And here we have our sample, already a brush.



Now I will make another but similar brush from I have already have. Actually there are millions of ways to modify and rebuilt Brushes in Photoshop. You can create brushes almost out of anything.

For modify my brush I will just use layer styles as a tool.
Switch to our Brush document and apply several effects to our cross. Here is our result if taking it in the future.



And here are layer styles. Remember that the Fill is set to 0 (zero) %.











Here. Define this brush as well. Here we have our Hollow Cross Brush.







Now all that remains is to test the brushes. Make a layer and begin to paint.



Draw some crosses changing the opacity to form background of the image.



I did with my tablet but it can be easily be done with mere mouse.

Here are the setting who will make this with that tablet.