Re: [Gimp-user] Having trouble creating transparent background

[Steve Kinney <admin pilobilus net>]

On 02/02/2017 01:17 PM, Accordeoniste wrote:
> Hello Steve,
>
> Thanks for your suggestions. I did as you suggested and I'm pleased with the
> result. It was a painstaking process, though. I had to enlarge the image,
> sometimes to 400%, to be able to see it clearly enough to make the necessary
> changes. Editing the background was delicate work as I had to be careful not to
> make the photo transparent. There was much trial and error involved. There's
> still a very slight bit of jaggedness on the perimeter of the photo, but
> fortunately it's not so noticeable at magnifications less than 50%. Also,
> fortunately, any imperfections in the exported image (including those I didn't
> eliminate in the photo itself that I considered minor, although I may go back
> and do that later) should become more insignificant once I place my photo on the
> background photo I mentioned.

Yay!

Here's something that might be interesting to try:  Make a copy of your
masked layer, turn off visibility of the original layer (click the
eyeball icon in the Layers dialog), and click the mask on the visible
copy to make it the active selection.  Then, blur the mask and check the
visible result.  A few pixels of blurring might give a more realistic
blending with the background.  As always, Control+z (undo) is your
friend, try a couple of different values - maybe just 2 or 3 pixels,
maybe more - and see what happens.

> Perhaps you can help me with this too. What are your thoughts about blurring the
> background image after I place my photo over it? Will it enhance or detract from
> the combined image? I ask this because I based my photo theme on a Wordpress
> template when I took my photo, and the template photo features a model against a
> blurred background of office buildings. The model stands out distinctly in the
> photo, and it looks very professional.

Ah yes - this technique is often used to make a foreground object stand
out in a picture.  It simulates a sharp focus on the foreground object
with a relatively flat depth of field.  Don't overdo the blur if you
want a "realistic" looking result though.

Another way to make the foreground stand out is to slightly reduce the
saturation and contrast of the background, again careful not to overdo
it unless you want the finished product to look manipulated, vs. just a
little extra eye-catching.

Yet another method - a favorite of mine - is a vignette.  Put a new
layer over your background, give it a layer mask, and use the Ellipse
Selection tool to draw an ellipse around the foreground object, with its
edges maybe halfway or so between the outline of the foreground object
and the edges of the image as a whole.  Do Select > Feather and pick a
big value - maybe about half the distance from the edge of the ellipse
to the foreground object.  This will, in effect, "blur" your selection.
Then drag and drop black from your color selector to the image canvas
with the mask selected in the Layers dialog.  This will make your new
layer transparent in the area including your foreground image.  Then
select the image component of the layer in the Layers dialog, drag and
drop black to the image canvas, and viola:  The result is your
foreground object visible in an oval surrounded by black.  Finally, in
the Layers dialog, use the transparency slider to turn the visibility of
your new layer WAY down.  Adjust until the effect of the vignette layer
on the visible image is barely noticeable.  Viola, all eyes on the
foreground object.

Some combination of the above methods should give you results you like.
Again, don't overdo it unless you want a "bold" a.k.a. unnatural looking
result.  The beauty part:  You can come back later and, if you don't
like the result after a break from looking at it, open up the XCF file
and make any changes needed - you still have all the original parts of
the un-messed-with image available to play with.

:o)