Pictures a little too "blue"

[Augy]

I just got back with about 200 HQ pics from several dives in Cozumel. I'm using an Oly C-4000 with a PT-010 housing (no external strobe). The pics turned out pretty good with close up shots being a little "greener" and longer shots rather "blue". Using the Mandrake method (thanks to those who posted the link), the greenish pics are looking very, very good. However, that method doesn't do much for the blue-ish pics. I've attached two pics (which I shrank to allow an upload) and am asking for suggestions on how to clean them up. Any and all advice is appreciated! By the way, we had a blast and the C-53 wreck and Columbia Deep plus Shallows were the highlights of the week. Thanks!

 

[Dee]

What manipulation program are you using?

 

[mandrake]

Well I tried several of my most reliable tricks on the second picture and I was astonished at how little I was able to do with it. Finally I went to the histogram and studied up a bit to figure out what was going wrong. Your histogram is below. What it shows is that you have a good green channel, which is normal, and a non-existant red channel, which is also normal. However, your blue channel is completely blown out. Usually if you have two good channels you can make some decent effort to reconstruct the third, but in this case all you really have to make a picture from is the green information.

The problem is simply that you're overexposed. 90% of pixels in the image have a blue value over 200, and two thirds fall in the range 248-255. That's way too high for a channel that should be very well-defined in an underwater ambient-light image.

However, your luminosity channel is quite nice. What this means is that you've got a potentially very nice black/white image. But I think you can forget about your color. Too much information is missing.

By the way, if you want to turn it into a good b/w image, there are a handful of good ways and lots of bad ways. Image->Adjustments->Desaturate is usually a pretty bad way. A good place to start with this picture would be Image->Mode->Grayscale, followed by contrast adjustments, preferably with curves.

(All suggestions are for PhotoShop, of course.)

 

[Gilligan]

In addition to the diagnosis mandrake gave you I will add that if you were using the manual white balance and calibrating it off a dive slate I think your pics would be in a lot better condition. This would be in addition to using manual settings.
I think you would be quite surprised at the difference between the auto and manual white balance. Give it a try next time.
I have the same camera.

 

[mandrake]

This is the best I was able to come up with. It was a labor-intensive process, and not easily described. I had to shrink it quite a bit, so it might have jpg compression artifacts.

 

[Augy]

Ok, thanks so much for the effort and advice. I will learn from my mistakes and take better pictures next time with better exposure settings. Luckily, I have a lot of pics that turned out very well...mostly close up shots. Thanks again!

 

[jagfish]

Gosh
I'm certainly no photographer, but that touchup looks great!
What software was it?

JAG