[Image-SIG] open, show, png, blank

[Chris Mitchell]

Hey Nelson,

Are you sure this image isn't actually a tiff (Every gel scanner I've ever
used outputs tiffs)?  Also, is it opening as an 8 bit image or a 16 bit?
 For a gel scan, it should be a 16 bit image, so you can consider forcing
the mode while opening it..

Chris

On Tue, Jan 31, 2012 at 1:38 PM, Nelson Tong <tongsnelson.ise at gmail.com>wrote:

> thanks for reply, Matthias,
>
> when I use "show()", the image appears to have an all-white
> background, nothing else is on it.  The size does indeed match the png
> size , I used the following to confirm:
>
>    x, y =  outIm.size
>    print "size of outImg: " + str(x)+" " + str(y);
>
> I tries to resave the png as a  png image with a different name using
> PIL and show() of the 2nd png image still appear to have all-white
> background with nothing on it.
>
> but If I open the images (both the 1st and the re-saved image ) with
> the command line command of "display", I can see the images via
> ImageMagick.
>
> Attached is example image which I am having problem with.  Can you
> reproduce the same problem I'm seeing with this image, possibly due to
> the png image being broken?
>
> -N.
>
>
> On 1/29/12, Matthias Bock <matthiasbock at users.sourceforge.net> wrote:
> > Am Freitag, den 27.01.2012, 11:11 -0500 schrieb Nelson Tong:
> >
> >>  outI = Image.open( fileOutPNGFile )
> >>  outI.show();
> >>
> >> The code run without error, but the image return via X-windows  on my
> >> linux machine is a blank image, without visible graphic on it.
> >
> > What color is this "blank": Grey? White?
> > Does the size match the PNG size?
> >
> >> I am 100% positive that the image of fileOutPNGFile is not corrupted
> >> because I am able to open it via the web-browser.
> >
> > Web browsers can open corrupted image files.
> >
> >> I tried the same code another to open  another png file which I use
> >> PIL to draw and save as png.   The code above is able to open and show
> >> this png file properly.
> >
> > Sounds to me, as if the first PNG was broken.
> >
> > Try this:
> >
> >  outI = Image.open( fileOutPNGFile )
> >  outI.show()
> >  outI.save('test.png')
> >  out2 = Image.open('test.png')
> >  out2.show()
> >
> >> why might this happen?
> >
> > If the code doesn't help solving the issue,
> > could you send the PNG to the list?
> >
> > Cheers, Matthias
> >
> >
>
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>
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