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Blur is confusing me.

Jul 6, 2013, 02:58 (This post was last modified: Jul 6, 2013 03:04 by MikePatterson.)
Post: #1
Blur is confusing me.
Hello, I've been aware of GIMP for years now and I've used it off and on throughout those years, but there is something that is really, really bothering me and I cannot find a solution online, so I'm hoping you folks can help me.

I've got a picture of a guy with this creepy smile and I thought it'd be funny to kind of make him look like the Joker with his creepy smile! So, this is what we got:

http://i.imgur.com/QryqIVi.png

Nothin fancy, spent less than 10 minutes making this effect because it's meant to just be quick and fun. However, I just thought, I'd try and make those red lips blur just a tiny bit, just a couple pixels, around the outer edges. I have the lips on a separate layer, and I am in RGB Mode. Well, the following two images illustrate what happens, I've put the radius of the Gaussian Blur filter to 10 pixels in order to exaggerate the effect for demonstrative purposes:

Blur Preview:
http://i.imgur.com/jdAOpt9.png

Blur Applied:
http://i.imgur.com/sIR1UH4.png

Obviously, this did not blur the image as indicated by the Preview. It seems like the Blur filter is confined to the edges of the layer itself. Is there some way to change this to make blurring occur on the edges of a layer? I am completely stumped by this one. Any help would be appreciated. Thanks for your time!

EDIT: I apologize if this is in the incorrect sub-forum. I wasn't sure exactly where this went.
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Jul 6, 2013, 07:56
Post: #2
RE: Blur is confusing me.
You might have alpha transparency locked on the layer you're trying to blur. Or an invisible selection? Can you draw at all on this layer outside of the lip region? If not, it's probably one of those.
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Jul 6, 2013, 08:55
Post: #3
RE: Blur is confusing me.
There is the above
my thoughts on things that go wrong.

Zooming in to the original image QryqIVi.png and the one where the blur should be sIR1UH4.png there is no difference.

Could be a lot of things, do you have an active selection somewhere on the target image? is the 'paste' above the target layer.

I would try again and see if you can get a 'floating' layer of the blurred lips. You can always put the floating layer to a regular layer for manipulation.

Something like this. separate blurred image copied and pasted as a new layer. http://i.imgur.com/Crhx0Hk.jpg

and the layer in position over the base image. http://i.imgur.com/KFwUKH3.jpg

Like ofnuts says above, the blur creeps onto the teeth, not difficult to fix.

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Jul 6, 2013, 22:01
Post: #4
RE: Blur is confusing me.
Thank you for your reply everyone! The lips are on a separate transparent layer (not pasted, already anchored on its own layer) and there is no selection whatsoever.

Quote: However, blurring something on a transparent layer extends the opaque parts with semi-transparent pixels, and in your case this will mean that the red will smear on the teeth.

^This is EXACTLY what I want to happen, and it is indeed very easy to just erase the resulting semi-transparent pixels from the teeth, if I could only get that far.

Quote:You might have alpha transparency locked on the layer you're trying to blur. Or an invisible selection? Can you draw at all on this layer outside of the lip region? If not, it's probably one of those.

Here is another pair of screenshots focusing on just the transparent layer of the lips, no selection. Where exactly do I go to find out if the alpha transparency is locked on the "lips" layer?
About to Blur:
http://i.imgur.com/ZFLRYKj.png
Blurred:
http://i.imgur.com/QhaQXBT.png

And there is a difference between the two images. Only the internal pixels are blurring.

Quote:I would try again and see if you can get a 'floating' layer of the blurred lips. You can always put the floating layer to a regular layer for manipulation.

Something like this. separate blurred image copied and pasted as a new layer. http://i.imgur.com/Crhx0Hk.jpg

and the layer in position over the base image. http://i.imgur.com/KFwUKH3.jpg

I'm not quite sure I understand, are you saying that I can only blur the edges of the lips after it's been pasted but before it's been anchored? Or are you suggesting I merge the layers, select the whole mouth, copy + paste the selection on a new layer, blur the layer, and then cut out the teeth? This latter idea could most definitely get the job done, it just seems like a whole lot of extra steps to achieve what the Gaussian Blur filter seems to suggest it's capable of doing on a transparent layer. Plus there would be extra pixels around the lips on the white skin that would be blurred that I wouldn't want to be blurred.

I feel like I'm missing something here. Undecided I'd like to clarify too, I really don't give a crap about this picture, I'm just using it as a vessel to address this larger concern with how the Gaussian Blur works in GIMP, it just doesn't seem to be consistent, or I'm misunderstanding something. Thanks again for the replies everyone, this is very helpful!
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Jul 7, 2013, 10:12 (This post was last modified: Jul 7, 2013 11:05 by rich2005.)
Post: #5
RE: Blur is confusing me.
I did it as a separate image and a small layer in an attempt to show the comparison between blur/no-blur.

From your original images I could see no difference between original and blurred when zoomed in. Made me think that the blurred layer was hidden in some way. Impossible to tell from your screenshots.

update Ok, these show the layers
Quote:About to Blur:
http://i.imgur.com/ZFLRYKj.png
Blurred:
http://i.imgur.com/QhaQXBT.png
And there is a difference between the two images. Only the internal pixels are blurring.

The gaussian blur preview looks fine and the blurred does not looked blurred at all to me but it is a small screenshot.



maybe experiment with a few less layers. It might prove working/not working.
Another more conventional go.

Duplicate layer, cut the lips out, blur (5 pix gaussian blur is plenty), the only concession I made was a selection to prevent the inside area blurring.
http://i.imgur.com/vylWs1J.jpg

Turn the bottom layer back on to check and the blur is there. (left the selection on but by this time it is not required.)
http://i.imgur.com/mrNwddA.jpg

On a small image as the example, other ways than Gaussian blur but that was not the question.

edit:
Sorry, got sidetracked for a while.

Going right back to Grues post, difficult to tell from your screenshots but make sure alpha-lock is off.

http://i.imgur.com/UDnM9Y5.jpg

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