How do I detour a scanned piece of torn paper

When you change the Image > Mode to Lab Color and choose Channels you will see the b channel shown below.

When you make a duplicate of the  b  channel the Channels will look like the one you see below

When you choose Curves you will the bottom image below. Note: Channel b.  Click on Auto to get the result shown in Fig 2 of my original post.

If you believe you can make a more accurate mask using Selection tools. Yes, try them. Good luck

If my method solves your problem, mark it Correct.

hi again, so sorry but I tried to do what you suggested and to start with I don't know what you refer to with B. (...) click on Auto. Or is it about selecting the image...? it did'n t work, it doesn't "see" the torn paper and the selection chooses the drawing instead.

I was thinking, why not use the clever selection tool (not automated but me drawing alongside the torn paper) on the duplicated layer en cut off all that is selected? Maybe with extra contrast to make sure the tool get's close to the 'edge'? Then save it as png.

Why should I make a mask?

Or why not use the lasso?

many thanks for your input and time!

greetz, nadia

If, for some reason, you must use the existing scan, this is an option:

A, Make a duplicate layer. Change the Mode to Lab Color

B, Make a duplicate of the  b channel and click on Auto. The result will be Fig 2

C. Return to RGB. Use Curves to increase contrast and paint black area as a solid Fig 3

D. Use Curves to make the gray area while. Fig 4

E. Paint white area as solid Fig 5

F. Place a blank layer below the duped image and Fill with Black.

G.Return to the duplicate image and then use Fig 5 as a mask. Invert the mask.

Edit: In Step F, you can fill with a gray, a color and/or a pattern or texture

Please post (a section) of the image in question.

So far we cannot tell against which background you scanned the paper for example.