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IE & PNG

 
 
Headless
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      09-02-2003
Mark Parnell wrote:

>>>> IE6 displays certain (non transparent) PNG files wrong:
>>>> http://www.spartanicus.utvinternet.ie/ie_png.htm
>>>
>>> What exactly is the problem? It looks much the same in IE and
>>> Mozilla to me (except the white line between the images in Mozilla).

>>
>> Ah, maybe it's local to my machine. This is what I'm seeing:
>> http://www.spartanicus.utvinternet.ie/img/ie_png.png

>
>I understand the problem now. I do see the same as you - I assume that you
>are talking about the slight colour difference? The 2 images should be
>completely identical (in effect, look like one image)?


Yes.

>It seems that yes it is a bug in IE, but I can't see it ever being a
>problem. When are you going to have a gif and a png that are identical next
>to each other like that?


All the time, example: the image I used is used as a non tiled
background image, it's "padded out" to the right with a background
colour to get it to scale to width. The colour difference is impossible
to miss.

I do this all the time. Headers that use an image to get the nicer look
that you get due to anti aliasing, crop the image to make it as small as
possible, use it as a foreground image with a background colour to pad
it out so that it's scalable.


Headless

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Jason Summers
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      09-02-2003
Headless wrote:
> IE6 displays certain (non transparent) PNG files wrong:
> http://www.spartanicus.utvinternet.ie/ie_png.htm
>
> Anyone know what to avoid when creating png graphics that need to work
> in IE?


IE does gamma correction slightly wrong. (see
http://entropymine.com/jason/testbed/gamma/)

If you need the colors to match exactly, remove the gAMA chunk, or
replace it with an sRGB chunk.

 
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Headless
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      09-02-2003
Jason Summers wrote:

>> IE6 displays certain (non transparent) PNG files wrong:
>> http://www.spartanicus.utvinternet.ie/ie_png.htm
>>
>> Anyone know what to avoid when creating png graphics that need to work
>> in IE?

>
>IE does gamma correction slightly wrong. (see
>http://entropymine.com/jason/testbed/gamma/)


Thanks for that.

>If you need the colors to match exactly, remove the gAMA chunk, or
>replace it with an sRGB chunk.


Any tools you can recommend to do that? I've got a copy of png crunch
somewhere that can probably do it, but it's a bit to advanced for my
level, a tool with a GUI would suit me better.


Headless

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Jason Summers
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      09-02-2003
Headless wrote:
> Jason Summers wrote:
>
>>If you need the colors to match exactly, remove the gAMA chunk, or
>>replace it with an sRGB chunk.

>
> Any tools you can recommend to do that? I've got a copy of png crunch
> somewhere that can probably do it, but it's a bit to advanced for my
> level, a tool with a GUI would suit me better.


If you only have a few images, you could try using Tweakpng
(http://entropymine.com/jason/tweakpng/).

But pngcrush is probably easiest in the long run --
pngcrush -rem gama -srgb 1 in.png out.png

 
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Mark Parnell
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      09-02-2003
Headless wrote:
> Mark Parnell wrote:
>> It seems that yes it is a bug in IE, but I can't see it ever being a
>> problem. When are you going to have a gif and a png that are
>> identical next to each other like that?

>
> All the time, example: the image I used is used as a non tiled
> background image, it's "padded out" to the right with a background
> colour to get it to scale to width. The colour difference is
> impossible
> to miss.
>
> I do this all the time. Headers that use an image to get the nicer
> look
> that you get due to anti aliasing, crop the image to make it as small
> as possible, use it as a foreground image with a background colour to
> pad
> it out so that it's scalable.


Still not sure that I entirely understand what you are trying to do, but I
can see that there is obviously a legitimate use for it.

I see that someone else seems to have solved it for you, so best of luck.


--

Mark Parnell
http://www.clarkecomputers.com.au


 
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