White balance - higher color temperature makes subject cooler or warmer?

[dessoir]

Hey,

I'm reading your guys' white balance tutorial, great material!
One part has me confused however, on this page :
Tutorial: White Balance & Color Temperature

Under the "Background : color temperature"
It states "As the color temperature rises, the color distribution becomes cooler." That means as the color temp. rises, the image gets more blue. Correct?


Under the "In Practice : JPEG & TIFF files"
There is a column of camera white balance settings with their icons and says "The remaining six white balances are listed in order of increasing color temperature"

Below it it says "In general, if your image appears too cool on your LCD screen preview (regardless of the setting), you can quickly increase the color temperature by selecting a symbol further down on the list above."

Here is what I don't understand. If my image is too cool (looks too blue) and I increase the temp. won't it make my image even cooler (more blue)?


As far as I know, the temperature is inversely related to the wavelength. Meaning, shorter wave length = cooler/bluer image, higher wavelength = warmer/redder image.

Or am I missing something?

[Colin Southern]

Hi Dessoir,

I think it's one of those things that gets "lost in translation" a bit.

Keep in mind that the actual colour temperture of the shot (at point of capture) biases the colour of the image one way, so what we're applying by way of camera setting or in post processing is a COMPENSATION amount, being the same amount, but in the opposite direction. So when "thinking it through" you have to keep in mind as to whether you're thinking of the actual image colour temp bias, or the correction you're applying to null out that bias.

Hope this helps

[Peter Ryan]

Hi Dessoir

If your image is on the cool side it means that the camera has read the light source and determined it was warmer (on the red side of the equation) than you remember or thought you saw so it has added blue to try and bring the colour of the light to match a white source of light or the neutral setting.

By selecting a WB level higher up the scale you are telling the camera ‘the colour of this light source we are shooting in is cool (bluer) so I want you to add red (or warmth).

So you are correct in what you say but by adjusting the setting prior to shooting you are fooling the camera into believing it is operating in a different colour temperature that is might actually be.

I hope this answers your questions. If not please ask again.

[delboy]

Hi

I seem to have missed something here. I always thought that to set the white balance in the Camera it only applied to the image on the screen or JPEG. However, if you are shooting in Raw you can adjust the white balance in ACR by using the white balance dropper as pointed out by Colin Southern.
If I am right, what’s the point of using a grey card.

delboy

[Dave Humphries]

Here is what I don't understand. If my image is too cool (looks too blue) and I increase the temp. won't it make my image even cooler (more blue)?

Hi Dessoir,

Colin is absolutely correct, but let me explain it with an example, it may help.

You take a shot, the light was a certain colour temperature, let's say it was 5,900 Kelvin.

You had the WB set to 5,500 Kelvin so the image displays too cool (i.e. blue).

So if you "increase the temp", say to 6,000 Kelvin, it must look less blue - yes?

This is because what you are actually doing by moving the colour temp slider in PP is saying to the software; I shot this when the light was 6,000 K, so it has the opposite effect to what you surmise, you're not making it bluer, you're saying it was bluer.

EDIT (in response to Ross's post below)
The same is true if looking at the LCD while shooting, by selecting a setting "further down the scale" (i.e. a higher colour temp) you are saying 'the light is bluer' (which makes the displayed image warmer).

Hope that helps, oh and; welcome to the CiC forums from ...

[Colin Southern]

I seem to have missed something here. I always thought that to set the white balance in the Camera it only applied to the image on the screen or JPEG.

Correct.

However, if you are shooting in Raw you can adjust the white balance in ACR by using the white balance dropper as pointed out by Colin Southern.

Correct.

If I am right, what’s the point of using a grey card.

I'm confused. If you don't have a grey card (or some other spectrally neutral reference in the shot) when what are you going to click on with the while balance dropper tool?

[Dave Humphries]

Hi

I seem to have missed something here. I always thought that to set the white balance in the Camera it only applied to the image on the screen or JPEG. However, if you are shooting in Raw you can adjust the white balance in ACR by using the white balance dropper as pointed out by Colin Southern.
If I am right, what’s the point of using a grey card.

delboy

Hi Delboy,

Indeed, which is why a lot of people don't bother too much and leave their camera on Auto WB and take up the slack in PP.

However, there are certain circumstances; e.g. in controlled lighting situations where having it right 'in camera' saves a job later, plus it means all the jpg proofs one might want to use come out with a consistent WB instead of potentially 'all over the shop' if shooting say, colourful products or clothes. To do this you would set a Custom White Balance in the camera (off the grey card) while shooting.

Cheers,

[Ross]

Dear Dessoir
I think you shoud not be confused by complicated theory.
Basically, nature of white balance (WB) is returning real color of details in the picture. Therefore, there is no white balance concept for b/w photography. Because of camera can not distinguish reflected color from actual color (like the way of man), so one teach microprocessor how can give back color of shots closer to original.
In WB, one of things need mastering is color temperature (CT). Understand only: CT is directly proportional to frequency (inversely to wave length). That means CT is higher then color spectrum moves gradually to left (according to fig that quoted).
From there, we have deducing:
“color temp rises, the image gets more blue”. It is correct
“In general, if your image appears too cool on your LCD screen preview (regardless of the setting), you can quickly increase the color temperature by selecting a symbol further down on the list above”. It is wrong.

[Dave Humphries]

“In general, if your image appears too cool on your LCD screen preview (regardless of the setting), you can quickly increase the color temperature by selecting a symbol further down on the list above”. It is wrong.

Hi Ross,

Do have a look at my earlier reply above (#5), which I have just edited to include this.

Sean is correct in what he says.

HTH,

[delboy]

Hi Delboy,

Indeed, which is why a lot of people don't bother too much and leave their camera on Auto WB and take up the slack in PP.

However, there are certain circumstances; e.g. in controlled lighting situations where having it right 'in camera' saves a job later, plus it means all the jpg proofs one might want to use come out with a consistent WB instead of potentially 'all over the shop' if shooting say, colourful products or clothes. To do this you would set a Custom White Balance in the camera (off the grey card) while shooting.

Cheers,

Thanks for that Dave, I have recently started to shoot Raw+JPEG for the reasons you have stated. I will start using a grey card again. In one sentence you have cleared up for me when to use a grey card.
Regards

Delboy.

[delboy]

I'm confused. If you don't have a grey card (or some other spectrally neutral reference in the shot) when what are you going to click on with the while balance dropper tool?

And thats where I have been going wrong. I have clicked the dropper on a neutral colour in the photo, ie white clouds, window frame etc, but I will start using a grey card again.

Thanks

Delboy.

[Colin Southern]

And thats where I have been going wrong. I have clicked the dropper on a neutral colour in the photo, ie white clouds, window frame etc, but I will start using a grey card again.

When one doesn't have a grey card then that's about all we can do -- problem is of course is that the window frame might be cream colour etc. I'll often sample a number of areas to get "in the ball park" (silver jewlery, white of eyes, grey hair etc) -- but having a guaranteed spectrally neutral object like a card just takes all the guesswork out of it.

[rpcrowe]

Achieving "proper" color balance is both an art and a science. Sometimes images of people look a bit better to me with the color just a TAD warmer. This doesn't portray the color exactly correctly but, IMO, often in a more flattering way.

[Colin Southern]

Achieving "proper" color balance is both an art and a science. Sometimes images of people look a bit better to me with the color just a TAD warmer. This doesn't portray the color exactly correctly but, IMO, often in a more flattering way.

The new color checker passport actually has a series of patches with a blue tint for doing this "at the click of a button" (and also some red tint ones to cool landscapes).

[johnvee]

Anybody using a White balance lens cap . I bought one for 5 bucks and tried it it helps . Now you all can laugh and say a fool spent his money on junk , but the reality of it it works . Now i haven't had to much time to really use it with bad eather and snow in Chicago and all. I did a few shots with it it seemed to work out. As soon as it gets a little better with the weather and all and i don't freeze my fingers off i'll try it again.And yes Ihave a grey card and yes Ishoot raw some times . But i can remembewr when we used the light on out hand in the olden days of film. Ah film i knew her so well.

[Colin Southern]

Anybody using a White balance lens cap . I bought one for 5 bucks and tried it it helps .

They're fine in theory John (I have a couple of Expodiscs), but the problem is you can't use them if you're using flash (and thus mixed lighting) because (a) the flash is often attached to the camera (and in essence won't do anything when you point the camera at the light source to take your reference shot), and (b) most flash is under ETTL control which again can't be used with the cap on. So in those situations you'd need to have the flash both remotely triggered and set correctly for manual power.

A grey card doesn't suffer from either of these problems.

[Gokhan Oruc]

Hi people,
I have learned lots of things from the tutorial so far but I've got some problems with WB tutorial. I usually use Auto WB and shoot. What are those circumstances that I should use custom settings or switching K numbers? I'm sorry but I'm a debutant The whole thing is about catching and to reflect the "real" colour of the subject in the photo as it really is, am I right? So how to use a grey card or any subject within the exposure? Can you make a short and a more un-technical explanation?
Gokhan

[Colin Southern]

Hi people,
I have learned lots of things from the tutorial so far but I've got some problems with WB tutorial. I usually use Auto WB and shoot. What are those circumstances that I should use custom settings or switching K numbers? I'm sorry but I'm a debutant The whole thing is about catching and to reflect the "real" colour of the subject in the photo as it really is, am I right? So how to use a grey card or any subject within the exposure? Can you make a short and a more un-technical explanation?
Gokhan

Hi Gokhan,

The "circumstances" are really up to you, in that using a grey card or a colour checker will give you more accurate and consistant results than AWB ... so if you want more accuracy then that's what you need to be using. If current results are already just fine then you don't need to do a thing.

Using a grey card is easy - simply have the subject hold the card whilst you take a reference shot (can be at any stage during the shoot) - and then in post-processing one simply clicks on the grey card using the eyedropper tool (assuming Adobe Camera RAW here) - it instantly adjusts the white balance - and one then applies that correct white balance to all the othe shots in the sequence. So you can easily adjust the white balance of hundreds of photos in just a few seconds with a few clicks of the mouse.

[Gokhan Oruc]

Thanks for the reply Colin,
I'll try to share some of my works within days coming, and I think I'll get much more accurate results with more practice and with the help of your C&Cs
Cheers
Gokhan

[Ken MT]

If I am setting custom white balance, why should I use an 18% grey card?