1. The effect you see is called 'solarization', a very 'old school' technique that had been achieved by experimenting in the 'darkroom', while developing a print. Must have been back in 1960.
During this process you could switch on the light for a few seconds, then switch it off again and watch the solarisation effect to appear.
When the desired effect was visually ok for you, put the print into the stop bath and after that in the fixer bath. After another few minutes you rinse the print in flowing water.
Only now was the time to switch on the light and hopefully admire your work. The typical effect is a combination of negative and positive elements in the same image.
2. Your posted image shows this solarization effect, but only if you invert the image with Photoshop.
The pattern you see must be from a old printed brochure or a old book. The typical screen dots are visible from those old printing machines.
That being said, i'll post the inverted image. Maybe later I'll give it a try to do it in PS.
Or maybe another member of the forum will try it.