Re: [Gimp-user] Image diffenernt after saving

[Richard <strata_ranger hotmail com>]

> Date: Mon, 23 May 2016 08:08:19 +0200
> From: forums gimpusers com
> To: gimp-user-list gnome org
> CC: notifications gimpusers com
> Subject: [Gimp-user] Image diffenernt after saving
>
> I forgot to say that, but it is not really tansparent, Privot takes the bottom
> right (or left, I'm not sure) pixel and makes all of this color tansparent. So
> in GIMP 2 it is white, and in Privot tansparent, with the bug as shown in the
> image. But yes I will try that with the eraser tool, thanks for your answer.

Okay.  Then the problem is that your background color isn't a solid white but actually several (subtly) 
different shades, and even a +/-1 difference in a pixel's RGB values may dictate whether Pivot treats it as 
opaque or transparent.

How to fix it remains largely the same in concept, but the execution will be slightly different.  And there 
are several ways, depending on exactly what you want.

For example, take the Paintbrush (or Pencil tool) and pick a fairly hard-edged brush shape, set GIMP's 
foreground color to your desired background color, then start painting around the background spaces of your 
image.  This will ensure that the background really IS a single solid RGB value and not a mix of hues or 
tints.

This can also be somewhat automated:

- Switch to the Fuzzy Select tool and on its tool options, specify a small threshold value (say, 8-16 range) 
and disable the antialiasing and feathering options.
- Click somewhere in your desired background area.  This will highlight all contiguous regions whose color is 
within the threshold of the pixel you clicked.
- FIll the area with a solid color (e.g. Edit > Fill with FG/BG color, or Paint bucket tool with "fill whole 
selection" option set).

But automatic tools never yield a truly perfect solution -- you'll only get that from manual effort.

By the way, since you mentioned how Pivot uses a 'chroma key' system, I'd recommend picking a color that is 
obviously not a normal part of the image (e.g. a pure RGB primary or secondary) and painting the image's 
background with THAT.  This will eliminate any ambiguity about which pixels are intended to be opaque or 
transparent in Pivot, because only your key color will be rendered transparent.

-- Stratadrake
strata_ranger hotmail com
--------------------
Numbers may not lie, but neither do they tell the whole truth.