[Gimp-user] drop out background tutorial

2009-09-15 Thread Bob Meetin
Subject says it all.  I have a large assortment of product pictures 
which I need to give uniform backgrounds, preferably white.  Can someone 
point me to a tutorial that discusses how?  You can see a representative 
sample image at: http://www.dottedi.biz/images/diagnostics/DSC_4355.JPG. 
They can probably live with the shadows if I can lose the bulk of the 
background.

Thx, Bob

___
Gimp-user mailing list
Gimp-user@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user


Re: [Gimp-user] drop out background tutorial

2009-09-15 Thread Paul Hartman
On Tue, Sep 15, 2009 at 4:32 PM, Bob Meetin b...@dottedi.biz wrote:
 Subject says it all.  I have a large assortment of product pictures
 which I need to give uniform backgrounds, preferably white.  Can someone
 point me to a tutorial that discusses how?  You can see a representative
 sample image at: http://www.dottedi.biz/images/diagnostics/DSC_4355.JPG.
 They can probably live with the shadows if I can lose the bulk of the
 background.

The documentation :)

http://docs.gimp.org/en/gimp-tool-foreground-select.html

(not sure which version of Gimp it was written for or which version
you're using)
___
Gimp-user mailing list
Gimp-user@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user


Re: [Gimp-user] drop out background tutorial

2009-09-15 Thread Bob Meetin

Paul Hartman wrote:

On Tue, Sep 15, 2009 at 4:32 PM, Bob Meetin b...@dottedi.biz wrote:
  

Subject says it all.  I have a large assortment of product pictures
which I need to give uniform backgrounds, preferably white.  Can someone
point me to a tutorial that discusses how?  You can see a representative
sample image at: http://www.dottedi.biz/images/diagnostics/DSC_4355.JPG.
They can probably live with the shadows if I can lose the bulk of the
background.



The documentation :)

http://docs.gimp.org/en/gimp-tool-foreground-select.html

(not sure which version of Gimp it was written for or which version
you're using)
  
I have seen this before but never used it for a project.  Okay now I 
played with it for a few minutes.  There must be some trick/finesse to 
getting it to zero in on the subject, really on the subject's edges.  By 
following the instructions in* Figure 13.26 *and keep redrawing the line 
the border gets pretty mixed up in the shadow areas especially.  Maybe 
it's my inexperience, but I can actually get a smoother edged selection 
by using the Paths tool.  2.4.5 on Ubuntu - Bob
___
Gimp-user mailing list
Gimp-user@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user


Re: [Gimp-user] drop out background tutorial

2009-09-15 Thread Chris Mohler
On Tue, Sep 15, 2009 at 6:04 PM, Bob Meetin b...@dottedi.biz wrote:
 I have seen this before but never used it for a project.  Okay now I played
 with it for a few minutes.  There must be some trick/finesse to getting it
 to zero in on the subject, really on the subject's edges.  By following the
 instructions in Figure 13.26 and keep redrawing the line the border gets
 pretty mixed up in the shadow areas especially.  Maybe it's my inexperience,
 but I can actually get a smoother edged selection by using the Paths tool.

Paths tool is a good choice.

Here's a poor man's isolation method:
http://yfrog.com/b5dsc4355retouchj

This is just a levels adjustment (Colors-Levels): auto, then pull
the highlight slider in toward the center.  As you can see it's not
perfect, but if the BG is the same on all the pics, it might be a
time-saver since a little erasing here and there should be enough to
clean up afterwards.

HTH,
Chris
___
Gimp-user mailing list
Gimp-user@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user


Re: [Gimp-user] drop out background tutorial

2009-09-15 Thread David Gowers
On Wed, Sep 16, 2009 at 7:02 AM, Bob Meetin b...@dottedi.biz wrote:
 Subject says it all.  I have a large assortment of product pictures
 which I need to give uniform backgrounds, preferably white.  Can someone
 point me to a tutorial that discusses how?  You can see a representative
 sample image at: http://www.dottedi.biz/images/diagnostics/DSC_4355.JPG.
 They can probably live with the shadows if I can lose the bulk of the
 background.

 Thx, Bob

For this kind of thing, there is the name 'greenscreening', in which a
matte, contrasting color is used as a background for an object,
allowing the object to be easily separated from the background.

In that case, Foreground-select is ideal.
However, you basically have the opposite: A photo of a bluish-gray
object on a bluish-gray background. Naturally this is very hard to
separate automatically!
So for such pathological cases, paths is probably a better choice.

Smoothness is not a big deal (in fact the selection created by
foreground-select is entirely binary, no smoothing involved)... this
is because you can convert the selection to path and then that path
back to selection if you want it smoother.

If I needed to handle your example in the way you want, I would:
* use foreground-select to get a rough approximation (make sure that
there are no 'holes' by marking areas as foreground as needed)
* enter QuickMask mode (click the icon to the left of the scrollbar)
* select paintbrush with an appropriate brush and black color, paint
away the wrongly selected parts
* exit QuickMask mode (click the icon to the left of the scrollbar)
* Select-To Path
* Tweak the path if needed
* right click on the path in the Paths dialog - 'Path to Selection'

If your example wasn't pathological (ie if it had a good contrasting
background), I would just use foreground select, convert to a path,
tweak the path, and convert it back to a selection.

Afterwards in either case, I'd probably just Select-Invert and fill
with white (like this: http://i26.tinypic.com/bdpjm0.jpg )
___
Gimp-user mailing list
Gimp-user@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user