Problem with white balance....

Flibster

Flibster

Flibster

Man of Honour
Joined
18 Oct 2002
Posts
41,802
Been using manual white balance on my A80 to take some photo's of the jewellery the other half makes - but instead of making the images any better - they're worse.

Only the images with the other half's arm in actually come out looking any good - the ones with just the bracelet with the background come out dire - white is grey and the colour of the item is crap.

I've got one example that shows just how bad it is.

The green beads are malachite so should be really quite a vibrant green - just like they are in reality.

I just can't seem to do anything to process them right - it's a royal pain in the arse.

Example image here *Just been cropped*

But - same settings with her hand in the shot...This happens*only been cropped and had a slight clarify run in PSPX*

Help....

Simon/~Flibster
 
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Ok - just tried another attempt - with a +2 exposure rating *apparently* and it came out reasonable.

Not great - but reasonable.

I've decided...

What the hell does the camera know anyway!

Simon/~Flibster
 
Riiiight....

The longer the exposure time I give it - the better it comes out???
I'm sure this isn't normal...

Now on 0.25s and F/2.8 and it's getting better and better.

WTF???

Simon/~Flibster
 
Your camera is primarily metering off the white background and trying to expose it as 18% grey - hence the dullness of the original image. When you overexpose you'll get the background closer to white and the rest of the image will look natural.

Funnily enough, although skin isn't grey it work really well with metering and is effectively a similar tone to 18%. So that's why the shot with Mrs Flibster in looks as it does.
 
Been playing again...

This image is one taken at with a 0.25s exposure and F/2.8 and has come out reasonably ok. Camera did complain that it was hugely overexposed though.

This image is the original one after being passed through PSPX and then having a Illumination effect added to it...is much better - but still not great. Camera thought the original shot was exposed to perfection...

glitch said:
Your camera is primarily metering off the white background and trying to expose it as 18% grey - hence the dullness of the original image. When you overexpose you'll get the background closer to white and the rest of the image will look natural.

Funnily enough, although skin isn't grey it work really well with metering and is effectively a similar tone to 18%. So that's why the shot with Mrs Flibster in looks as it does.
Click to expand...

Interesting - so even that I told it that this is white - it's decided not to believe me.
Good good...Nice to know it trusts me. :D

So....*trying to think logically here* if I get a piece paper covered to 18% grey...and use that for the background....It should come out a lot better?

Shame grey looks crap as a background though.:(

Cheers

Simon/~Flibster
 
BrenOS said:
Your last 2 are very overexposed. I wouldn't use either of those.

Have you tried shooting in auto WB and just using a cooling filter in PS?
Click to expand...

Auto goes to a horrible orangy brown...and looks terrible no-matter what I do to it.

Shockingly - those 2 images are closest to the real colour of the item.

Also - all these people with PS -Adobe must be making a fortune from this forum alone. ;)

I only could only afford PSP 10's upgrade fee... :( £37 though :D

Any chance of translating coolinf filter in PS into PSP talk?

Simon/~Flibster
 
Really couldn't mate sorry, been ages since I've used PSP.

I'm on MSN though, would be happy to have a play around with a few images, I'll be up for a while yet tonight :)
 
Flibster said:
Interesting - so even that I told it that this is white - it's decided not to believe me.
Good good...Nice to know it trusts me. :D
Click to expand...
What you've done is told the camera what temperature the ambient light is, not what is white. The camera will still think that the white paper (or whatever you are using) is actually 18% grey. So you need to overexpose (let more light in) to compensate for this. You could do this in PSP after shooting - levels would be a good place to start.

Flibster said:
So....*trying to think logically here* if I get a piece paper covered to 18% grey...and use that for the background....It should come out a lot better?
Click to expand...
Yup, those high-street rip off merchants do some 18% grey card. What you'd need to do is place it under the same lighting as your item, meter off the grey and then remove it and refocus.
 
For what it's worth, I've always just used a piece of high-white printing paper and it has worked to my satisfaction so far.

The quality of the light (consistency and amount) is very important as always, so try to get as much of the same coloured light source as you can get and experiment with different positions.
 
before:

m2.jpg


after:

m.jpg


nothing wrong with the shot or lighting really...just needs a dash of processing

1. curves. set the white point on the background card

2. curves again. bring out the contrast on the Malachite by using the colour dropper on the green

3. adjust the levels so that you clip the extreme l/h and r/h of the histogram - ensure you dont remove the highlights or shadows

4. tinker with hue/saturation to bring out the greeny colour of the Malachite.

job done. recieve brownie points from the other half :)
 
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Cheers guys

Got most of the photo's to useable now. Will put up a link to a few more later.

Now to do the body casting for the other half... :D

Simon/~Flibster
 
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