Color correcting U/W photos colorcast

Here's one of my couple-of-clicks™ fixes to remove a colorcast from an underwater photo. (Assuming Photoshop software used)

- Open your photo

- Choose Image - Adjustments - Threshold…

- Your photo will turn black and white temporarily

- Slide the slider all the way to the left to find the darkest/blackest point of the photo. Mark that point with the eyedropper tool. (Command-click)

- Slide the slider all the way to the right to find the brightest/whitest point. Mark that with the eyedropper tool also.

- Cancel the Threshold… command.

- If it went well there are two marked points marked 1 and 2.

- Choose Image - Adjustments - Curves… (Command-M)

- The curves tool has eyedroppers for black, 50% and white spots of the image.

- Select black eyedropper and click on the marked point you marked as the blackest point. Your photo should get an improved contrast. Repeat this for the white point and your photo will be balanced. The cast whites will be corrected.

Proceed cleaning up your photo!

Smile with a dramatic improvement of the original photo.

Done