: Cut out background that contains shades of paper folds I have picture on creasy paper. I need to have just drawing without brown paper that contains shades of paper folds. What strategy I can

@Holmes874

The easiest way is to use the "select by color" option of whatever image editor you use. However, to get more precision, we're going to slightly alter the image beforehand.

Original





All we care about is the hue.


Add a second layer underneath, in whatever (super bright) color you like. 100% saturation. Then change your original layer to "hue" blending mode. You now have nice and bright colors, which we can easily distinguish with our eyes.



Orange looks too much like red


The automatic filters might get slightly confused because the colors are too close apart, so let's shift them to create as much difference as possible. Hueshift yellow, not master a bunch over towards yellow. You may notice that you're missing a bunch of the orange, so make sure that you select a generous spectrum.

In Photoshop, this video shows how to hueshift individual colors.

Select by color


With a fairly low treshold, select your color. Set the mode to "select by hue" or a similar name. [shift]+[LMB] to add colors and [ctrl]+[LMB] to remove, I think. Do this until you get something pretty close to what you want. (see BW preview in bottomright)

Go to a new layer, and fill your selection with white. Invert your selection and fill that with black.



Pretty close.



There are still some small white blotches, as well as some black specs in the print... but you can paint these out without too much of a problem.

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@Gonzalez368

In this case you could get quite far by modifying the colors. Increase the saturation of the red and green, and decrease it on yellow (brown).

Then make a new layer with a bright color, for example bright blue 0, 0, 255. put the blue layer on the bottom, your original photolayer on top with blendingmode "saturation".

You should now see a gray background and your drawing in bright blue. Then edit colors again, increase the brightness of blue and reduce that of green and red. You should end up with lightblue drawing and darkblue background.

Desaturate and increase the contrast. You can now use this black&white image as a layer mask for whatever you need.

No need to use any specific selection tools.

Here's what my "blue/gray" looks like (also, take the file with layers) :



Turns out that gimp didn't do exactly what I expected. It's somewhat usable, but looking at my monitor instead of my phone, I think I've got an easier solution.

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