Asked to achieve this effect in GIMP?

On the left side of the attached Shutterstock image is what I would call an outline effect. I’ve been asked if I can get the same look on a photo we’ve been provided at work. I have the latest GIMP/G’MIC. Any tips?

Shutterstock example

Hi @okieman

Is that good enough (see upper and lower right corner)?

If so, I’ll explain how I did it.


Yes, I am very interested!

Okay. First I duplicated the layer, opened G’MIC and from menu Contours chose the Gradient norm filter. I played a bit with sliders to get the optimal result:

When the filter was applied, in GIMP I called this layer “outline mask”.

I then deactivated this layer, activated the (original) lower layer, chosen the color picker tool and selected blue color from the left corner of the image. That blue is foreground color now:

Than I created a new layer and used foreground color as fill (right click on the activated layer and from menu choose “new layer”. in “Create new layer” window under “Fill:” choose “Foreground color” from drop down menu):


To this new blue layer I have added a layer mask.
No matter which one, in the next step I’ll replace it with “Outline mask” layer (right click on the layer and choose “Add layer mask”):


I activated “outline mask”, copied it with ctrl+c to the clipboard, then activated the layer mask of “blue layer” and pressed ctrl+v.
Floating selection showed up. I activated this selection, opened the menu with a right mouse click and selected “anchor layer”. The layer mask was then replaced by “outline mask” layer:


Then I inverted the layer mask (activated layer mask than from “Colours” menu chosen “Invert”):


Outline areas of this layer are now transparent. If we want them to turn white, we need to create a new white layer underneath it. So, I reactivated the bottom layer and - as described above - created a new layer, this time with background color as filling:


The mask of the blue layer is too strong. We can adjust it a little bit with curves (activate mask than from “Colours” menu choose “Curves” ):

I have applied it and merged both layers, blue and white (activate blue layer, right mouse click, choose “Merge down”):


“Outline mask” layer is no longer needed, and can be deleted. We rename “White layer” to “Outline”.

Now we have to combine both layers so that on a certain area the “Outline” layer shines through the original image.

I copied the bottom layer and dragged the copy over the outline layer:


I then added a white mask to this copy (activate copy, right click and from menu choose “Add layer mask” and than “White”):


Now we have to make sure that we have black as the foreground color again.
(On the foreground-background selector click on small square):


Now I have painted the areas that should shine through with the black paint over the white mask (activate mask, choose “Brush” tool and paint over):

That’s it. I hope this will be helpful for you.


Boris, that is excellent. Thank you for posting this information!

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@s7habo thanks so much for this neat tutorial!

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