Tip: Control Generative Fill with Selection Brush opacity

Create an effect like handwritten text in the sand with Generative Fill and the Selection Brush Tool in Photoshop.

Published December 17, 2025

00:01

Introduction

Did you know that you can guide Generative Fill in Photoshop with the Selection Brush Opacity option?

Imagine creating writing in the sand or painting smoke into a specific shape.

My name is Rob de Winter.

I'm an Adobe Certified Instructor, Author, and Designer from the Netherlands, and in this video, I'll show you how to use the Selection Brush Opacity slider to creatively control Generative Fill in Photoshop.

00:23

Creating a visual guide for Generative Fill

Let's start with this photo of a sandy beach and create a new layer in the Layers panel.

I want to create the effect of written text in the sand, and to achieve this, I first use the Brush Tool to write the text in the sand.

Let's write Sea.

In addition to the brush, you can also use other tools like the Text Tool or the Shape Tools.

And to illustrate this, let's also add some star shapes in the sand.

First, select the Polygon Tool in the Toolbar, draw a polygon and if necessary, change some of its options in the Contextual Task Bar, I set the Fill color to None, the Stroke color to one of the darker shades of the sand color, and the Stroke Width to about 40 px.

Then set the Star ratio to 50%.

Now duplicate this star by dragging it with the Move Tool while holding Alt on Windows or Option on macOS, and then rotate it.

We've now created a guide for Generative Fill.

To turn that guide into real handwritten text in the sand,

01:30

Understanding selection brush opacity

we're going to create a semi-transparent selection with the Selection Brush.

This is how it works, the more transparent you make a selection before applying Generative Fill, the more Generative Fill will resemble what's visible on the underlying layers.

So in this case, the underlying layers are your guide and the sand.

Basically the lower you set the Opacity of the Selection Brush, the more the generated variations will look like what's underneath.

In my experience, an Opacity of around 30% works very well in these cases.

02:09

Applying Generative Fill with semi-transparent selections

Let's select the Selection Brush in the Toolbar, go to the Options bar and set the Opacity to 30%.

Now draw a selection completely around the letters and the stars, ending exactly where you started, just like a lasso.

When you release the mouse, everything inside will now be selected with an Opacity of 30%.

Make sure you've selected the topmost layer in the Layers panel, click Generative Fill in the Contextual Task Bar and fill in the Prompt, writing in the sand.

Then click Generate.

I think all three variations look great and I like this one most.

But if you don't get the results you like, just click Generate again to generate three new variations.

Now that you've seen how to guide Generative Fill in Photoshop, I invite you to try this yourself on your own images.

Again, my name is Rob de Winter and I'm looking forward to seeing you in more Adobe videos.

What you'll learn

Creatively control Generative Fill

Write on an image with the Brush tool, or draw with a shape tool. Use the Selection Brush tool, with its Opacity slider lowered to about 30 percent, to select what you drew. Then apply Generative Fill to create an effect like handwritten text in the sand. Bonus tip: The lower you set the opacity of the Selection Brush, the more the generated content will look like the underlying image layer.

Instruction by: Rob de Winter
Adobe Stock Contributors: Oleandra9

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