please help - image changes color at the bottom of image

Discussion in 'General Discussion' started by Anonymous, Dec 13, 2010.

  1. Anonymous

    Anonymous Guest

    Hello there,

    Please help me figure out the problem. I have been using gimp to create designs that end up on all sorts of items like tshirts posters and buttons and so on. I have noticed an odd thing, and I don't know what the source of the error could be.

    If I have an image with lots of rich colors, patterns, and layers in Gimp, the color of the entire image seems to 'lighten' up progressively towards the bottom of the image.
    Even when the image is flattened into one layer, and turned upside. The bottom portion of the image will still be lighter than the top.

    This carries alway through to when image is printed onto a surface. A customer complained of big color variation between top of product and bottom of product. In this case it was an iphone case.

    Has anybody experienced this issue?

    I'm using Gimp 2.6 on Ubuntu Studio,
    9.1 Karma Koala
    CISNET pentium 4 (onboard graphics card)
    LCD monitor

    is it Gimp, Ubuntu OS, the graphics cards, the monitor settings?

    Please help and thanks for your time.
  2. Arzoroc

    Arzoroc Moderator Staff Member

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    If you view the finished image outside of GIMP, e.g. on IrfanView or some other picture viewer, does it still look the same?

    -Gimp: I have never heard of that problem in Gimp, you might try to reinstall it and see if it's the same.
    -Ubuntu: Well .. no. I don't think Ubuntu has got anything to do with this. If you want to be a 100% sure, send the files to a Windows/Mac computer and see whether it comes out the same way.
    -Graphics Card: As above, I don't think the graphics card would effect a data. It could show you something in a wrong way, but if you print the image, the GPU has no further influence and the picture therefor should be colored correctly. As I said above, try it on another Computer to get a 100% proof.
    -Monitor settings: Same here as on the GPU.

    Well, I've never had this problem, and I haven't heard about it either. Are you sure you didn't do any mistakes while making the XCF in GIMP? For example some layer with a transparent-to-white gradient on low opacity that gives the whole image this look?


    If you haven't got another computer and if you trust us well enough, you could upload the XCF file here and we'll have a look at it to see whether there's a mistake inside.


    P.S: Any grammar mistakes are intended. ::) ;)
  3. Maffe811

    Maffe811 Moderator Staff Member

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    Can you do your normal process and figure out when it goes wrong...
    Could you post an image so we can check if it works for us...
    And could we try making sumthing and send it to you for test print...
  4. Anonymous

    Anonymous Guest

    Thanks for your replies.

    I will look at the image in a windows OS and let you know.
    and fish out the best example of this issue in an image and post it.

    thanks again,
    writersblot
  5. Anonymous

    Anonymous Guest

    Here is the situation

    I looked at the image in a Window XP using built in image viewer application. The image color is slightly darker at the top, even when I turn the image upside down. But this doesn't happen to all images...just the COLOR images I create with GIMP.

    Okay...I think it's the LCD monitor. I just made two copies of this file...looked at them both side by side through image viewer. - then I moved one image further down the monitor screen, it gets just slightly lighter.

    But how can this affect the printing so dramatically? I don't do the printing myself. I just heard through client that there was a difference in color hue between top and bottom of image.

    Here is a temp link to the image - i've peared down the image and reduced the resolution and size.
    <a class="postlink" href="http://www.writersblot.com/gimp_test/TESTSM.png" onclick="window.open(this.href);return false;">http://www.writersblot.com/gimp_test/TESTSM.png</a>

    this image has one solid color #da2a5b at opacity of 29% over a solid white layer both at MODE: Normal, and other transparent layers.

    thanks so much for your time.

    regards,
    writesblot
  6. David Wood

    David Wood Active Member

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    It sounds like it's just the monitor, have you tried recalibrating it? As in regards to printing it shouldn't effect it at all, it's just the way the monitor sees the colors not the printer, I would try a test print and see if it looks different.
  7. Maffe811

    Maffe811 Moderator Staff Member

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    Nada problems on my dads screen, and thats a hyundai (no not a car, a lcd screen) something....
    so... i honestly dont know...
    i would fix the screen and take it from there...

    maybe there is some wierd connection between the screen and the printer... 8O
  8. Rod

    Rod Moderator Staff Member

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    Yeah that sounds like a monitor problem.
  9. Arzoroc

    Arzoroc Moderator Staff Member

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    But then the prints shouldn't be lighter at the bottom aswell.
    Try using another printer, just to be safe.


    By the way: Nice design :D
  10. Maffe811

    Maffe811 Moderator Staff Member

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    check list:
    1. fix/change screen
    2. try different printer
    3. say thank you to Arzoroc/baum for saying nice design
    4. say thank you to Maffe811 for saying nice design

    Nice design ;)
  11. Rod

    Rod Moderator Staff Member

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    Wow i just looked at the image you uploaded and it does fade at the bottom.Are you sure you are not using a gradient mask there?
  12. Maffe811

    Maffe811 Moderator Staff Member

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    [​IMG]
    Did this so you dont have to scroll up all the time!

    I see nada fading
  13. Arzoroc

    Arzoroc Moderator Staff Member

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    I loaded it in GIMP and picked one pink spot at the very bottom and one at the very top with the Color Select tool. They were exactly the same.
  14. Maffe811

    Maffe811 Moderator Staff Member

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    so only thing we have gotten out of this is that Rod's screen is off as well? :|
    Are we stuck ?
  15. Rod

    Rod Moderator Staff Member

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    nah its just an optical illusion.
  16. Maffe811

    Maffe811 Moderator Staff Member

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    Thoose are awsome ;D
  17. David Wood

    David Wood Active Member

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    Try opening the xcf on a different computer and see if it still has color differences. Other things to try: Print with a different printer. Try the same printer on a different computer. And try a different monitor.

    If it prints fine on another computer with the same printer then you might have a graphics card problem.
    If a different printer on the same computer has the same results: graphics card.

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