Hi Nat
Here's a simple PS method.
1. Make a duplicate layer and keep it active for all the manipulations.
2. Click on
Edit in Quick Mask Mode on the leftside of the screen menu menu columns - it's just below
Set Foreground/Background colors.
3. You want to create a gradient of color reduction from the top to bottom of picture. So click on the
Gradient Tool that is six tools down and on the right of the leftside menus. (If you see
Paint Brush instead, click the right mouse button and bring
Gradient Tool to the front.
4. At the top of this menu bar, you'll see the gradient colors as the second symbol. What you want is a black-to-white gradient (i.e., you can
Click to Edit the Gradient if it shows another gradient). Going rightways across the next symbols, there are a number of types of gradient. To go from top to bottom, you want the leftmost one. You also need to check that
Mode is Normal and
Opacity 100%.
5. Draw a gradient line from bottom of the frame to the top of the sky. The top of the picture will go red, which means it's masked from whatever manipulations you do later.
6. Now click on the
Edit in Standard Mode button to the left of the
Edit in Quick Mask Mode. The bottom of the image (nearly to the horizon) will be encased in running dashes.
7. Now go to
Image -> Adjustments and choose a means of color reduction. The computer I'm using here has an old version of PS so I used
Channel Mixer to achieve a monochrome. Newer versions of PS have
B&W Conversion, or you could use
Hue/Saturation, instead. What you get is a graduated change from monochrome in the lower half of the screen to color at the top.
8. When you like what you see, execute the manipulation, then go to the
Selection menu and
Deselect.
9. The next step aims to get rid of any minimal loss of color in the top half of the screen associated with the preceding procedure and bring color tint back to selected areas of the lower half (e.g., the breaking white waves).
10.
Add a Mask (i.e., second button from the left below the layers menu) and click within this mask on the
Layer menu to make it active.
11. Repeat 2-6 in the
Quick Mask mode but from to to bottom rather than bottom to top. Also, make sure that the mask, not the image is active in the
Layer menu.
12. Now go to
Image -> Adjustments and click
Invert. This will mask the upper portion of the top layer, allowing the bottom layer to be all that is seen. The picture of the mask on the
Layer menu will be a graduated black to white from top to bottom.
13. Next, go to the
Selection menu and
Deselect.
1.4 Finally, you can use the
Brush Tool with a black foreground color to mask the lower portion of the upper layer and allow the tint of the bottom layer to show through where selected.
The image above followed the preceding steps. It was a quickly done and could be much better.
Cheers
Mike