Saturday, December 19, 2009

Red-Eye Reduction in GIMP and Gwenview

I have many photos on my computer and a good portion of them tend to be of people whose eyes become red on account of the camera flash (despite the orange light my camera emits as it's taking pictures).  In windows it's fairly easy to open up your red-eye affected photo and fix it up (practically in a few clicks of the mouse).  How easily can we accomplish the same task in Ubuntu? 

Today I'm going to load a cropped picture of two people with red-eye into two well-known programs in Ubuntu, GIMP and Gwenview.

The Offending Picture!

Red-Eye Reduction in the GIMP

I'll trust that you know how to open a picture in any program and cut to the specifics.  From here we have two ways to proceed: 

(1) If there are other red colours in your picture that you want to preserve:
  • Select one of the red-eyes in your picture with the ellipse-select tool
  • Click on the 'Filters' menu
  • Click on the 'Enhance' submenu
  • Click on 'Red-Eye Removal' (big surprise!)

Not so intuitive yet not too much to remember right?

Hope your fine motor control is effective here!

Next you will see the Red-Eye Removal configuration window where it will ask you to choose a red-eye threshold.  Above you can see that it gives you a preview of the eye that you're modifying.  The default threshold value seems to work without a problem.  So, press okay and move on to the other eyes in the picture.

The Result!

(2) If the only intensely red colours in your picture are in the eyes:
  • Don't select anything in the picture
  • Navigate to the 'Red-Eye Removal' filter as before
  • Press okay at the threshold that looks best (probably the default)

Easy for this picture, but beware of pictures with other reds in them!

Red-Eye Reduction in Gwenview

There's only one way of reducing red-eye in Gwenview and it is not very difficult:
  • Open up your photo in Gwenview
  • Under the 'Image Operations' pane, select 'Red Eye Reduction'
  • When your mouse cursor turns into a cross-hair, select the middle of any one of the red-eyes that you want to fix
  • A small circle will now appear on the spot where you clicked to 'de-red' the red-eye.  You can change its size using the dark grey panel that appears below the picture
  • When you're done, click apply and move on

Still need to have some good fine motor control skills here!

The Result!


The GIMP is a fantastic image manipulation program with so many features.  However, I find that Gwenview is simpler to use for this purpose.  My feeling is that many users wanting to edit photos will only want to do some of the simplest tasks: cropping, rotating, flipping and red-eye reduction, to name a few.  As I've demonstrated here with red-eye reduction, Gwenview is a very simple program to use.  To the user with such simple needs (I'm including myself here) I would recommend Gwenview.  However I certainly plan on keeping GIMP on my computer as there are times when I need something above and beyond the simple stuff.

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