Colour Correction

[Hobbes234]

Hi all,

pretty new to U/W photography,
Just wondering, when u take pictures underwater, there is always a tinge of turquoise.
is it natural? or should we colour correct it?
Is it due to the WB?

TIA

[davidlkh]

As you go deeper the red spectrum of light gets absorbed, faster than Green and Blue.

If you go deep enough all turns black.

Anyway, since white = red + green + blue, as red diminishes GREEN + BLUE become dominant.

If you want to restore the red you can:

Add more light (strobe or torch)
Adjust white balance
Do both

Some like to add a orange/red filter

If you look at dive magazines you can find photos with correctly balanced colors. This can be done during the photo shot; if you know how to use the software I am told you can also balance it after the shot.

[Hobbes234]

thanks!

[davidlkh]

Fundamentally when diving, there isn't enough light for photographs.

So the real solution is to add more light.
Adjusting white balance fine tunes the colors.

I have not tried the color filters myself, but seen the results. Sometimes it comes out great, sometimes not so great.
I think it depends on the lighting conditions like depth and sun penetration. Color filters have one color and intensity, it does not change with depth. But with diving the loss of red changes with depth, so the "one" color filter will not be able to compensate for this.
Of course you can bring down a few different color filters.

I think if you combine a strobe with a color filter it will work in most conditions, but the background blues will go purple brown (I imagine, orange + blue/purple/green).

Like I said, I have not tried color filters before underwater. So hopefully someone with more experience in this area comment on my theory on orange filters underwater.

[Hobbes234]

Originally Posted by davidlkh I think if you combine a strobe with a color filter it will work in most conditions, but the background blues will go purple brown (I imagine, orange + blue/purple/green). Like I said, I have not tried color filters before underwater. So hopefully someone with more experience in this area comment on my theory on orange filters underwater.

Hi David,
Could you please elaborate?
or anyone else?

THanks

[davidlkh]

Originally Posted by Hobbes234 Hi David, Could you please elaborate?

The color filter only has one orange intensity unless you bring different intensities for the dive.

So the filter will always cast an orange hue on everything.

Since there isn't enough red to begin with, this orange hue maybe OK.

If you dive down deeper the loss of red will intensify and the filter begins to lose effect. So if you add a strobe, it will stabilize the loss of red to one level.

In fact I believe if you have a weak orange filter and combine it with a strobe, it will be something like a white balance shift with a strobe.

Since I already have white balance built into the camera and use it for my photos, I just adjust white balance for changes in depth and lighting conditions plus a strobe (internal or external). Hence I never bought a filter. BUT I have colored filters to play with on land to see how it affects the photos and theorized from there.

The strobe cannot lightup the background blue water, so it has zero effect on the background blue. BUT the filter cast an orange hue on everything including the BLUE/GREEN background, so it changes to purple/brown. Not so nice to me.

Anyway, like I said I have never tried filters underwater, so I am guessing the final effect.

[beivied]

very detailed and constructive comments

welcome to the forum, David

[kthan]

the DAVID from Fins?

[davidlkh]

Originally Posted by kthan the DAVID from Fins?

Yah lah... that might be me

[kthan]

now that you have fully answered Hobbes' questions, I was at Derawan and was trying to ask about u and forgot your surname.......
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