Creating a 24-bit PNG with binary transparency?

[Leif K-Brooks]

Could someone please point me to a tool which can convert a 32-bit PNG
(24 bits of color, 8 bits of alpha channel) to a 24-bit PNG with binary
transparency? According to what I've read, this is supported by the
format and will work in IE, but I haven't been able to find any
information on how it's done.

 

[Dylan Parry]

Pondering the eternal question of "Hobnobs or Rich Tea?", Leif K-Brooks
finally proclaimed:

Could someone please point me to a tool which can convert a 32-bit PNG
(24 bits of color, 8 bits of alpha channel) to a 24-bit PNG with binary
transparency?

I thought you could only have 24-bit with alpha transparency, and 8-bit
with binary transparency? Photoshop certainly does allow me to use
24-bit PNG files with binary transparency.

 

[NullBock]

I'm not familiar with PNG transparency, but if it can be done, then the
Gimp can do it. Here's the website: http://gimp.org/.

The Gimp is a free, open-source, multi-platform image editor. The
learning curve is fairly high when first starting out, but it really is
a great tool.

Walter
----
Walter Gildersleeve
Freiburg, Germany

"We've heard that a million monkeys at a million keyboards could
produce the complete works of Shakespeare; now, thanks to the Internet,
we know that is not true." -- Robert Wilensky

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[Jim Higson]

I'm not familiar with PNG transparency, but if it can be done, then the
Gimp can do it. Here's the website: http://gimp.org/.

There's plenty of the PNG standard that the GIMP can't do properly. For a
start: Indexed images with trasparency, images with more than 32-bit
colour, gamma correction.

If you want an open-source editor that can do these things, try Krita.

 

[Toby Inkster]

There's plenty of the PNG standard that the GIMP can't do properly. For a
start: Indexed images with trasparency, images with more than 32-bit
colour, gamma correction.

GIMP can do indexed images with transparency -- just reduce the colour
depth of the image to 255 colours or less.

 

[Toby Inkster]

According to what I've read, this is supported by the format and will
work in IE

Just use the Image ALpha Loader thingy.

 

[Jim Higson]

GIMP can do indexed images with transparency -- just reduce the colour
depth of the image to 255 colours or less.

Not variable transparency. At least, you can edit it if you don't mind not
being able to see what you're editing!

see this bug report:
http://bugzilla.gnome.org/show_bug.cgi?id=86627

 

[Froggy]

Found the tool

Could someone please point me to a tool which can convert a 32-bit PNG (24 bits of color, 8 bits of alpha channel) to a 24-bit PNG with binary transparency?

Faced the same problem. If anyone is still interested, I've managed to find the tool - Pixelformer (it is basically an icon/bitmap editor). Just select RGB (24 bit) as the target format and export your image to PNG.