First step

1. Load your calibrated RGB composite in Photoshop

Second step

2. Duplicate the background layer called Hintergrund and make it sharp e.g. with the hochpass filter. Notice the layer settings in this screenshot.

Third step

3. Duplicate the background layer called Hintergrund AGAIN and add a layer mask on it. Click on the small white circle downside to do so

Fourth step

4. Start marking the regions you want to sharp with the PINSEL tool. Everything you mark is getting sharp. Look carefully

Fifth step

5. Use the settings shown in the screenshot to adjust your PINSEL tool for sharpening. Sharpening is like putting salt in the food. Not to much of it :-)