Setting White Balance

[DerrickC]

Hi,

I bought a grey card and using the RD1 if i am shooting RAW and want to get an accurate white balance which side do i shoot? The grey side or the white side? Must the card be placed at any specific angle?

Then when i get to the PhotoRaw software to convert the RAW files i go to custom white balance and click the grey point dropper on the grey card in the image? I'm quite confused.

Appreciate any help. Thanks!

Derrick

 

[Finder]

The white side - that is why is it called white balance. Since it is just calibrating color it does not need to be in focus, but fill the frame with the white area. Just make sure the ambient light is illuminating the surface.

BTW, you can use the gray side if the strength of the illumination causes a white balance error.

 

[Finder]

The RAW dropper is a different thing. There the software is determining white balance from the selected area. There again, use the white side of the card in the image.

 

[DerrickC]

The RAW dropper is a different thing. There the software is determining white balance from the selected area. There again, use the white side of the card in the image.

So the "Grey Point" dropper in the Epson PhotoRaw software when setting custom white balance for the Raw file conversions should actually be a "white point" dropper?

So step by step, say i'm shooting an event in a fixed lighting situation:-
1) take a shot of the white side of the card.
2) shoot the event
3) When processing the Raw files, first open the image of the shot of the white side of the card, select custom white balance, and use the grey point dropper to click on the white card which would set the custom white balance
4) Apply this custom white balance to the rest of the photos when converting

Anything else i should take note of? Thanks.

 

[jaapv]

Hi,

I bought a grey card and using the RD1 if i am shooting RAW and want to get an accurate white balance which side do i shoot? The grey side or the white side? Must the card be placed at any specific angle?

Then when i get to the PhotoRaw software to convert the RAW files i go to custom white balance and click the grey point dropper on the grey card in the image? I'm quite confused.

Appreciate any help. Thanks!

Derrick

If you are having colour balance problems it might be a good idea to calibrate your monitor using a calibrating tool like colour-spider. Even without problems it is a good idea to do so, as there are plenty of shots where you want to judge colour by eye instead of relying on a non-existing neutral area. Colour balance is a bit like exposure, there is no absolute "correct"setting, it must be adapted to the subject. The grey, black or white point dropper in any software is just where the intensity values of all three colour channels are set to identical. Grey will set a mid-tone in all channels, white all channels to 255 and black all channels to 0 or 10 in the spot clicked. I don't know if you can set the size of the eye-dropper tool inPhotoraw (I tend to use Photoshop), but it should not be 1x1 pixel, but more like 5x5 or 10x10. That way you avoid clicking on one aberrant pixel and getting the balance all wrong as a result.

 

[JonasYip]

Well, you could shoot *both* sides of the card and then use whichever one works best. Though as someone else pointed out a properly calibrated monitor is important since part of color-balance is what is pleasing to you. Personally, I rarely use the "proper" white-balance as I prefer everything towards the warm side.

j

 

[furcafe]

I haven't used the dropper functions in PhotoRaw, but if it's anything like Photoshop, you'd use the black dropper on a black area, gray dropper on a gray area (which could be the gray side of your gray card), white dropper on a white area (the white side of your gray card). When using a gray card for metering, you want to angle it so that the light on the card is the same intensity as the light on your subject; I presume the same would go for setting color balance.

Hi,

I bought a grey card and using the RD1 if i am shooting RAW and want to get an accurate white balance which side do i shoot? The grey side or the white side? Must the card be placed at any specific angle?

Then when i get to the PhotoRaw software to convert the RAW files i go to custom white balance and click the grey point dropper on the grey card in the image? I'm quite confused.

Appreciate any help. Thanks!

Derrick

 

[tetrisattack]

I don't use an R-D1, but I have worked with color materials in the studio and printed in a color darkroom. We used gray cards as reference for exposure, color balance, and as a physical reference for adjusting color later.

I think the term "white balance" refers to the color of your lighting, not the color of "white" objects in the scene.

While most gray cards guarantee that their gray side is perfectly neutral in terms of both value and hue, they often make little claim about the quality of the reverse side. So unless the white side is guaranteed to be white (and how white are we talking, here? 100% reflectance?) you should use the gray side.

The best calibration target, of course, would be a full set of grayscale patches, because of exposure-related color shifts. That's mostly a film issue but I've seen digital cameras with off-color highlights and shadows due to extra sensitivity to UV and IR.

 

[pfogle]

my 2c - I think that 'white balance' is nominally correct (ie in theory, but might not suit personal taste) when a 'neutral grey' surface is translated into an RGB image with the levels equal in all channels.

Since processing of pixels from RAW into jpg etc is unreliable if any of the channels is saturated, I would think it best to use a grey rather than white surface. The problem of noise would also rule out a black, unless there was no other option.

ps I sometimes have to copy artworks; for these I use the old Kodak 18% grey card for reference.

 

[DerrickC]

thanks for all the replies. will play around with the grey/white card and see what works best for me. 🙂

 

[Finder]

The white side of the card is 90% reflective. White is used rather than gray because there is more light to work with. In low light, the gray side can be a handicap.