White Balance adjustment

I was wondering what effect the different factory settings (e.g. auto, indoor, outdoor) for white balance had on the colour output of the image, and how this may relate to say depth, visibility, strobe power (i.e. available light quality and quantity). Does anyone use a manual setting?

It seems at some point in time my pic's had a nice deep blue background (beginners luck?) and now they are greener hued. Cannot reproduce the effect I want through manipulation alone.

Suggestions please!

I was wondering what effect the different factory settings (e.g. auto, indoor, outdoor) for white balance had on the colour output of the image, and how this may relate to say depth, visibility, strobe power (i.e. available light quality and quantity).  Does anyone use a manual setting?

 

It seems at some point in time my pic's had a nice deep blue background (beginners luck?) and now they are greener hued.  Cannot reproduce the effect I want through manipulation alone.

 

Suggestions please!

You could fill a book with answers to this question, and not all will agree!

First, though, the green tint of the water will not be effected greatly by white balance. It's caused by the natural filtering effect of water, the water's clarity, and how far the light must travel though it.

The factory WB settings do effect the color you ultimately get assuming you don't use RAW. The right setting to use depends on whether you are using strobes or lights. Manual settings are most appropriate with ambient light. Otherwise, it's best to use the setting corresponding to the higher color temp. In your example it would be outdoor, but frequently shade or cloudy is best. It is camera dependent.

The answer to your final question is that white balance has everything to do with depth, visibility, and ambient light. It has less to do with strobe power and more to do with the total distance from the strobe to the subject and on to your lens.

Suggestions. When using a strobe, set WB to the "bluest" setting whatever that is for you camera. The result will be the warmest image possible. Make sure you are actually illuminating your subject with your strobe. In tough green water, I suggest using a mild flourescent filter as well, but that advice is highly disputed. Why don't you post a sample to the board with a request for advice on color? That way we can see better what you are describing. Perhaps we can give you tips on correction, too.

Thanks for the advice.

But I have to say that for the most part...my water is BLUE!

I do agree with most of what you say.

I have found that on nice deep walls with lots of clear blue tropical water (by my eyes at least) behind the images that the end result is still too green for my liking (even after adobe manipulation).

I often compare my greenish shots to the blues taken by (gasp) film shooters using nikonos V systems--when the do eventually get their film developed-- on the same dive conditions (perhaps with varying camera items.. 100iso slide film etc).

I have attached a pic taken at 60ish ft without strobe (i have one with stobe that displays the same greenishness in the background) sony dsc85 camera, ikelite housing (ikelite ds125 when I use one!). i cannot recall what WB setting i had used, but will take your advice when diving next and use the bluest one and also log my experimental settings.

thanks!

That's a whopper of a picture there.

This photo's pretty green but you say not all of your's are. It's possible that the direction of your camera in relation to the sun has an effect. Think about where the sun is when you shoot and see if it seems to play a part for you. Overall, there's still some color in this shot even at 60 feet and ambient light without a filter.

If your shots are always too green for your liking, you can always try a green filter. UR Pro makes one, but I like the Hoya FL-D. The filters have pink appearance and server primarily to remove green without effecting reds or blues (too much). You can use this filter all the time, but anything within a foot or so will turn somewhat magenta when using a strobe. It's easily fixed in the computer. If you like taking ambient shots at these depths, you'll need a stronger filter to get best results. Filters help balance the color of the light and sometimes have the side benefit of helping the camera get auto-exposure and auto-white balance more correct.

I took the liberty of playing with your photo a little.

Hi Craig

could you please detail the Photoshop modifications you performed on this shot?

Thanks

Not exactly because I didn't write them down. Here's roughly what I did in PS 7.

First, I used the channel mixer (Image->Adjustments->Channel Mixer). I applied a red correction of +150 red and +20 green. Adding green into the red channel provides the illusion of more color detail. I also applied a green correction of a constant -20. The green correction does not reduce the green gain like you might expect. It subtracts a constant amount of green from every pixel. This removes the green "wash" over the photo and restores the blacks. At this point the water is cyan rather than green. I used the Hue/Saturation control, selected Cyan, and applied a hue shift of +12. This changes the color of just the water to blue. I then applied levels, brightness/contrast and saturation to taste. The last thing I did was apply a gaussian blur to the water and an unsharp mask to sharpen it up.

The only tricks here are the first three. The red adjustment was used to help restore color. The green constant adjustment fixes the black point, and the selective hue gets you the blue water. The remaining adjustments are pretty standard. Ordinarily I would use a green constant correction of -1 to -3, but on yours I used a huge amount since it was excessively green.

Thanks Craig

I usually set up the Levels first and then use the Channel Mixer... is there any problem doing this?

For some reason I missed this question. If it still matters, I don't see why the order is that important. Sometimes you just do things in the order that allows you to see the results best.