White Balance & Gray Card

gypsy3001.TakeThisOut@yahoo.com wrote:
> Dave Lotek wrote:
> > What's the difference between using a gray card with film and using
> > white balance with digital? Why not use a gray card with digital?
> > Forgive me if I sound stupid but it's still a mystery to me. Thanks
> > for your reply.
>
> You can still use a gray card with a digital camera . . . for metering.
>
> I don't understand how you would white balance with a gray card. You
> have to white balance with a white card . . . or a white sheet of
> paper. Or is there a recent change in technology that I am not aware
> of?

Well, what you need is something that reflects all wavelengths equally
(roughly). There is no difference, in this context, between a white
card and a gray one. For example, spot meter off a white card and
expose as the camera suggests. You'll get gray. The point here is that
the perceived colour of an object doesn't change if the reflectivity
for all wavelengths is changed by the same factor.
 >> Stay informed about: White Balance & Gray Card 

<gypsy3001 DeleteThis @yahoo.com> wrote in message
news:1155775865.570601.57320@i3g2000cwc.googlegroups.com...
>
> Dave Lotek wrote:
>> What's the difference between using a gray card with film and using
>> white balance with digital? Why not use a gray card with digital?
>> Forgive me if I sound stupid but it's still a mystery to me. Thanks
>> for your reply.
>
> You can still use a gray card with a digital camera . . . for metering.
>
> I don't understand how you would white balance with a gray card. You
> have to white balance with a white card . . . or a white sheet of
> paper. Or is there a recent change in technology that I am not aware
> of?
>
> Chieh

You can white balance with a black card if you want ...

Like another poster mentions, you want an absence of color.

Jay
 >> Stay informed about: White Balance & Gray Card 

Jay Beckman wrote:
> You can white balance with a black card if you want ...
>

Of course, if it really is black, it'll take you an infinite amount of
time...


> Like another poster mentions, you want an absence of color.
>
> Jay
 >> Stay informed about: White Balance & Gray Card 

acl wrote:
> gypsy3001.RemoveThis@yahoo.com wrote:
>> Dave Lotek wrote:
>>> What's the difference between using a gray card with film and using
>>> white balance with digital? Why not use a gray card with digital?
>>> Forgive me if I sound stupid but it's still a mystery to me. Thanks
>>> for your reply.
>> You can still use a gray card with a digital camera . . . for metering.
>>
>> I don't understand how you would white balance with a gray card. You
>> have to white balance with a white card . . . or a white sheet of
>> paper. Or is there a recent change in technology that I am not aware
>> of?
>
> Well, what you need is something that reflects all wavelengths equally
> (roughly). There is no difference, in this context, between a white
> card and a gray one. For example, spot meter off a white card and
> expose as the camera suggests. You'll get gray. The point here is that
> the perceived colour of an object doesn't change if the reflectivity
> for all wavelengths is changed by the same factor.

Hi...

One more way of saying much the same thing, but may
make it a little more understandable...

In the white balance context - white doesn't mean white,
but rather refers to an absence of color.

Take care.

Ken
 >> Stay informed about: White Balance & Gray Card 

On Thu, 17 Aug 2006 00:02:29 +0000 (UTC), Dave Lotek
<Dave_Lotek DeleteThis @yahoo.com> wrote:

>What's the difference between using a gray card with film and using
>white balance with digital? Why not use a gray card with digital?
>Forgive me if I sound stupid but it's still a mystery to me. Thanks
>for your reply.
>
>Dave


I think you're confusing the purpose of the gray card, which is used
to help set exposure, with white balance.
--
Bill Funk
replace "g" with "a"
 >> Stay informed about: White Balance & Gray Card 

Bill Funk wrote:
> On Thu, 17 Aug 2006 00:02:29 +0000 (UTC), Dave Lotek
> <Dave_Lotek.TakeThisOut@yahoo.com> wrote:
>
>>What's the difference between using a gray card with film and using
>>white balance with digital? Why not use a gray card with digital?
>>Forgive me if I sound stupid but it's still a mystery to me. Thanks
>>for your reply.
>>
>>Dave
>
>
> I think you're confusing the purpose of the gray card, which is used
> to help set exposure, with white balance.

So, do you disagree with the following statement: "One can set white
balance by using a gray card"?
 >> Stay informed about: White Balance & Gray Card 

On Thu, 17 Aug 2006 17:45:15 +0200, acl
<achilleaslazarides.DeleteThis@yahoo.co.uk> wrote:

>Bill Funk wrote:
>> On Thu, 17 Aug 2006 00:02:29 +0000 (UTC), Dave Lotek
>> <Dave_Lotek.DeleteThis@yahoo.com> wrote:
>>
>>>What's the difference between using a gray card with film and using
>>>white balance with digital? Why not use a gray card with digital?
>>>Forgive me if I sound stupid but it's still a mystery to me. Thanks
>>>for your reply.
>>>
>>>Dave
>>
>>
>> I think you're confusing the purpose of the gray card, which is used
>> to help set exposure, with white balance.
>
>So, do you disagree with the following statement: "One can set white
>balance by using a gray card"?

Are you looking for trouble?
Did I say that?
If you want to set white balance with a gray card, fire away.
--
Bill Funk
replace "g" with "a"
 >> Stay informed about: White Balance & Gray Card 

"acl" <achilleaslazarides.RemoveThis@yahoo.co.uk> wrote in message
news:1155829326.525214@seven.kulnet.kuleuven.ac.be...
> Bill Funk wrote:
> > On Thu, 17 Aug 2006 00:02:29 +0000 (UTC), Dave Lotek
> > <Dave_Lotek.RemoveThis@yahoo.com> wrote:
> >
> >>What's the difference between using a gray card with film and using
> >>white balance with digital? Why not use a gray card with digital?
> >>Forgive me if I sound stupid but it's still a mystery to me. Thanks
> >>for your reply.
> >>
> >>Dave
> >
> >
> > I think you're confusing the purpose of the gray card, which is used
> > to help set exposure, with white balance.
>
> So, do you disagree with the following statement: "One can set white
> balance by using a gray card"?

That statement is actually true for some cameras, because I do have an older
point-and-shoot digital camera that uses gray to set manual white balance.

From the Nikon Coolpix 2100 manual, page 61:

[begin quoted text]
Preset white balance is used when shooting under mixed lighting or to
compensate for light sources with a strong color cast (for example, to make
pictures taken under a lamp with a red shade look as through they had been
taken under white light).

....

To measure a new value for white balance, place a gray object, such as a
piece of cardboard, under the lighting that will be used in the final
picture. Frame this object so that it fills the square in the center of the
menu shown above. Highlight Measure and press the multi selector to the
right to measure a new value for white balance (shutter will be released and
camera will return to original zoom position, but no picture will be
recorded).
[end quoted text]
 >> Stay informed about: White Balance & Gray Card 

acl wrote:
> Bill Funk wrote:
>> On Thu, 17 Aug 2006 00:02:29 +0000 (UTC), Dave Lotek
>> <Dave_Lotek DeleteThis @yahoo.com> wrote:
>>
>>> What's the difference between using a gray card with film and using
>>> white balance with digital? Why not use a gray card with digital?
>>> Forgive me if I sound stupid but it's still a mystery to me. Thanks
>>> for your reply.
>>>
>>> Dave
>>
>>
>> I think you're confusing the purpose of the gray card, which is used
>> to help set exposure, with white balance.
>
> So, do you disagree with the following statement: "One can set white
> balance by using a gray card"?

Hi...

Oddly worded, so just in case...

One CAN set white balance using a gray card.

If anyone is skeptical, google gray card, note the
number of responses that come up referring to the use
we're speaking about.

Try it again with white card, see what you find, again
paying attention to the context.

Take care.

Ken
 >> Stay informed about: White Balance & Gray Card 

Ken Weitzel wrote:

>Oddly worded, so just in case...
>
>One CAN set white balance using a gray card.
>
>If anyone is skeptical, google gray card, note the
>number of responses that come up referring to the use
>we're speaking about.
>
>Try it again with white card, see what you find, again
>paying attention to the context.

Here's an article on the subject:
http://www.outbackphoto.com/workflow/wf_65/essay.html

Short answer is that you can use a gray card for white balance because
your camera can't tell the difference between a white card in low
light and a gray card in bright light. As long as your gray card
really is a true *neutral* gray (and some cheap ones aren't) you'll be
OK.

Personally I use white mat board scraps. You'll find that art stores
have a huge number of different shades of "white". Experiment and
you'll be able to come up with "white cards" that produce all kinds of
variations from warm to cool. Just be sure to keep notes - including
the manufacturer and catalog number of mat board samples that produce
color balances you like.

--
Mark Roberts Photography & Multimedia
www.robertstech.com
412-687-2835
 >> Stay informed about: White Balance & Gray Card 

Dave Lotek wrote:

> What's the difference between using a gray card with film and using
> white balance with digital? Why not use a gray card with digital?
> Forgive me if I sound stupid but it's still a mystery to me. Thanks
> for your reply.
>
> Dave

Why not indeed? I do it.

White balance in digital is like chosing the right film i.e. daylight
film or tungsten or putting a magenta correcting filter on the lens when
you're shooting under flourescent lights.

Grey card is useful in setting exposure, i.e. getting neutral midtone.
They're not mutually exclusive.

I usually carry a Macbeth color checker and a triple card that has
white/gray/black. Shoot the first frame with the color checker and
triple card & you can batch process your color correction for the rest
of anything you shoot under the same light.
 >> Stay informed about: White Balance & Gray Card 

Ken Weitzel wrote:

>
> In the white balance context - white doesn't mean white,
> but rather refers to an absence of color.

In the white balance context - white means the color temperature of
white under specific types of light: 3200k for tungsten, 5400k for
daylight, 6000k for flash, 10,000k for skylight ...
 >> Stay informed about: White Balance & Gray Card 

acl wrote:

> "One can set white
> balance by using a gray card"?

i AGREE with that statement....one CAN set wb with a grey card. a
photographer's grey card is purposely neutral in color.

and i will go even further,,,,A GREY CARD IS BETTER THAN A WHITE CARD
FOR WB, because white will reflect more ambient color than grey.
 >> Stay informed about: White Balance & Gray Card