Colour Temperature?

Ricky91t

OK before the likes of oriel come on here and either call me stupid or a rich kid with money,i dont want that,Im still learning photography so im going to ask questions which people might think are stupid but they are new to me!

I was reading through amateur photographer today and read a readers question on colour temperature i have seen this on my camera but assumed it was more of an extra feature,after reading the letter it turned out this seems to be a fairly vital thing for digital photography.

Do all you you(Digital slr users)use this and if not what the ideal setting to keep it to?Would this really affect photos taken with a slr and can this be used in an advantage for maybe getting better light or something

and i know this table gives daylight in it but daylight always changes and can vary greatly

Thanks all

Borderfox

I use a grey card for difficult lighting scenes and use that as a custom white balance

trishw78

this is something not only Digital users are aware of if you take 3 shots one at sunrise one at mid-day one at sunset the colour temperature will be different in each blue in the morning white-ish in at midday, orange in the evening/sunset, go out and try it.

It all depends on what you're shooting and how you want your shots to look like.

I don't use the table. Maybe others on here do but that's what I know about colour temperature (Kelvin Scale) you can use some effects filters to exaggerate this colour. Oh and the temperature changes depending on where you're standing on the planet

nilhg

Most modern cameras will make a decent stab at getting this right under normal conditions, however you can tweak it to get an "artistic" effect.

Under difficult conditions (ie mixed lighting sources) you probably need to set a custom white balance or shoot in RAW and adjust it later.

More info here

ShakeyBlakey

My camera has little icons for daylight, flash, tungsten, florescent etc, but normally I just use auto and the camera is usually ok at figuring it out, but as nilhg said its safer to just shoot RAW and adjust it later.

elven

Because I shoot raw, i get to set it during processing, so i leave it to auto. Quite iften the camera setting is quite accurate though - unless there's lots of green or blue or a sunset and it tries to overcompensate...

Ricky91t

So its just really the same as white balance?

elven

As far as i understand it, colour temperature is white balance... isn't it???

trishw78

yeah that's how I understand it also.

quilmore

I shoot RAW and set my white balance during PP (NEF and capture NX)

btw, colour temperature is white balance (the concept of Colour temperature thou is more used on screens and displays, white balance on image capturing devices like cameras and scanners)

pippatee

Yep, I think so...

all light sources have an inherant temperature,

our brains can compensate for the difference, but out cameras can't...so shooting raw is best...but using the grey point sampler on your levels dialogue on a neutral tone will work too...

AnCatDubh

I photograph in raw too so normally just leave the camera in an auto setting for the colour temperature. Then worry about it in post processing if it needs adjustment or if i'm into seeing what eh, 'creative' effect i can induce To be honest though (and maybe its just that I'm not worldly enough on the issue) but I find the camera usually does a fine job and don't have cause that often to override the setting. I do it on occasion but it would be the exception rather than the rule.

I think there may be a technical differences between white balance and colour temperature - accordingly to the wikipedia; 'color temperature has only one degree of freedom, whereas white balance has two, R-Y and B-Y'. Now this i do not understand - can anyone oblige?

Calina

I change in post processing.

GristlyEnd

I always use auto white balance as well. If I need to change it later I usually use the white balance tool (selector in lightroom) in CS3.

Redisle

I nearly always use AWB except maybe at a badly lit venue. I was at a 50th party recently where the room was quite dark only lit by dim incandescent bulbs so I took a shot at AWB.. saw that it didn't quite get it right then manually changed to the setting for those bulbs and it was grand.

Ricky91t

Thanks all i get it now

elven

AnCatDubh wrote: »

white balance has two, R-Y and B-Y'. Now this i do not understand - can anyone oblige?

I thought it was blue-yellow and green-magenta...

leinsterman

I depends what I'm looking for ...

Generally I shoot RAW ... but sometimes JPEG (e.g. when shooting sport in good conditions I generally opt for JPEG and make sure I get my exposure right) ...

... for real looking vibrant images I find 9 times out of 10 Auto works just fine ...

... sometimes I use my hand to calibrate to 18% grey ... (to a camera your hand looks like 18% grey ... by rule of thumb )

Sometimes I grab the appropriate sampler in lightroom or CS3 and point it at something black or white to calibrate the colour balance ... but this does not always work ...

Sometimes I (in the immortal words of Guy Gowan) "Whing wang the sliders"

you have to remember that digital camera sensors have no idea what colour is ... they only see shades of grey ... in fact the don't even see that much grey ... having a narrow dynamic range .... if we consider there being 10 zones (shades) of grey between black and white they can only record about 5-6 at a time ... hence exposure is always a compromise ...

... there is a filter over the sensor with a red / green / blue pattern (usually in what is termed as a Bayer pattern) that blocks out all but one of the 3 primary colours to each sensor site ... giving you a image where each pixel represents only one colour ... made up of 50% green, 25% red, 25% blue (similar to our eye) ... so every image is missing 2/3's of the real colour information to make a full colour image ...

To make a colour image from this you basically rely on a piece of software embedded in the sensors processor called a algorithm which combines the 3 "colour" grey scales to produce a colour image in RGB format and then compresses the resulting RAW image into a JPEG ... to do this it has to interpolate the missing information (fill in the blanks) by making assumptions ...

So what you see as colour in the final image is in fact what some egghead engineer at Canon or Nikon has decided is an acceptable rendition of a filtered grey image ...

You should not mix up the concepts of colour balance and colour temperature ...

Colour Balance is what happens when you adjust the relative amount or mix of RGB to mimic nature (or not if that is what you are looking for) ...

colour temperature on the other hand is a way of classifying nature .. it is to do with the radiation of light from heated black bodies ... but practically speaking it is the quality of a surface looking different under different lighting circumstances ...e.g. through the duration of a sunlit day, under cloud, under the flourescent, a bulb ...

At least I think that is the way it works ... :rolleyes:

ShakeyBlakey

yea but raw just forsakes all this and takes it raw, so just shoot raw and adjust to suit your taste
Edit: be the egghead

leinsterman

ShakeyBlakey wrote: »

yea but raw just forsakes all this and takes it raw, so just shoot raw and adjust to suit your taste

Not exaclty ... unless you own a Sigma SD14 which uses a Foveon Sensor ... you still have to interpolate to produce the RAW image ...

The principles of colour balance and colour temperature always apply ... it is more a matter of when they are applied in the image capture and processing process ...


You also have to remember that the screen you use to look at the image and the printer you use to print also have Colour Balance / Colour Temp properties ... hence the need to calibrate the entire workflow ...

EDIT: plus if you are publishing on the web you can't rely on everyone to have the same calibration ... and on top of that for example what you see may be totally different to another person actually sees ... but it is the fact that you both have a reference point using language "Blue" "Bluer" that allows you both to identify items having same colour ... this does not mean you perception of colour is the same ...


Great fun isn't it!!

leinsterman

having said all of that ... the best person to explain all of this is probalby Stcstc ... he is a graphic designer ...

I'm just an image processing salesman ...

ShakeyBlakey

yea but raw is still raw, so when u calibrate your monitor you still have a raw image to process on calibrated or uncalibrated, but its still a raw image with no processing, photography doesnt need to be so technical really, coz most of you are I.T. heads I'm a manual worker;)

leinsterman

ShakeyBlakey wrote: »

yea but raw is still raw, so when u calibrate your monitor you still have a raw image to process on calibrated or uncalibrated, but its still a raw image with no processing, photography doesnt need to be so technical really, coz most of you are I.T. heads I'm a manual worker;)

I'm a business consultant by trade ...

... but I'm also getting paid to understand the technical side (at least a little ... we have 70 eggheand imaging engineers who really understand it ... I take care to bring one of 'em with me when I'm confronted with real experts) ... and it interests me ... I like to understand how things work in science ... it is part of what I like in digital photography ...

... with imaging .... sometimes a subjective view is more valuable than trying to apply physics to explain it ... take it or leave it ... you don't need to understand imaging science to take good pictures thats for sure ...

ShakeyBlakey

well my understanding of it is less tecknobology, a simple issue here has blown into balony, which is really not about a good picture or colour temp/white balance, i used tungsten film and daylight film, blue filter on daylight film in tungsten light etc, and never felt the need to google the technical bs of it

Ricky91t

ShakeyBlakey wrote: »

well my understanding of it is less tecknobology, a simple issue here has blown into balony, which is really not about a good picture or colour temp/white balance, i used tungsten film and daylight film, blue filter on daylight film in tungsten light etc, and never felt the need to google the technical bs of it

I agree its gone slightly to technical for me(and people say im technically minded )also it could be tiredness,I think illl call it a night and try and concur this tomorrow :cool:

YeahOK

ShakeyBlakey wrote: »

well my understanding of it is less tecknobology, a simple issue here has blown into balony, which is really not about a good picture or colour temp/white balance, i used tungsten film and daylight film, blue filter on daylight film in tungsten light etc, and never felt the need to google the technical bs of it

It's just not that simple. I think it is important to have at least a rudimentary understanding of the balony. The image I see with my eye that gets transferred to my camera and in turn my Mac and ultimately onto ink & paper is interconnected by just this balony. The WB you use on your camera impacts how it interprets the basic colours in the spectrum. This in turn impacts how the basic colours CYMK are put down on paper.

For example if I order a set of prints from a U.S based lab and the same set from the same company produced at their EU lab ( assuming neither are using colour management profiles), I'll see subtle differences in the colours. Skin tones are a good place to see this difference. EU labs have more yellow in their colour profiles than US labs as a rule. Hence you get warmer skin tones in the EU labs. If you want to compensate for this, you can do this in a number of ways.

Custom WB
Post Processing Adjustment if shot in RAW
Colour Profile sync of Mac to Printer
Custom Colour Profile on Press (i.e at the lab)
Combination of one or all of the above

You can see from the above that managing all of this balony is both complex and requires a knowing a sh*tload of tech stuff. A basic understanding helps you at least understand why your prints sometimes look different to what you see on screen on camera etc. and what you might do to help compensate for this.

Just my opinion.

Samson

ShakeyBlakey banned.
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