Custom white balance question.

OldGoat

I've been net(re)searching to learn about this but I've just become more and more confused. I understand the machanics of setting up a custom WB on my camera but what image should I use? Some sources tell me to use white card or paper or whatever white background Ihave to hand, others tell me to use an 18% grey card (and even that percentage is in dispute depending on what camers you are using).

Will shooting a page of white photocopy paper really give me the same results as using greycard? Does using that 18% grey actually make a significent difference in the white balance?

Paulw

The camera uses 18-20% grey as "white", for the white balance.

So, ideally a pure white page (A4 paper) will be too bright.

pete4130

White paper or white wall is fine. If your shooting RAW it doesn't make so much difference.

sineadw

pete4130 wrote: »

If your shooting RAW it doesn't make so much difference.

It's nice to have the reference though - especially if you have a batch of shots to adjust.

OldGoat

Paulw wrote: »

The camera uses 18-20% grey as "white", for the white balance.

So, ideally a pure white page (A4 paper) will be too bright.

This article <link> is saying that the camera light meter are set to the ANSI standard of 12% grey and that the 18% figure we throw about stems from the print world.

So now I have figures of 0% (pure white), 12% and 18-20% grey to set my white balance. See why I'm getting a bit lost.

If your shooting RAW it doesn't make so much difference

Agreed but I'm trying to get the best image I can pre-edit.

Thecageyone

pete4130 wrote: »

If your shooting RAW it doesn't make so much difference.

That's how I roll.

I adjust by eye in Lightroom. Less hassle than faffing about with paper and cards and worrying about percentages. You can always use the eye dropper on there and select a black/white/neutral grey area to adjust. I don't think there is such thing as the perfect balance. It's all relative/subjective/whathehellwouldIknowanyway ...

magicbastarder

Paulw wrote: »

The camera uses 18-20% grey as "white", for the white balance.

really? i'd have assumed that the intensity of the card would make little difference, that it's just as long as it's neutral - i.e. reflects all wavelengths equally.

Paulw

There seem to be many different views out there, and it differs from camera make to camera make. Nikon is different to Canon, is different to Sony, etc.

http://www.digitalartsphotography.com/instructions.htm

http://www.cambridgeincolour.com/tutorials/white-balance.htm

http://www.photoshop-tutorials-plus.com/grey-card.html

nilhg

OldGoat wrote: »

This article <link> is saying that the camera light meter are set to the ANSI standard of 12% grey and that the 18% figure we throw about stems from the print world.

So now I have figures of 0% (pure white), 12% and 18-20% grey to set my white balance. See why I'm getting a bit lost.


Agreed but I'm trying to get the best image I can pre-edit.

The light meter only worries about exposure not white balance.

To set a custom white balance you need a some reference point that you know is a neutral colour, that has no tint, so a piece of white paper or a grey card at 12% or 18% won't make much difference as long as it has a neutral colour.

If you take a picture of a white card with the white balance set correctly and then run the eyedropper tool over it in PS or LR then it should report exactly the same RGB values ie for a white card 255,255,255, if your exposure is correct but that could also be 200,200,200 if you've underexposed.


Shooting in RAW lets you do this in PP.

Ballyman

I use one of these to set the white balance afterwards. Put camera into RAW mode and take a shot of it before you start using the daylight WB setting and then carry on as normal (with the camera in daylight WB setting)

Then when processing you get the white balance of the xpo shot and apply it to the rest. It works perfectly.

Obviously if the light is changing all the time then it's no good but under controlled conditions it's ideal.

mumof2

Just as well im not into the technical stuff, or I'd go crazy when taking my pictures!! Taking notes of what I took in what mode etc etc was enough technical info for me yesterday!!:D

Oh, and as PaulW says, there are many different views, and this is why I prefer to buy a book!;)

OP best of luck understanding - I never will:o

OldGoat

mumof2 wrote: »

OP best of luck understanding - I never will:o

Yes you will. It sinks in slowly.
Oh, as for taking notes of your settings you should look up EXIF information. All your photographs will have EXIF information attached. Do a right click and look at the properties of the photos. It will contain stuff like aperture setting, shutter speed, ISO and so on.

SetOverSet

nilhg wrote: »

To set a custom white balance you need a some reference point that you know is a neutral colour, that has no tint, so a piece of white paper or a grey card at 12% or 18% won't make much difference as long as it has a neutral colour.

I read somewhere that the little disc inside an instant coffee jar lid does a good job... have just tried it and although the gf's looking at me strange, I have to say it does

I rarely set a custom WB myself though, just shoot RAW and find something neutral in the image later to use the eyedropper on, but definitely helpful to have a reference later on especially if you have nothing neutral in the scene to refer to; in those situations, I find you can convince yourself that any sort of way off WB is spot on, if you look at it long enough...

mumof2

OldGoat wrote: »

Yes you will. It sinks in slowly.
Oh, as for taking notes of your settings you should look up EXIF information. All your photographs will have EXIF information attached. Do a right click and look at the properties of the photos. It will contain stuff like aperture setting, shutter speed, ISO and so on.

And I just asked in another post how to get that info:D:D I love it here!! You learn so much in a day:o

mumof2

Thecageyone wrote: »

That's how I roll.

I adjust by eye in Lightroom. Less hassle than faffing about with paper and cards and worrying about percentages. You can always use the eye dropper on there and select a black/white/neutral grey area to adjust. I don't think there is such thing as the perfect balance. It's all relative/subjective/whathehellwouldIknowanyway ...

I agree with you, less hassle the better, not that Ive heard of eyedropper......however is it ok to use Auto White Balance on the camera when shooting RAW? (Manual Focusing of course). Cheers.

SetOverSet

mumof2 wrote: »

I agree with you, less hassle the better, not that Ive heard of eyedropper......however is it ok to use Auto White Balance on the camera when shooting RAW? (Manual Focusing of course). Cheers.

Yes, it's generally OK to use Auto WB and fix it later, if you shoot RAW. The only issue I can think of, and I wouldn't worry too much about it, is that AFAIK different (inaccurate) WB's will give different color (i.e. red, green or blue) histograms so if you worried about colour channels clipping and are keeping an eye on your colour histograms, you'll probably want to get your WB fairly good in camera... There's a bit on luminosity and colour histograms here if you're interested.

mumof2

SetOverSet wrote: »

Yes, it's generally OK to use Auto WB and fix it later, if you shoot RAW. The only issue I can think of, and I wouldn't worry too much about it, is that AFAIK different (inaccurate) WB's will give different color (i.e. red, green or blue) histograms so if you worried about colour channels clipping and are keeping an eye on your colour histograms, you'll probably want to get your WB fairly good in camera... There's a bit on luminosity and colour histograms here if you're interested.

Oh God, I don't even read histograms (cause I don't know how or why I should:o), but thanks for info.

FoxT

I get good results from the Custom WB on my 40D. If I'm shooting under tungsten, I just take a reference pic of a sheet of A4 paper. It doesn't even have to be in focus.

If I am shooting soccer under artificial light, before the game I will take a close-up shot of one of the goalposts & use that for custom WB. Works very well, but your mileage may vary here if the ambient light is changing during the game (ie if the match starts at or close to sunset)

For WB purposes, it doesnt matter if you use a white or gray reference.

18% grey cards used to be used a lot in the film days to set exposure, and they still can be used, but I prefer to check the histogram.

- FoxT

Thecageyone

mumof2 wrote: »

I agree with you, less hassle the better, not that Ive heard of eyedropper......however is it ok to use Auto White Balance on the camera when shooting RAW? (Manual Focusing of course). Cheers.

Of course it is! Because you can change it to whatever you like in post processing If auto looks good to you, then it's grand.

In lightroom the eyedropper tool looks exactly as it sounds. It looks like a little eye-dropper

http://farm3.static.flickr.com/2719/4045590873_ecd2378572.jpg

You click that and select a grey/black area within the image and it's supposed to correct the white balance. I almost always just do it on the temp [Kelvin] scale manually though.

kelly1

I second Nilhg! (fwiw)

Fajitas!

OldGoat wrote: »

I've been net(re)searching to learn about this but I've just become more and more confused. I understand the machanics of setting up a custom WB on my camera but what image should I use? Some sources tell me to use white card or paper or whatever white background Ihave to hand, others tell me to use an 18% grey card (and even that percentage is in dispute depending on what camers you are using).

Will shooting a page of white photocopy paper really give me the same results as using greycard? Does using that 18% grey actually make a significent difference in the white balance?

If you really want to be anal about your white balance, you'll need to work in a completely light control-able environment, stock up with lights of the same kelvins, and use their numbers to make up your CWB. But if it's for stock you're shooting, and it's colour in general you want to be 100% accurate with, you're going to need to go further than custom white balance, and use a Macbeth Colour Chart/Checker, and fix in post. If you've the same light set up, and no variables from other light, it's quite easy put together an action to match.

OldGoat wrote: »

Agreed but I'm trying to get the best image I can pre-edit.

To be honest, save yourself time and stress and do it in post w/RAW files - You'll have a better (bigger) image on your screen to work with, and you can decide a much more accurate warmth/tone than the back of your screen!

Thecageyone wrote: »

That's how I roll.

I adjust by eye in Lightroom. Less hassle than faffing about with paper and cards and worrying about percentages. You can always use the eye dropper on there and select a black/white/neutral grey area to adjust. I don't think there is such thing as the perfect balance. It's all relative/subjective/whathehellwouldIknowanyway ...

Technically, there is a 'perfect' white balance. But 9 times out of 10, you're better off doing it the way you're doing it - By eye. The problem with perfect white balances' is they're often too perfect, and in fact, not what your eyes are seeing, or what your project wants.

You click that and select a grey/black area within the image and it's supposed to correct the white balance. I almost always just do it on the temp [Kelvin] scale manually though.

I think it's to be used on a neutral/highlight rather than a midtone/black. Or at least, the closest to 18% grey/equal amounts of RGB you can find. Open to correction on that, it's not something I'd use too often.

Oh God, I don't even read histograms (cause I don't know how or why I should)

Then don't! Don't worry about them, don't worry about 'perfect' histograms, just worry about the image on the back of your camera! If it looks ok, then go with it. I think I've used the on-camera histogram twice, maybe three times in the last 8 years.

however is it ok to use Auto White Balance on the camera when shooting RAW? (Manual Focusing of course). Cheers.

Absolutely. It's ok most times when you're not shooting RAW files too. There are some times when the auto white balance won't get it right, but most times, it's just fine. It has nothing to do with manual focusing either, mind

OldGoat

Fajitas! wrote: »

If you really want to be anal about your white balance, you'll need to work in a completely light control-able environment, stock up with lights of the same kelvins, and use their numbers to make up your CWB. But if it's for stock you're shooting, and it's colour in general you want to be 100% accurate with, you're going to need to go further than custom white balance, and use a Macbeth Colour Chart/Checker, and fix in post. If you've the same light set up, and no variables from other light, it's quite easy put together an action to match.
To be honest, save yourself time and stress and do it in post w/RAW files - You'll have a better (bigger) image on your screen to work with, and you can decide a much more accurate warmth/tone than the back of your screen!

You said 'anal'. Pfnarrr!

I'm working on getting the tabletop studio nicely set up and to that end I'm using temperature matched daylight CFL's. I've thought about using the colour chart checker but I've a lot to learn first, such as WB in all its glory - hence picking the brains of Boardsies.

I know that RAW adjustments are as easy as pie but it's a learning thing for me. The ‘anal’yst in me insists that I work from first principles. (You'll be horrified to hear that I'm thinking of working with film next. I might have one or a thousand questions to plague you with on that.)

My problem is my lack of experience. First I hear of very precise measurements - the 18% grey thing. Next moment I'm hearing that shooting any old white wall (or goalpost ) is good enough. It's the disparity between precision and casualness that throws me. With time, experience and practice I'll move over to the 'casual' side but during my first faltering steps I am staying very much on the methodical side of things.

charybdis

OldGoat wrote: »

You said 'anal'. Pfnarrr!

I'm working on getting the tabletop studio nicely set up and to that end I'm using temperature matched daylight CFL's. I've thought about using the colour chart checker but I've a lot to learn first, such as WB in all its glory - hence picking the brains of Boardsies.

I know that RAW adjustments are as easy as pie but it's a learning thing for me. The ‘anal’yst in me insists that I work from first principles. (You'll be horrified to hear that I'm thinking of working with film next. I might have one or a thousand questions to plague you with on that.)

My problem is my lack of experience. First I hear of very precise measurements - the 18% grey thing. Next moment I'm hearing that shooting any old white wall (or goalpost ) is good enough. It's the disparity between precision and casualness that throws me. With time, experience and practice I'll move over to the 'casual' side but during my first faltering steps I am staying very much on the methodical side of things.

The reality is that accurate colour out of the camera isn't really a realistic goal. Every step of your colour pipeline (raw converter or in-camera JPEG engine, colourspace, system colour, monitor calibration, printer calibration) introduces new possibilities for divergence and multiple different possibilities all of which may be technically correct.

Also, those temperature-matched CFLs you have? They're probably not as matched or accurate as you'd think. That 18% grey card? Probably not 18% grey.

By all means, try to get it right in-camera, but understand where doing so becomes futile due to the diminishing returns of time you spend getting it right compared to the time you'll save yourself in post. If you really are concerned about accurate colour, you're going to end up grading/correcting anyway.

FoxT

There is an interesting read here:

http://cool.conservation-us.org/waac/wn/wn21/wn21-3/wn21-308.html

My approach is to WB (& everything else) try & get it as good as I can out of the camera. To do this I find something white, take a shot & custom WB it.

Shooting RAW is not always possible, (ie sports) so using custom WB in the camera can help a lot here. Occasionally the jpgs may need a little tweak here & there, but not much. The goalpost idea may sound imprecise - but, it actually works quite well!

@Paul, you state "The camera uses 18-20% grey as "white", for the white balance.

So, ideally a pure white page (A4 paper) will be too bright."


This is not my understanding at all - in fact, I believe that you can use white or gray to set white balance, provided you don't over- or under- expose. Am I incorrect in this?


And finally.... there are some situations where white balance will be difficult, if not impossible: For example, with sodium vapour streetlights
( the orange ones), there is virtually no blue available - best solution in many cases like this is just do a B&W conversion!

mrboswell

Thecageyone wrote: »

That's how I roll.

I adjust by eye in Lightroom. Less hassle than faffing about with paper and cards and worrying about percentages. You can always use the eye dropper on there and select a black/white/neutral grey area to adjust. I don't think there is such thing as the perfect balance. It's all relative/subjective/whathehellwouldIknowanyway ...

If you have the same conditions e.g. studio lights it would be much easier to set before hand and save yourself extra work later. But you are right that it is easy to adjust it in Lightroom.

I don't always use lightroom though as I'm sometimes too lazy to import the photos!

Thecageyone

I se it 100% of the time so I tend not to worry too much on WB when shooting. I probably should try to get it spot on, but I usually slap it into Auto knowing I can correct later.

On the eyedropper; here's a tutorial for using it in PS:

http://www.eyefetch.com/tutorial-white-balance-ps.aspx

This method involves using 3 step-correction; White, black and neutral. All of them will work.