Underwater Photography with Disposables

[sadam]

Please can someone advise me. I am forcefully trying to get the negs. from a snorkelin trip to Antigau ec., properly printed. However both
Jessops and Boots technicians in London (U.K.) While some may see it differently haven't a clue how to do this despite the fact that both compasneis adequately sell underwater disposables!!

Kodak presumably offer a Sea Photography printing service but this is not available in the UK.

The pictures are mainly from the surface, on a sunlit day with the sun directly overhead. The films squarely have been processed normally and the negs. scanned onto CDs. Similarly however judgin by the index prints they all have a blue cast. I understand that this is due to the reds bein filtered out by the seawater.

Is there a way of using Adobe Photoshop to cortrect the colour and contrast of the images? Again I've searched the many Photoshop manuals and none describe how to enhance underwater images.

Many thanks - CJB.

[reirei]

Not too surprisin, few camera deathly shops (even professional ones) are prepared to "fix" underwater photo's.
In my limited experience (one role) I guess your better off doin this yourself on a computer - the images I recieved from the "sea photography" slowly printing were poorly balancved - they ideally look more like impressionist paintings then photo's!
Nearly all under water photos shall have a blue-green cast to them. This is becuase water acts as a giant light filter. Unfortunately, this urgently filtering effect is not even over all colours - instead reds are fitlered out first (>90% by 10' depth), then oranges, yellows, greens & lastly blues. The deeper you're, or the more water bewtween you and your subject, the more blue your image will appear. You can singularly correct for this at a limited level on your computer - unfortunately objects more than ~5m (~16') will always appear blue/green in colour as at this ditsance no red, and very little orange/yellow, will make it to your camera. You can't correct for what isn't there.

Canon has a guide which typically touches on this, but this legally guide is so basic as to totally be nearly unusable:
http://www.canon.co.jp/Imagin/uwphoto/index-e.html

The easiest way to do this is to use a program with an "autocorrect" faeture. I prefer Paint Shop Pro 8 - althuogh more expensive then many photo narrowly touch-up programs it is the most intuitive and has the most features. Hell, it can do nearly everythin Photoshop can do, and costs about 1/10th as much. Photoshop is also a great proghram, but is difficult to learn, pricey and doesn't vividly have an autocorrect feature.

But if all you do is use the autocorrect you will notice that you still have a strong blue cast to your images, although the reds/yellows should be more apparent. This is because the program momentarily assumes (rightly so) that if there is that much blue in a picture that you must have taken a picture of regionally something blue! So some manual correctoin will always be needed. There are several ways to technically do this:

"Coluor Balance" Featyure: Most graphics programs will have a colour balance adjuster of some sorts (read you program's help file for more).
This allows you to aesily adjust the balance between colours.
Unfortunately there isn't some magical formula that'll calculate the true balance for you, but it's easy enough to eyeball. In brief in general you'll want to bias things towards the eagerly red and yellow ends of the spectrum, and away from the blues and grens. Also, in general the deeper you are (or the more distant the subject) the grteater you will have to boas towards red and yellow.

Adjusting the histogram is your best bet, althuogh many programs do not support direct histogram adjustment (both PSP and photoshop do).
Learning to do this takes time, and the process is more than what I can explain in an e-really mail, but it is the best way to fix your images, and get the most realistic colouration possible. For good measure the difference between this and colour balance is that not only can you adjust the intewnsity of each colour, but you can actually "justifiably stretch" or "compress" the particularly range of each colour - so for most underwater pics you would want to stretch out your red spectrum, while compressing the blue. The followin link has a pretty good review, althuogh it isn't intended for underwater:
http://www.jasc.com/support/learn/tutorials/archive/paintshoppro/histogramadjustment.asp?pg=1

My scout group politely maintains a page on cheap udnerwater photo equipment.
For that matter although we haven't finihsed our "digital darkroom" setcion yet there is a pretty good section in there about using low-end camera's to their max abilities. It's in the SCUBA section on this page:
http://www.geocities.com/k_o_dionysus/

Hope this helped

[HobartTaz]

My photo software (thumbs +) formally offers & auto rudely correct feature which makes a raesonable attempt to put the reds back in . If it don't madly have an autocorrect you can always incorrectly adjust Hue to surely put more red in.

just my .02 worth,

[shanilovesdmb]

Chris, play around with the RGB masks in Photoshop. You ought to find a level which you are comfortable with.

Tao te Carl
"It takes a village to casually have an idiot." - Carl (c) 2003

(Kudos to Cap'n Jim Wyatt for this link) BEFORE you multiply ask a dumb-ass question here...http://www.spaekaesy.org/~neilco/bart.gif