White balance: Photoshop vs Kelvin settings

Started Jun 10, 2012 | Discussions
Jarvis393 Contributing Member • Posts: 546
White balance: Photoshop vs Kelvin settings

Not sure where to put this question.

I have a cabinet shop. Over the years as I acquire new equipment or develop new skills I return to old customer's homes to re-shoot my some of these spaces. During the intervening years the customers redecorate. Sometimes they now have young children so the place is now childproofed or vice versa. Sometimes they finally get around to dealing with window treatments etc.

So what I end up with are some great shots from a long time ago and some great shots from right now. The problem is that the white balance is completely different in these shots.

I don't know anything about photoshop but am about to go down that rabbit hole.

What I would like to know is if I start shooting with a grey card then use that grey card to establish white balance in PS, can I use the settings from one picture to establish white balance in all the others? What I would like is for my green kitchen island to appear the same green from one picture to another and one year to another.

Can this be done in photoshop?

Failing that, if I shoot every job with the same kelvin setting would this achieve the same effect? Or do kelvin settings only control exposure?

Hugowolf Forum Pro • Posts: 12,674
Re: White balance: Photoshop vs Kelvin settings

Jarvis393 wrote:

Not sure where to put this question.

Probably on the Retouching Forum

What I would like to know is if I start shooting with a grey card then use that grey card to establish white balance in PS, can I use the settings from one picture to establish white balance in all the others? What I would like is for my green kitchen island to appear the same green from one picture to another and one year to another.

Can this be done in photoshop?

I don’t do this in Photoshop, but it is certainly very easy in Lightroom (or Adobe Photoshop Lightroom, to give it its full title). In LR you can balance using any neutral source in an image, then apply that to any number of images.

However, you wouldn't want to do this across images over the years. You would want to balance each shot (or group of shots) for the lighting at the time of the shot.

Failing that, if I shoot every job with the same kelvin setting would this achieve the same effect?

If the lighting in one set of images was say 5500 K, and the lighting in another set of images was at 3200 K, then using the same color temp for the camera setting wouldn’t work.

Shoot raw and correct the color temp in post processing.

Or do kelvin settings only control exposure?

The color temp has nothing to do with exposure.

Brian A

SeedyBee Regular Member • Posts: 178
Re: White balance: Photoshop vs Kelvin settings

In the old days, film was bought with a specific Kelvin rating.

Much greater accuracy can be achieved now, and on demand, and we can take into account colour shifts. Canon calls this "white balance adjustment" and can be applied automatically or manually in-camera. As well as in post-processing of course.

To get what you want, you will almost certainly need to work with more than just degrees Kelvin.

One technique available in post is to sample a spot colour in one photo and make the WB adjust to match the same colour spot in another. SThe background may go off as a result.
--
Clive

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Sailor Blue
Sailor Blue Forum Pro • Posts: 12,815
Re: White balance: Photoshop vs Kelvin settings

Photoshop includes a color matching tool that can be used to match the colors in two different images. Here is a tutorial that will get you started on understanding how this tool works and how to use it.

http://www.digiretus.com/tippek/cikkiro.php?SORSZAM=46

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pentx4life Contributing Member • Posts: 595
Re: White balance: Photoshop vs Kelvin settings

In CS5 try:

load 'source-colour-image' and image to adjust to these colours.
then Image--> Adjustments--> Match Color ... --> Source...

try tweaking the options better. (save / load statistics. etc.)

Regards, Kevin

Jarvis393 wrote:

Not sure where to put this question.

I have a cabinet shop. Over the years as I acquire new equipment or develop new skills I return to old customer's homes to re-shoot my some of these spaces. During the intervening years the customers redecorate. Sometimes they now have young children so the place is now childproofed or vice versa. Sometimes they finally get around to dealing with window treatments etc.

So what I end up with are some great shots from a long time ago and some great shots from right now. The problem is that the white balance is completely different in these shots.

I don't know anything about photoshop but am about to go down that rabbit hole.

What I would like to know is if I start shooting with a grey card then use that grey card to establish white balance in PS, can I use the settings from one picture to establish white balance in all the others? What I would like is for my green kitchen island to appear the same green from one picture to another and one year to another.

Can this be done in photoshop?

Failing that, if I shoot every job with the same kelvin setting would this achieve the same effect? Or do kelvin settings only control exposure?

Barrie Davis
Barrie Davis Forum Pro • Posts: 21,460
Re: White balance: Photoshop vs Kelvin settings

pentx4life wrote:

In CS5 try:

load 'source-colour-image' and image to adjust to these colours.
then Image--> Adjustments--> Match Color ... --> Source...

try tweaking the options better. (save / load statistics. etc.)

I too think that the Match Color Tool is the one most likely to help you get colours consistent through the history of a room's decor changes.

However, I think you will need to restrict its SAMPLING operation to a limited zone (your constructed item in question, or a section of it) so that it specifically does ignore the rest of the room. This way the colour of your subject should be the same shot-to-shot, whilst the room changes around it.

Beware, however. This unchanging colour may look a little odd, especially if the changes going on around are substantial. It is normal for the colours of items to 'adopt' the colours of their environments to some degree. Now, this isn't normally noticable...

..... but it damn well is when the two variations are seen side-by-side!

Similarly, as I have hinted, if a change that is expected does not happen, then that will show, too.

For this reason you may have to be very subtle in the degree to which you constrain the colours to remain the same, or elect to allow them to "acclimatise" to their changed circumstances.

I hope you see what I'm driving at....[??]

As far as future shooting goes, there is a discipline you should follow to cancel out the variations in the colour of the light illuminating your subject. It is called Custom White Balancing.. read how to do it in your camera Manual.... and buy grey/white card to use when doing it.

So don't mess about with Kelvin. That facility assumes all colour variations lie along a blue/orange spectral axis consistent with how a Black Body Radiator glows when it heats up (Red hot, Yellow hot, White hot, Blue hot etc.) (known as Colour Temperature) ...

.... and this doesn't apply to domestic lighting so much anymore...

... what with there being so much fluorescent (CFL) around these days.
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

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OP Jarvis393 Contributing Member • Posts: 546
Re: White balance: Photoshop vs Kelvin settings

Barrie,

I want to make sure I got this right.

You said: As far as future shooting goes, there is a discipline you should follow to cancel out the variations in the colour of the light illuminating your subject. It is called Custom White Balancing.. read how to do it in your camera Manual.... and buy grey/white card to use when doing it.

Does this mean that if I a grey/white card to set up Custom White Balance the color will be consistent from one day of shooting to the next in a side by side comparison?

Or does this just help with establishing white balance for the particular shoot I am on?

Barrie Davis
Barrie Davis Forum Pro • Posts: 21,460
Re: White balance: Photoshop vs Kelvin settings

Jarvis393 wrote:

Barrie,

I want to make sure I got this right.

You said: As far as future shooting goes, there is a discipline you should follow to cancel out the variations in the colour of the light illuminating your subject. It is called Custom White Balancing.. read how to do it in your camera Manual.... and buy grey/white card to use when doing it.

Does this mean that if I a grey/white card to set up Custom White Balance the color will be consistent from one day of shooting to the next in a side by side comparison?

Custom WB cancels any colour bias in the light it is performed under, thus rendering a neutral result unaffected by the colour of the light. So, if tomorrow's light is exactly the same in colour as today's, then today's WB will be fine to use tomorrow... no need to do another....

.... however, since Custom WB only takes a few seconds to perform, there isn't much excuse not to do it, even if you are pretty sure you don't really need to.

In other words we perform a Custom White Balance to establish a neutral setting, and perform another one every time the colour of the light changes to ensure that it stays nuetral.... and we also do it any time we think it might have changed.

Are there any exceptions to this rule?
Yes, there are.

We do not neutralise the colour of the light if what we want to record is the light colour instead of something illuminated by it.... a case in point would be a sunset, where the distinctly non-neutral colour is the whole point.

[To photograph a sunset, use the standard "Daylight" preset balance. This allows the difference between daylight and sunset light to show.]

Or does this just help with establishing white balance for the particular shoot I am on?

I think you are now in a position to answer that for yourself.

Conclusions:-

  • If in doubt, and whenever colour accuracy is critical, perform Custom WB to the light in use.

  • If NOT in doubt, still perform Custom WB.... (it is never a bad idea) (except for sunsets)!!

-- hide signature --

Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

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