Are some colour balance settings better than others?

On 11/15/2010 11:53 AM, John McWilliams wrote:
On 11/15/10 PDT 2:18 AM, Superzooms Still Win wrote:


You're all nothing but useless jokes to the photography world.

But we're grateful you're still hangin' with us to the bitter end.

was that posting really from YOU! or an impostor. ;-)

--
Peter

Gary Eickmeier wrote:

Custom white balance off a gray card should make all colors accurate.

A "grey card" isn't necessarily grey. All it has to do is reflect 18% of the
incident light, but unless the manufacturer says it does, don't assume that
it will do so equally across the spectrum of colours. Still, an ordinary
grey card will give you some data to work with.

On 11/15/2010 12:37 PM, George Kerby wrote:



On 11/15/10 9:31 AM, in article
, "Dudley Hanks"
wrote:

wrote:
Dudley Hanks wrote:
Paul Furman wrote:
Dudley Hanks wrote:

When it comes to getting an accurate read on the white in a
picture, how much of the frame needs to be white? The whole
frame? Half? Less?

You need to fill the full frame for setting custom WB in-camera but for
post-processing, you can use any tiny bit of white or neutral gray. It
doesn't have to be exact to help a lot. If there are two colors coming
from each side, the positioning of the gray card is difficult and things
can get messy so try to tilt it to an angle that get's a representative
amount of light from each side. That's usually not a big problem.

I would think any sort of reasonable gray piece of whatever, about
letter sized would work (it doesn't matter if it's in focus, just fill
the screen under the ambient light, and I'm embarrassed that I haven't
bothered with this myself. I do set custom WB in a studio table top
setting when doing macro though. For field work I often wish I'd shot a
gray card when trying to eyedropper around for a neutral spot...

So, my old 18% grey card should work? As long as I fill the
frame...

It's unlikely to be spectrally neutral, like a WhiBal card
(http://www.rawworkflow.com/whibal/).

I haven't had much luck finding white balance cards locally,
guess I may have to go on-line to get one.

How about using a white reflector? I've got this nice 4-
footer that's pretty pure. Wouldn't be too difficult to fill
the full frame using it ...

Or, would it be too reflective?

Take care,
Dudley

Dudley, there are a lot of sellers for the Kodak Gray Card online.

It is 18% neutral gray on one side and 90% neutral white on the other, so it
can be used for white balance and reflective meter readings.

B&H has a two pack for 29.95 US and Amazon has a single off-brand for less
than 15.00 US

Google "Kodak 18% gray card" and you'll get a lot of hits.

Good luck!


I have been reading that 18% gray is fine for exposure, but not really
the best for digital color balance.

http://www.rmimaging.com/information/dgc_faq.html



--
Peter

On 11/15/10 5:08 PM, peter wrote:
On 11/15/2010 11:53 AM, John McWilliams wrote:
On 11/15/10 PDT 2:18 AM, Superzooms Still Win wrote:


You're all nothing but useless jokes to the photography world.

But we're grateful you're still hangin' with us to the bitter end.

was that posting really from YOU! or an impostor. ;-)


Yes, some impostor! I imagine that when my brain sits in a jar on
someone's desk, the madness will have stopped......

--

JPM

I know that you believe you understood what you think I said, but I'm
not sure you realize that what you heard is not what I meant.

On 11/15/10 7:11 PM, in article
m, "Wilba"
wrote:

Gary Eickmeier wrote:

Custom white balance off a gray card should make all colors accurate.

A "grey card" isn't necessarily grey. All it has to do is reflect 18% of the
incident light, but unless the manufacturer says it does, don't assume that
it will do so equally across the spectrum of colours. Still, an ordinary
grey card will give you some data to work with.

How's Fred doin', Wilma?

George Kerby wrote:
Wilba wrote:
Gary Eickmeier wrote:

Custom white balance off a gray card should make all colors accurate.

A "grey card" isn't necessarily grey. All it has to do is reflect 18% of
the
incident light, but unless the manufacturer says it does, don't assume
that
it will do so equally across the spectrum of colours. Still, an ordinary
grey card will give you some data to work with.

How's Fred doin', Wilma?

I have no knowledge of his sex life.

On Tue, 16 Nov 2010 09:11:43 +0800, "Wilba"
wrote:

Gary Eickmeier wrote:

Custom white balance off a gray card should make all colors accurate.

A "grey card" isn't necessarily grey. All it has to do is reflect 18% of the
incident light, but unless the manufacturer says it does, don't assume that
it will do so equally across the spectrum of colours. Still, an ordinary
grey card will give you some data to work with.

I have an interesting light-source test card from Kodak, called their
"Kodak Color Viewing Light Selector" (on back: published 1991-03, P3-180,
ref: Kodak pub. E-84) with 2 abutted panels of magenta pigments on it.
Designed to determine if a source-light, for most intents and purposes, has
all the available spectrum of a true 5000K light source. In daylight both
panels of magenta will be indistinguishable. In artificial lights, only if
the artificial light provides full daylight spectrum will the two shades of
magenta appear the same. I find this a much more helpful photographer's
tool, especially for digital cameras, than any 18% gray card. It is
especially handy when wanting to quickly determine if some "full spectrum"
fluorescent lights are closely emulating daylight, then it is best to use
the daylight white-balance option on a digital camera than any fluorescent
white balance option. It is also extremely invaluable for proofing prints,
knowing if the light you are proofing them under will be applicable to
generic viewing conditions.

Good luck finding one!

:-)

peter wrote:
Google "Kodak 18% gray card" and you'll get a lot of hits.

Good luck!


I have been reading that 18% gray is fine for exposure, but not really
the best for digital color balance.

http://www.rmimaging.com/information/dgc_faq.html

Marketing hype, much of which is technically invalid.

Kodak has always advertized their Gray card as suitable for
exposure and color calibration. It has been the industry
standard for decades (and was nearly the only thing available
for most it's history).

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

On Mon, 15 Nov 2010 19:27:50 -0900, (Floyd L. Davidson)
wrote:

peter wrote:
Google "Kodak 18% gray card" and you'll get a lot of hits.

Good luck!


I have been reading that 18% gray is fine for exposure, but not really
the best for digital color balance.

http://www.rmimaging.com/information/dgc_faq.html

Marketing hype, much of which is technically invalid.

Kodak has always advertized their Gray card as suitable for
exposure and color calibration. It has been the industry
standard for decades (and was nearly the only thing available
for most it's history).

That's what you get for believing marketing hype.

Dudley Hanks wrote:


The idea is to produce an artificially high degree of contrast
in the scene, in order to facilitate low-vision image
composition.

Have you considered using a laptop or netbook, with a camera
in tethered mode?

You could then use the much larger display of the computer,
and whatever image enhancement software you can find (or write)
for composition.

BugBear