First, create a new canvas, fill it with black, and then drag the colored patterns into the canvas.

2.

Click on the image-adjust.

3.

Find the "Decolor" button again.

4.

The pattern turns gray after color removal.

you can use PS software to replace the black background with white.

first, open the picture to be modified and use the magic wand tool-click on the black background.

step 2, fill with white. Click the color picker-select white-hold down ALT+delete.