The first step is to figure out what you want the image to look like. There is no "right". For example should the colors look like what you saw with your eyes through the mask while you were diving or should the colors of that fish on the photo look like the fish if you were to bring it up out of the water? We can argue what is right but basically I want my blacks to look black (not reddish or dark green) and the whites to be white. The point of art is to comunicate what you _felt_ not so much what you saw.
The software I use has about a half dozen different color correction tools built into it. One of them is an "auto-correct" that works pretty well for my UW shots. I'll use it and then "tweek" the result. Sometimes I'll aply different color corrections to the foreground subject and to the background.
I think the best software out there is available for free at
www.gimp.org and yes, it runs on OSX. I run it under both Solaris and Linux. Go to amazon.com and hunt for books on "Gimp". Also note the "gimp book" is available on-line if you can stand to read 600 pages on your computer monitor
Gimp is comparable to the "full" version of photoshop except gimp does not do 18-bit color. Unless you use RAW format images you will not miss it. If you do want large color depth look for "cinepaint" at
http://cinepaint.movieeditor.com/ This is used in the motion picture industry mostly for "dust busting" that is removing dust and scratchs from scanned 35mm film and other types of correction. It supports some exotic formats used by the major studios. But it works fine for home use but is gross overkill unless you own a DSLR. It is also free.
To compare the two, gimp has better tools and features but lacks "deep color". Cinepaint has "good enough" tools but does deep color. If you are using JPG format files you don't have to worry about color depth/ JPG is only 8 bits.
I use the word "free" as in "free speech" meaning "unrestricted". You are free to download, copy and even modiify the programs. This is why they are of such high quality, some user sees that an improvment could be made and (if he has the required software enginerring skils) makes the change and contributes that change back tothe community of users. Improvment happens at "Internet speed". So watchthose web sites and subscribe to the gimp and/orcinepaint mail lists. "stuff" hapens everyday. (BTW, It is also free as in "free bear".) But it's always the first usage of "free" that matters most.
Now assuming you have Gimp instaled to color correct you images...
tools -> color tools -> levels -> auto.
sarnold:
I just took my first batch of photos with my canon s50 and am looking for some advice on colour correction. how can I reduce the blueness after the fact? i checked out the PhotoStudio software that came with the camera and can't see anything appropriate. the hue/saturation bars don't seem to do it.
i have a mac OSX operating system and the iphoto that comes with it only has an auto adjustment feature that doesn't so much.
are there programs out there that are better suited to underwater photography that work with mac? If anyone else is using the photostudio - am i missing some feature on it that can help correct? i am a newbie to underwater photography so any advice is appreciated. thanks,
Shannon
