 50% gray card. Bill

That was an excellent answer Re: grey cards, except that grey cards
are EIGHTEEN percent grey, not 50%. (I was a graphic arts cameraman
in a previous lifetime.)

For more than you wanted to know abot them, go to:

David Barzilay, Lord of the Rings

    Gray cards are used to set EXPOSURE when shooting with
conventional film. It does not work for setting white balance. 

Hi Bill,

Just a quick question. Is it correct to say then that grey cards are
used to set the exposure where as a “white card” (if there is such a
thing as a white card) would be used to help you set the correct
color temperature of the image when you adjust it with image editing

Sorry if I am using incorrect terminology here.

Dan T.
Near Pittsburgh and wishing for a non-white christmas.

That would be an 18% gray card.

To most people, 18% gray looks like it’s ‘halfway’ between white and
black, and it’s the value that most meters are calibrated to.


I finally got one of those translucent cake-savers for a photography
dome. I carefully measured and marked out a circle to cut out for
the camera. Then I tried: A hobby knife. A steak knife. A
serrated utility knife. A keyhole saw. A pair of diagonal cutters.
What are you folks cutting this stuff with, anyway??


I used a slitting disc on my flex shaft to cut my dome, and then
used a 1/2 round file to smooth the edges, when I made mine a couple
years ago. The thicker ones can be quite tuff to cut. Ed in Kokomo

You can definitely use a shot that includes a grey card for color
correction in a program like Photoshop after the fact. You can also
use a pure white card to correct the White Balance for a particular
exposure setup if your camera has an adjustable white balance
control. The back side of the Kodak Grey card is a 90% reflectance
white and will work quite well for this. Many cameras only offer
three manual settings (Sunlight, Incandescent, Fluorescent) so you
should set it for the light you are using and then color correct in
an image editing program like Photoshop.

If you are trying to get accurate color from your shots setting
White Balance is not enough to get the correct colors in your
images. Color correction is a complex job and you need to do some
reading to get a handle on it. There is a very good book about
color correction in Photoshop that you should get if you want the
definitive book. It is titled Professional Photoshop: The Classic
Guide to Color Correction by Dan Margulis. It is not lightweight
reading but his techniques work. I have the 1998 version, I see that
there is a newer version out that covers Photoshop 7

Jim Binnion James Binnion Metal Arts Phone (360) 756-6550 Toll Free
(877) 408 7287 Fax (360) 756-2160
@James_Binnion Member of the Better Business Bureau

Where did you get the “translucent cake server”? Is that the same as
the $1 salad bowl from the dollar store others are using? I looked in
two “dollar” stores, Dollar General and the Dollar Tree, and I
couldn’t find anything like the thing in the photos at either.
Where should I look next?

Dian Deevey

  Where did you get the "translucent cake server"? Is that the
same as the $1 salad bowl from the dollar store others are using? 

I got the “cake saver” - large cover with flat platter - at a local
salvage store, Building 19. I’ve seen it other places - maybe Big
Lots, or places like that. I couldn’t find the bowls either - stock
differs with location, or there are a lot of jewelry photographers
in my neighborhood. The dome is about the color of Tupperware - not
clear, not really white. And tough -!


If you don’t want to go get a “real” grey card, a “slap-dash” one
can be made out of an average page of newspaper (mostly small print
articles, not headline pages).


...Then I tried:  A hobby knife.  A steak knife.  A serrated
utility knife.  A keyhole saw.  A pair of diagonal cutters. What
are you folks cutting this stuff with, anyway?? 

Hi Tas, I cut mine with a 2.5" hole saw. This is the kind that fits
in your electric drill and is used for such things as wood and
drywall. Mine has a regular drill bit in the center which keeps the
hole saw from traveling. I think most of them do. You can get them
at just about any hardware store where they keep the drill bits.
This made a nice clean hole for me.

Best Regards,