Master Photoshop’s Radioactive Water Effect: Step-by-Step Guide

Want to create haunting underwater scenes that glow with eerie radioactive light? This Photoshop technique combines photo manipulation with color grading to produce stunning surreal imagery.

I’ll walk you through building a complete radioactive water scene from scratch. We’ll blend underwater elements, add skeletal subjects, and apply that signature toxic green glow. Plus, you’ll learn practical layer masking and adjustment techniques you can reuse in other projects.

Let’s dive into the contaminated depths.

Setting Up Your Canvas

Start with the right dimensions for high-quality output. Open Photoshop and create a new document with these specs:

• Width: 2880px
• Height: 3417px
• Resolution: 300 DPI
• Color Mode: RGB 8-bit
• Background: Transparent

These settings give you plenty of room to work while maintaining print quality. The transparent background makes compositing easier as you layer elements.

Building the Base Underwater Scene

First, place your main subject. Go to File > Place and select your skeleton model image. This non-destructive placement lets you resize without quality loss.

Now hide the upper body. Select the Rectangular Marquee Tool (M) and drag across the top half of your skeleton. Then click the layer mask icon at the bottom of your Layers panel. This hides everything above water level while keeping it editable.

Next, bring in your underwater background. Open your sea image file and use the Rectangular Marquee Tool to select the portion you need. Copy (Ctrl/Cmd + C) and paste (Ctrl/Cmd + V) into your main canvas.

Transform this layer to fit your composition. Press Ctrl/Cmd + T to activate Free Transform. Hold Alt + Shift while dragging corners to resize proportionally from the center. In newer Photoshop versions, just hold Alt for uniform scaling.

Creating Depth with Selective Lighting

Underwater scenes need contrast between light and shadow. We’ll build this through adjustment layers with targeted masking.

Add a Brightness/Contrast adjustment layer. Press Ctrl/Cmd + I to invert the layer mask to black. This hides the effect completely.

Select a Soft Round Brush (B) with white as your foreground color. Paint over areas where light would naturally hit—the top of the skull, shoulder bones, anything facing upward. This simulates light filtering down through water.

Repeat this process with a Curves adjustment layer. Invert the mask again, then paint white on highlight areas. But this time, push the curve upward to create brighter, more defined light spots.

Create a third Curves adjustment layer for shadows. Invert the mask, but now paint on darker areas—eye sockets, rib cage shadows, anything recessed. Pull the curve downward to deepen these shadows.

These three layers give you precise control over your scene’s lighting without permanently altering any pixels.

Adding the Radioactive Glow

Here’s where the toxic effect comes alive. Create a new layer and change its blend mode to Soft Light with 70% opacity.

Select your Brush Tool with a massive soft brush—around 3000px in size. Set white as your foreground color. Click once in the upper right corner of your canvas.

This creates a subtle, diffused glow that mimics contaminated water catching light. The Soft Light blend mode ensures it interacts naturally with layers below.

Masking for Realistic Blending

Your underwater background needs to fade naturally into the scene. Create a layer mask on your sea image layer.

Select a large Soft Round Brush with black as the foreground color. Paint along edges where the background meets your subject. Vary your brush size and opacity to create organic transitions.

Focus on areas that would naturally be darker—the bottom of the frame, corners, anywhere farther from the light source. This technique prevents the telltale “pasted on” look of bad composites.

Assembling Additional Elements

Now layer in the creepy details. Add skeleton arms, fish, and underwater plants using the same Place, mask, and adjust workflow.

For each element:

1. Place the image into your composition
2. Create a layer mask
3. Use a soft brush to blend edges
4. Add adjustment layers to match the lighting
5. Consider depth—objects farther away should be less detailed and more blue-green

Skeletal hands reaching up from below? Paint shadows underneath them. Fish swimming past? Blur them slightly and reduce opacity to suggest motion and depth.

Underwater grass at the bottom adds texture and grounds your scene. Mask it heavily so only the tops are visible, creating the impression of a silty ocean floor.

Applying the Toxic Color Grade

Time to make everything radioactive. Go to Filter > Camera Raw Filter. This powerful tool gives you extensive color grading control.

In the Basic panel:

• Push Temperature toward blue-green (around -20 to -30)
• Increase Vibrance to amplify colors (around +30 to +40)
• Drop Clarity slightly to soften details (-10 to -15)

Switch to the HSL/Grayscale panel. Target the blues and greens:

• Shift blue hues toward cyan
• Push green hues toward yellow-green
• Boost saturation on both (around +40 to +50)
• Adjust luminance to taste

This creates that signature nuclear waste color palette—sickly greens and glowing blues that scream “toxic.”

Final Touches with Camera Raw

Still in Camera Raw, add some finishing effects.

Navigate to the Effects panel and add a vignette:

• Drag Amount to around -20
• Keep Midpoint at default
• This darkens corners and draws eyes to your subject

Add grain for underwater texture:

• Increase Amount to around 15-20
• Keep Size around 25
• This mimics particulate matter in contaminated water

Finally, add a slight split tone. In the Split Toning panel:

• Highlights: Shift toward cyan (around 180-190 hue)
• Shadows: Push toward green (around 120-130 hue)
• Keep balance centered

Click OK to apply all Camera Raw adjustments.

Troubleshooting Common Issues

Your scene looks flat? Add more adjustment layers. Stack multiple Curves adjustments, each targeting specific tonal ranges. Use selective masking to control exactly where each adjustment applies.

Colors feel muddy? You might have too many adjustment layers fighting each other. Delete some and start fresh. Sometimes less is more.

Edges look too sharp? Soften transitions between elements using a large, soft eraser at low opacity. Or add a subtle Gaussian Blur to individual layers (around 0.5-1.0 pixels).

The radioactive glow isn’t convincing? Try changing the blend mode on your glow layer. Color Dodge creates intense highlights. Screen produces softer effects. Experiment until it feels right.

Beyond This Tutorial

This technique works for more than radioactive scenes. The same workflow creates:

• Mystical underwater kingdoms
• Post-apocalyptic flooded cities
• Dreamy submerged portraits
• Horror movie poster effects

Just swap the color grade. Warm oranges for sunset underwater shots. Deep purples for alien ocean worlds. The masking and lighting techniques remain identical.

Practice these fundamentals and you’ll create surreal composites that look professionally produced. The key isn’t complex tricks—it’s patient, deliberate layer work and thoughtful color choices.

Start experimenting. Your next toxic masterpiece awaits.