transparent PNG
Steffen Glückselig
I have an finished PNG of which I would like the background to be
transparent.
Like often discribed here I add an alpha-channel, do the selection and
erase the background.
The background then gets this chess-board-like pattern ;-)
Now after saving, closing and reloading that pattern has vanished.
Also testing with my browser (Opera 6.02 which supports transparent
PNG, at least http://kimihia.org.nz/how/gimpalpha/ works for me...)
shows that the background is not transparent.
May I be doing something wrong when saving? What do I have to look
for?
Thanks in advance...
Steffen
Jim Lokken
I believe when you save as png, a dialog box comes up and you have to
uncheck the "save background color" item. This is what worked for me.
Steffen Glückselig
wrote:
Hello,
>I believe when you save as png, a dialog box comes up and you have to
>uncheck the "save background color" item. This is what worked for me.
Thanks for your answer!
I tried ticking everything except "save background color" and still
the next time I open the PNG the background is not shown with
transparent-pattern.
BTW I am using version 1.2.0 on Windows95...
Steffen
Branko Collin
09:15:01 -0600:
>Steffen Glückselig wrote:
>> I have an finished PNG of which I would like the background to be
>> transparent.
>> Like often discribed here I add an alpha-channel, do the selection and
>> erase the background.
>> The background then gets this chess-board-like pattern ;-)
>> Now after saving, closing and reloading that pattern has vanished.
>> Also testing with my browser (Opera 6.02 which supports transparent
>> PNG, at least http://kimihia.org.nz/how/gimpalpha/ works for me...)
>> shows that the background is not transparent.
>> May I be doing something wrong when saving? What do I have to look
>> for?
The only thing I can think of is that you have multiple layers, with
an invisible (opaque?) background layer. PNG does not support layers
as such, so the GIMP will have to flatten the image before saving. It
will then add a BG-coloured background to your image. You should get
a warning message to that effect.
To avoid getting a solid background, you should make sure the
background layer is transparent. In the layers dialog, the background
layer is usually called Background (unless you changed its name).
Hmmm... I've tested it, but no matter what I try, I cannot get rid of
the transparency.
BTW, the chess like pattern is not saved, it is only shown in the GIMP
so that you can see the transparency.
>I believe when you save as png, a dialog box comes up and you have to
>uncheck the "save background color" item. This is what worked for me.
That's only important for indexed transparency in web browsers, it
should not influence the reloading in the GIMP.
--
branko collin
Volk van San Theodoros, ik heb U begrepen.
Steffen Glückselig
wrote:
Hello Jim,
>The only thing I can think of is that you have multiple layers, with
>an invisible (opaque?) background layer. PNG does not support layers
>as such, so the GIMP will have to flatten the image before saving. It
>will then add a BG-coloured background to your image. You should get
>a warning message to that effect.
In the layers-dialogue I have just one: "background", which shows the
complete picture.
I do have one channel which is "indexed".
>To avoid getting a solid background, you should make sure the
>background layer is transparent. In the layers dialog, the background
>layer is usually called Background (unless you changed its name).
>
>Hmmm... I've tested it, but no matter what I try, I cannot get rid of
>the transparency.
In the layers-dialogue the "keep transparency" (I use the
german-version so I am "translating" here ;-)) ticker is not ticked.
The slider below is positioned at 100.0.
I played around with those settings a bit but couldn't come up with
something working...
>BTW, the chess like pattern is not saved, it is only shown in the GIMP
>so that you can see the transparency.
Yes ;-) I guessed that pattern would show up in Gimp after re-loading
such a picture indicating the background was set to transparent, or am
I mistaken here?
greets
Steffen
Branko Collin
17:42:25 +0100:
>>BTW, the chess like pattern is not saved, it is only shown in the GIMP
>>so that you can see the transparency.
>Yes ;-) I guessed that pattern would show up in Gimp after re-loading
>such a picture indicating the background was set to transparent, or am
>I mistaken here?
No, your correct.
I have no idea what causes your problems.
Can you save transparent GIFs and TIFFs this way?
Jim Lokken
When I first tried saving a partially transpaarent PNG, I ended up with
the same problem that it filled in a white background. I changed two
things, one was the checked button, the second was to delete the white
background layer that was not visible (no "eye" in the layers) in the
first place. Maybe that was what actually worked and I gave credit to
the wrong step. I was under the assumption that only the current layer
would get saved if I used any format other than XCF. It didn't really
seem that way to me for PNG, and as an added bonus there, it seemed to
show a layer that wasn't to be shown and saved it like it was flattened,
although the layers dialog did not show the flattened effect. Maybe it
seemed that way because my background was white and PNG maybe selects
white as it's default backround color. I don't know, as I didn't try
anything more once I got it to work.
Jim
Raphael Quinet
> When I first tried saving a partially transpaarent PNG, I ended up with
> the same problem that it filled in a white background. I changed two
> things, one was the checked button, the second was to delete the white
> background layer that was not visible (no "eye" in the layers) in the
> first place. Maybe that was what actually worked and I gave credit to
> the wrong step. I was under the assumption that only the current layer
> would get saved if I used any format other than XCF. It didn't really
> seem that way to me for PNG, and as an added bonus there, it seemed to
> show a layer that wasn't to be shown and saved it like it was flattened,
> although the layers dialog did not show the flattened effect. Maybe it
> seemed that way because my background was white and PNG maybe selects
> white as it's default backround color. I don't know, as I didn't try
> anything more once I got it to work.
I am not sure about what is wrong in your case, but I highly recommend
that you upgrade to GIMP 1.2.3. This release fixes an important bug:
http://bugzilla.gnome.org/show_bug.cgi?id=51114
This bug could cause the transparency or layer offset to be lost in
some cases when saving an image as PNG (or TIFF or other formats).
The description of the bug is a bit long, but maybe you will find that
your problem is covered by this bug report or the related ones (follow
the links in that page). If this is the case, then upgrading to 1.2.3
would solve your problem.
-Raphael
Steffen Glückselig
wrote:
Hello Raphael,
>I am not sure about what is wrong in your case, but I highly recommend
>that you upgrade to GIMP 1.2.3. This release fixes an important bug:
> http://bugzilla.gnome.org/show_bug.cgi?id=51114
Is this version available for windows-systems? I couldn't find it on
wingimp.org, though...
greets
Steffen
Steffen Glückselig
<ste...@gungfu.de> wrote:
[gimp version 1.2.3]
>Is this version available for windows-systems? I couldn't find it on
>wingimp.org, though...
The installer is available. Since gimp.org is not available currently
it took time to find this out. Sorry for asking unnecessarily!
greets
Steffen
Branko Collin
18:36:15 +0100:
wingimp.org is the domain of Matt Caughron, who sells GIMP
distributions. He should start selling GIMP 1.2.3 for Windows in a
while now.
The _only_ official GIMP web site is <http://www.gimp.org>.
To obtain GIMP 1.2.3., go to <http://www2.arnes.si/~sopjsimo/gimp/>.