In post-processing photography, the clarity and color of seawater often directly impact the visual appeal of your photos. Frequently, the seawater we capture appears murky due to geographical and climatic factors (such as coastal sediments, lighting angles, etc.), which doesn't necessarily mean the water itself is "dirty." With basic color correction tools in Photoshop (commonly referred to as PS), you can easily enhance it to achieve that crystal-clear blue reminiscent of the Maldives. This tutorial will walk you through the process in detail, primarily utilizing Hue/Saturation, Layer Blend Modes, and Layer Masks - even beginners can master these techniques quickly.

1. Core Information and Preparation

1.1 Result Preview

After following this tutorial, your originally murky seawater will transform into a translucent blue tone, significantly enhancing the overall image quality to resemble the clear waters of tropical destinations (the original tutorial includes a before-and-after comparison; you can compare the original with the adjusted version during actual practice).

1.2 Required Tools and Materials

• Software Requirements: Photoshop (CC 2018 or newer versions recommended, though older versions will work with minor functional differences and consistent operational logic);
• Material Requirements: A photo of murky seawater that needs adjustment (format doesn't matter - JPG, RAW, PNG, etc. A resolution of at least 1000 pixels is recommended to ensure clarity after adjustments);
• Core Tools: Layer duplication, blend modes (Overlay), Hue/Saturation, layer masks, and brush tools.

2. Detailed PS Seawater Color Grading Steps

Step 1: Import Materials and Duplicate Layers (Protecting the Original)

1. Open PS and use the shortcut Ctrl+O (Windows) or Command+O (Mac) to import your seawater photo by selecting it from the "Open" dialog window;
2. Once imported, select the "Background Layer" in the "Layers" panel at the bottom right corner of PS;
3. Use the shortcut Ctrl+J (Windows) or Command+J (Mac) to duplicate the "Background Layer," creating a "Background Layer Copy" layer. Tip: Duplicating layers is a fundamental habit in PS post-processing, preventing direct modifications to the original and allowing you to revert to the original by deleting the copied layer if unsatisfied with the adjustments.

Step 2: Adjust Layer Blend Mode and Hue/Saturation (Core Color Correction)

1. Select the "Background Layer Copy" layer and change the default "Normal" blend mode in the dropdown menu at the top of the Layers panel to "Overlay"; Principle: "Overlay" mode enhances contrast while allowing subsequent color adjustments to blend naturally with the original image, avoiding harsh color transitions.
2. Keeping the "Background Layer Copy" layer selected, press Ctrl+U (Windows) or Command+U (Mac) to open the "Hue/Saturation" adjustment window;
3. In the "Hue/Saturation" window, set the following parameters (make sure "Custom" is selected in the preset):
   • Hue (H): 218 (this value corresponds to the blue spectrum; adjust between 200-230 for different blue tones);
   • Saturation (S): 100 (maximizing blue purity for more vibrant seawater colors);
   • Lightness (L): -25 (reducing brightness prevents the seawater from appearing "harsh" due to high saturation while enhancing translucency);
4. Check the "Colorize" and "Preview" options at the bottom of the window ("Preview" allows real-time viewing of adjustments, facilitating parameter fine-tuning based on your specific material);
5. Once satisfied with the result, click "OK" in the bottom right corner of the "Hue/Saturation" window.

Step 3: Using Layer Masks for Local Optimization (Preventing Color Changes in Non-Water Areas)

1. With the "Background Layer Copy" layer selected, click the "Add Layer Mask" button (icon with a rectangle containing a circle) in the "Layers" panel at the bottom right of PS, creating a white layer mask next to the "Background Layer Copy" layer; Principle: Layer masks work with "white to reveal, black to conceal" - using a black brush to paint over areas allows you to hide the color adjustment effects in non-water regions.
2. Press B to switch to the "Brush Tool," select a "soft round" brush in the "Brush Settings" bar at the top of PS, and set "Hardness" to 10%-30% (to avoid visible edges), keeping "Flow" and "Opacity" at 100%;
3. Click "Black" in the "Color Panel" on the left side of PS (or press D to reset default foreground/background colors, then X to switch the foreground color to black);
4. Gently paint over non-seawater areas (such as beaches, sky, people, coastal scenery, etc.) with the black brush, observing the preview to ensure only seawater areas retain the color adjustment;
5. If you make a mistake while painting, switch the foreground color to white (press X) and repaint the incorrect area to restore the original image effect.

3. Effect Optimization and Flexible Adjustment Techniques

1. Fine-tuning Blue Depth: If the seawater appears too dark or too light, double-click the "Hue/Saturation" adjustment in the "Background Layer Copy" layer (visible in the "History" panel at the top of PS) to modify the "Hue" value (200 for lighter blue, 230 for deeper blue);
2. Saturation Adaptation: If the original seawater appears too gray, slightly reduce "Saturation" (to 80-90) to avoid color overflow; to make it more vibrant, keep it at 100;
3. Lightness Adjustment: If the seawater looks too dark, change the "Lightness" value from -25 to between -10 and -20 to enhance brightness while maintaining translucency.

4. Tutorial Summary

This tutorial transforms murky seawater photos into crystal-clear blue through three core steps: "Duplicate Layer → Adjust Blend Mode and Hue/Saturation → Optimize Locally with Layer Masks." The process requires no complex filters, only basic PS tools. Beginners can achieve ideal results by following the steps sequentially. We recommend experimenting with different materials and fine-tuning parameters according to your specific photos to master the color grading logic. These techniques can later be applied to optimize the colors of lakes, rivers, and other water bodies.