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View Full Version : Setting Grey Point - Am I going crazy?



hoffy
20-09-2009, 5:47pm
OK, heres the situation.

I took some photos of the girls today. I have some new goodies, so I wanted to try them out. Since I bought a standard run of the mill Grey card, I thought I'd give that a shot to see how improved my shots would be.....I had my youngest hold the card at the beginning and end, took a shot and then continued on.

In post processing, I took the shot, opened it in Adobe RAW, used the White balance tool and set the white balance by clicking on the grey card. Here is a before and after:

Before
http://www.ashhoffimages.com.au/ashoim_gallery/albums/non_gallery/Grey_Test_defaultDSC04140.jpg

After
http://www.ashhoffimages.com.au/ashoim_gallery/albums/non_gallery/Grey_test_adjustDSC04140.jpg

Now, is it my imagination, but does the after shot look way too warm? According to RAW, as shot was 55K (which it was) and it set the WB to 64K

Am I missing something?

kiwi
20-09-2009, 6:02pm
couple of things, the 2nd does look more natural to me

But, it doesnt look like a 18% grey card to me, too dark

ricktas
20-09-2009, 6:05pm
I agree with Darren, the second does look more natural to me as well. How long since you calibrated your screen Hoffy? Screens can 'shift' over time.

phild
20-09-2009, 6:08pm
The second looks good to me as well, the first looks a touch cold.

kiwi
20-09-2009, 6:08pm
by the way, not so much cool #1 but a definate magenta cast

hoffy
20-09-2009, 6:46pm
Cheers. When I look again, yes, I would say the second is closer. Just maybe a tad warm.

Yes, I need to calibrate again. It has been too long.

The card is supposedly an 18% grey. It was a "Zone System" card that I bought from the local camera store.

hoffy
20-09-2009, 6:51pm
OK, here we go again, this time I met the WB halfway And for reference, the 2nd from the OP:

http://www.ashhoffimages.com.au/ashoim_gallery/albums/non_gallery/2Grey_test_adjustDSC04140.jpghttp://www.ashhoffimages.com.au/ashoim_gallery/albums/non_gallery/Grey_test_adjustDSC04140.jpg

ricktas
20-09-2009, 7:03pm
The right side one here looks the most natural to me.

trigger
20-09-2009, 9:14pm
Hoffy. Are you sure thats 18% grey card? looks alot darker.
The 2nd image is close but still looks like its got a bit of green tint.

The 1st image has alot of magenta!

Analog6
21-09-2009, 4:13am
I agree #2 looks best, but you need to stand the child beside your monitor and compare them that way. Only you can say which is right.

leanneqld
21-09-2009, 12:31pm
I thought the grey card was used to get optimal exposure more so than white balance-neutral white card is better for white balance ???

Kym
21-09-2009, 12:41pm
I thought the grey card was used to get optimal exposure more so than white balance-neutral white card is better for white balance ???

The theory is an 18% (or 12%) grey is what DSLR camera software tries to average the image to.
So by giving PP a reference point it can align to the sensor.

The card looks dark to me as well. (Calibrated here)

Ash .. If you want to borrow my Huey Pro let me know.

kiwi
21-09-2009, 12:48pm
I think the card Ashley's using would be fine to set WB, to do so you only need a neutral reference point. Problem with white is that it's rarely white.

18% etc is more useful for exposure though

arthurking83
21-09-2009, 1:17pm
I'd say using matrix metering has compensated(on the dark side) and may be making the grey card look darker than it may be.

I've found using grey to balance Wb better is very effective even if the grey isn't 18%. I sometimes just use a random part of a scene that I remember to be 'grey' or grey enough. The idea is ore to neutralise the color cast rather than get correct exposure. I generally do that when lighting is mixed, or if I see an obvious colour cast(say as you would in a purple room)... or using a CPL in slightly overcast conditions(where it may produce an obvious yellow cast.

With the grey card.. the best thing to do, is to manually create a preset WB setting using the 'Pre set WB feature of your camera. the camera will confirm all the variables for you and then you shoot in that pre set WB mode. Handy for weird lighting conditions, as in this shot with the purple looking room.. which usually throws AWB off(hence the magenta cast).

Also any brand new piece of clean white paper such as an A4 sheet of printer paper can be used for pre setting WB in camera(which I've also done).

Either or both of the second images look perfectly fine. The first in both posts have a magenta cast.

DavidB
21-09-2009, 1:24pm
Firstly I'll say that the "corrected" image looks better to me than the original magenta one. But whether it's "correct" is a different question.

Leanne's on the money here: the grey card you bought (which is designed to be a particular tone/lightness) is probably not neutral (without colour). Products like the WhiBal, Lastolite white balance target, ExpoDisc, etc are meant to be neutral and used for custom white balance. Whether they come out black, grey, or white is just dependent on your exposure!

Traditional 18% "grey cards" are usually printed cardboard, and they're renowned for fading and changing colour over time. Of course it was always in Kodak's interests to sell you a fresh one every couple of years. ;) Something like a sheet of paper or a white T-shirt can be used for an approximate custom WB, but they won't be "correct" (especially in sunlight, those examples tend to flouresce slightly blue). But they can get you close, and you can tweak the sliders "by hand" a bit from there.

In the end that's often all you have: if you shoot a sunset and choose a WB to neutralise a grey/white reference, the colours may be "correct", but they won't look "right". In the end we adjust the images to "look right". Obviously this is only possible with a properly calibrated/profiled display though.

etherial
21-09-2009, 8:18pm
Also any brand new piece of clean white paper such as an A4 sheet of printer paper can be used for pre setting WB in camera(which I've also done).


I'm guessing this would be dramatically affected by the light you doe this in? ie incandesant vs fluro vs sunlight. What would be best?

kiwi
21-09-2009, 8:30pm
No. The point is to advise the camera to set a wb that makes the object being photographed look neutral/white.

etherial
21-09-2009, 8:48pm
Ahh of course, tailor the camera WB to match the light...of course.

Analog6
22-09-2009, 5:37am
Here is a 20 grey scale example - if you cannot see 20 distinctions then your monitor is off.

arthurking83
22-09-2009, 9:33am
The other problem with 'setting WB' is that you;re trying to make white look white again to offset the colour cast for the situation. Great if perfect colour accuracy is the goal, but not always desirable.

ie. if you look at a piece of white printer paper in incandescent lighting, it'll have a slight yellow cast.. that's. Setting or pre-setting Wb to make that white paper look white again may look 'correct' .. but it's not natural.

eg. at sunset/sunrise the light is a warm orange glow... taking a grey card reference, or pre setting WB usually makes the scene look much colder(colour temp), and the reason you're out there shooting at that time of the day, is then lost.

BLWNHR
22-09-2009, 6:56pm
I prefer the second shot in the OP. I think the first is far too cold.

Colourised
24-09-2009, 1:47am
the 2nd one definitely looks better.. esp with the skin tones

bigdazzler
05-10-2009, 7:18am
2 and 4 both look pretty close to me mate ..