Total newb question about white balance...

[mkazebee]

Okay, I have the hardest time understanding dealing white balance. I know I should know it and understand it but I read up on it and my mind goes blank. Is there some easy way to understand it? I had a picture that I had taken and loved, was proud of but someone stated that my white balance was off.

So...sorry for a question on something that seems so simple...

[Colin Southern]

Hi Marie,

If you hold up a piece of white paper - and then shine a red light on it - would you agree that the "white" paper would then appear to be red? (even though it's "really white").

In a nutshell, the colour of the light that illuminates the things we photograph influences the colour of those things -- and a lot of the time that's a bad thing. And to make matters worse - the lights that we use all have different "colours" (eg if you put a fluorescent light next to an incandescent light you'd see that they were different colours -- and thus put out different coloured light - which in turn influences the colour of the objects that we're viewing). Making sense so far?

All white balancing does is apply a correction to our images to counter-act the effect of the colour of the light. If you shone a red light on your white paper you get red paper - but if we were to white balance a photo of that red paper, the software would add cyan to cancel out the red, making the white paper white again. Easy huh?

Sometimes we want to white balance a shot, sometimes we don't. Generally - for photos of people we DO want a correctly white balanced shot -- but for things like sunsets, generally we don't (because we WANT to see the colourful effects of the sunset). Another example might be if I were to photograph you and your husband enjoying a romantic candle lit dinner; in that scenario you'd EXPECT to have yellowish lighting -- in fact, if I were to correctly white balance the shot so that it looks like the two of you were illuminated with a pure white light, the shot would look fake.

There are a number of approaches to white balancing -- the easiest (in my opinion) is to take a reference shot first, with a spectrally neutral (ie pure gray) card in the shot. A gray card should reflect equal amounts of red, green, and blue - so if your post-processing software sees that the amounts of red, green, and blue are NOT equal on the card then it can only be due to the colour of the light -- and so it will white balance the shot be adjusting the ENTIRE IMAGE so that the grey card is in fact pure grey -- and then you can use the same settings (known as the colour temperature) to correct all other shots taken under the same lighting conditions.

Hope this helps

[William W]

I had a picture that I had taken and loved, was proud of but someone stated that my white balance was off.

The comment could have been ‘sort of’ correct, but it is more likely that the comment was not accurate.
It is more likely that (if the comment had any credence), that the image had a Colour Cast.
This is not meant to split hairs, just for the sake of being pedantic, but rather to show that there are many steps from exposure to the final product – for example:

It is possible that the Image gained a colour cast during Post Production
It is possible that if the Image were a print, then the lab printed it ‘with corrections’
It is possible that if the Image were being viewed on a monitor, that Monitor was NOT calibrated and the viewing room was not lit correctly for viewing.
It is also possible that the viewer was slightly colour blind – though a slim chance – I have come into discussions of this nature with Clients, who have been colour blind: and that is interesting.

So my point being that if you wish to attain ‘correct’ white balance in the ‘best practice manner’ you firstly have to ensure the LIGHTING is at SAME Colour Temperature to your Camera’s Film or DSLR’s Colour Temperature Setting.
And then (as already mentioned by Colin), you shoot a REFERENCE shot (with a Grey Card) in the first frame of every lighting set, so you can ensure each step of Processing maintains the correct White Balance.

There are several reasons why I also use this method, IF I want correct White Balance (note the use of "IF"): and that is not to say that other methods are not useful.

I mention this, because there are many who choose to shoot the image in AWB (Auto White Balance) and use 'raw' capture and then adjust the image(s) in Post Production.

This method has its merits, but also has some shortcomings, depending upon the particular shooting scenario.

Also it is important to understand that for most PRACTICAL purposes precisely ‘correct white balance’ is not really all that useful.

For example, in Portraiture, we can make an image with ‘correct white balance’ but we might choose for some artistic purpose to make that image either warmer or cooler, to convey a different feel or emotion, to the Portrait.

As an example:



WW

[Colin Southern]

So my point being that if you wish to attain ‘correct’ white balance in the ‘best practice manner’ you firstly have to ensure the LIGHTING is at SAME Colour Temperature to your Camera’s Film or DSLR’s Colour Temperature Setting.
And then (as already mentioned by Colin), you shoot a REFERENCE shot (with a Grey Card) in the first frame of every lighting set, so you can ensure each step of Processing maintains the correct White Balance.

Although it's possibly worth mentioning Bill that if they're shooting RAW then it doesn't really matter what the camera's white balance is set to (as the camera's white balance is only applied to the in-camera JPEG, not the RAW file) (although of course, it is offered to the RAW converter to use as a starting point).

[William W]

Thanks Colin.

Yes. I concur.

Thanks for pointing that out: that is a big advantage of shooting raw

Please note I did have in mind the “starting point” for raw conversion, when I wrote that.

Having a 'correct' starting point is nice.

***

But there is more . . .

ASIDE and ADDITIONAL Technical Information for those interested -

I was also being very careful with my wording here:

“So my point being that if you wish to attain ‘correct’ white balance in the ‘best practice manner’ you firstly have to ensure the LIGHTING is at SAME Colour Temperature to your Camera’s Film or DSLR’s Colour Temperature Setting.”

I was careful so my comments allowed for ALL shooting (lighting) scenarios, including the unusual shooting scenarios, which would be outside what would be generally discussed in an answer to “a ‘newbie’ question on white balance”.

As you are aware, I tend to be very careful with word choice, especially about technical topics – (too much Proof Reading, I think).

Specifically two of the more common examples (of these uncommon shooting / lighting scenarios) are:

> shooting under lights which do not have a continuous spectrum or have a very large or odd spike (Hg Lamps as one example)

> shooting under (incandescent) lights whose Colour Temperature is lower than the limit of Manual White Balance selection available (most DSLRs bottom out at about 2500°K)

In both these cases, if one really does want best image quality and best white balance with fewest problems getting that image quality and white balance: it is better to select the Manual White Balance which is closest to the Colour Temperature of the Lights and to ALSO use a CC Filter, irrespective if one is shooting raw or not.

So that's the other reason why I worded the comment, as I did.

And that's why I did NOT just write: "shoot raw and correct the WB in post and everything will always be OK", But I covered that point here:

"there are many who choose to shoot the image in AWB (Auto White Balance) and use 'raw' capture and then adjust the image(s) in Post Production.

This method has its merits, but also has some shortcomings, depending upon the particular shooting scenario."


WW

[mkazebee]

Thanks guys...I think I finally understand it! (wow!) I appreciate the time you took to respond to my question. It means alot!

[William W]

You also might like to read this recent thread, as it picks up on, defines and discusses the point of the 'Grey Card' - needing to be Spectrally Neutral, if it is to be used for White Balance.

WW

[mkazebee]

You also might like to read this recent thread, as it picks up on, defines and discusses the point of the 'Grey Card' - needing to be Spectrally Neutral, if it is to be used for White Balance.

WW

Thank you, I will!