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Transparency issues with PNG...

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Dante -  
Luke1 Posted messages 18751 Registration date   Status Contributor Last intervention   -
Hello, Good evening
I have a problem with achieving transparency using GIMP...
Transparency works with PNG format and not with JPEG,
I have downloaded various software to convert JPEG files to PNG...
But when I try to apply transparency,
it turns white instead of showing a checkered pattern that indicates transparency...
What should I do???

Because it works when the file is initially in PNG, but if it's a JPEG converted to PNG, it doesn't work!
There you go.
Thanks for your responses, see you later
Configuration: Windows XP Firefox 3.0.6 GIMP

3 answers

  1.
    Luke1 Posted messages 18751 Registration date   Status Contributor Last intervention   5 436
     
    Good evening,

    Yes, it's normal, simply saving your transparency as JPEG instead of PNG will automatically give you white, and even if you try to convert JPEG to PNG, you won't get your transparency back. If you want to keep transparency with GIMP or any software that handles PNG transparency, you need to save it this way: my_image.png, but if you do my_image.jpeg it's gone, the transparency becomes white and it's irreversible, you will never get back what you had. In PNG: http://img37.imageshack.us/img37/8263/impactcopie.png and in JPEG: http://img37.imageshack.us/img37/5040/impactcopiel.jpg. Impossible to revert JPEG to PNG...
    You can use the first bullet impact (png) if you need it, it's transparent but not the second one... ;-)

    Luke.

    --
    The price of a program is inversely proportional to its ergonomics.
    3
  2. Anonymous user
     
    Hello Dante

    Hello Luke,

    I don't know if Gimp can do it or not, or Photoshop Elements,

    But with my version of Photoshop (version 8) and also with Preview on Mac, I can go back, and therefore start from a jpeg to make a png with transparency.

    In Photoshop, I delete the desired color areas (you can see the checkerboard that proves the transparency), then I save it as a PNG. You need to be in indexed color mode at that moment.

    For example: I published this image recently for someone else..
    http://www.zimagez.com/zimage/image3-cropped0.php

    I just took it again to make a PNG with transparency
    http://www.zimagez.com/zimage/test3104.php

    Best regards

    PS: with Preview on Mac, the procedure is different and very quick.
    --
    Sanspseudo - Francis
    iMac-G5 - 2ghz - 2Go - Mac OS 10.5.7
    0
  3. Luke1 Posted messages 18751 Registration date   Status Contributor Last intervention   5 436
     
    Good evening Sanspseudo,

    Well yes, in this way it is always possible, provided you cut out the white or erase it, we regain the transparency and just need to re-save as png, but I have the feeling that Dante is just considering converting jpeg to png with GIMP and in that case..... :-/

    Have a good end of the evening.

    Best regards.

    Luke.

    --
    The price of a program is inversely proportional to its usability.
    0