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Help with a horse

Oct 11, 2013, 00:06
Post: #1
Help with a horse
Very new to this program, basically teaching myself. I work in the horse industry, and am finding it very difficult to isolate horses from the background. I can get most of it fine, but the manes and tails are very difficult.

I've tried using layer masks, but the backgrounds are usually too busy to get the right contrast to isolate the hairs from the background. Any tips for hair from very bsy backgrounds?

I've included an example picture to demonstrate the kind of thing I'm struggling with.

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Oct 11, 2013, 09:16 (This post was last modified: Oct 11, 2013 09:22 by rich2005.)
Post: #2
RE: Help with a horse
Edit: re-reading your post, looks like you are doing as much as you can in the circumstances. All you can do is dive in with a small fuzzy brush and paint in/out those details in your layer mask.
Hair is the 'holy grail' of selections. Very-very problematic.

I do not think there is any quick-n-easy solution. After making your initial selection, dive straight into a quick mask and paint in/out the selection. 'Quick Mask' is at the bottom of the selection menu.

This example I used the foreground selection tool, a poor choice, a free-select or even magic scissors might have been better. screenshots:

The bulk cleans up easily with a quick mask but then you get into the fine detail and all you can do is carefully restore the fine detail. Your image is a decent size so you might get a reasonable result but do expect to restore those one pixel, semi-transparent hairs. (at least not easily) screenshots

You can do exactly the same with a layer mask, not a bad idea after the initial selection to convert the selection to a mask.

Some hints on work flow,
Save frequently to gimp xcf format. Save the selection(s) as you go, as a channel or as a path.
Be prepared to go in and out of a quick-mask many times to see what works and what does not.
Your friends in a quick mask are some of the key-board short-cuts.
'Shift-q' to toggle the quick mask on/off
'x' swaps foreground/background colours
The '] [' bracket keys to change the size of the brush.
click -> shift-click with the paint tool to paint in straight lines
and of course 'ctrl-z' to undo Wink

This is after 10 minutes, as you can see, lots & lots of work still to do.

Some references on this forum that might be useful.

** now answering questions**
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Oct 12, 2013, 08:12 (This post was last modified: Oct 12, 2013 08:36 by iForStyle007.)
Post: #3
RE: Help with a horse
Also, I have a couple of cool methods of extracting subjects with hair from the background, they're worth a try if you haven't gotten a satisfactory effect.
(the second tutorial below will may achieve the desired result with practice.)

Gimp has a selection editor where you can see & click to select (more on that here);

Threshold-filled mask in selection tutorial

EDIT: For method 2, I tried it with your picture, but since the jockey's pants are all white, you cant get an overall outline on both rider & horse. I upped the contrast to make a more solid outline. In threshold, you can try pulling the white triangle to the left some to get an overall selection. It might be a better idea to make the mask in sections for this pic.
(Threshold just the front half first, then fill it in and repeat the mask process for the back half of the horse & rider, tail might be another section.)
I'll post pictures soon of what I mean in my next post/reply.

For method 1, I'll post results with my next reply if it turns out well.
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Oct 12, 2013, 11:40
Post: #4
RE: Help with a horse
bloodstock, make sure you click the pictures for important details on how the edges will look.

Modified my method, by adding a laplace edge filter first. Because I'm kinda lazy to make the mask by sections as I mentioned earlier(might be cleaner but take MUCH longer XD
Filters > Edge-detect... > Edge...
- Then, under Algorithm:, pick "laplace" drag the slider all the way to the left if it isn't already, Click ok.
Then threshold, inverted selection, blur etc...see my fly away hair tutorial link.
My Result (with edge then threshold stages):
2. Then you wanna paint/clean the mask...

Painting your selection mask(Specific to your horse photo)
*This small part can be a bit time consuming, but it will look nice, if you start out a medium-large sized brush, it shouldn't take that long...

You can turn the layer on/off to see the original picture,
or turn the opacity to paint along the outline of the horse & rider.
----First, clean up the middle(horse & rider) with with white paint and
a hard edge brush. Start out with a medium-large size brush to cover the area quicker.

*(BRUSH SIZE) It will be faster to paint all the large areas first, then scale down the brush size for details, like in the
horses legs, ear and base of the horse's tail.
(don't paint over the white hairs; see pic)


Then, paint/clean up the background with a medium-large hard
edge brush.

Repeat "BRUSH SIZE" method too. For background
you can select large sections & "Edit > Fill with foreground []"(usually black).
Almost there...make sure you use smaller brushes for details, it will look like this on your first pass:


Now you can complete the mask tutorial(magic wand, etc, refer to my tutorial)

Here is my result:
(a new background with a light color or busy will be best for the hair, less noticeable artifacts/glowing edge)
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