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Resizing a photo to a different ratio

Discussion in 'General GIMP help' started by Etz-Ron, Aug 7, 2015.

  1. Etz-Ron

    Etz-Ron New Member

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    Since I made a camera switch, the resizing of my photos got complicated. old camera took photos at 640 x 480, new camera at 1024 x 684. I need to get the old photos into the new ratio. I have figured out that the new ratio is equal to 640 x 456 EXCEPT when the photo uses all the image space, then it cuts off the photo( not good!). How can I create a new canvas and drop the old, perhaps made smaller (how to do?) into the new canvas? Any ideas? Please don't ask me to change setting on camera as I must use old photos, since I no longer have access to items photographed, for website, and new ratio site wide is 1024 x 684.
     
  2. rich2005

    rich2005 New Member

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    Ancient image sizes. 640x480 was know as VGA. Switch to a new camera? Sounds as if it might be webcam sizes.

    To maintain the aspect ratio of the old image and preserve all of the image, in video it is known as pillaring. Putting 'bars' down each side to increase the width.

    In Gimp you do this in stages.

    1. Resize your 640x480 image to ??? x 684 (??? comes out at 912 pix).
    Image menu -> Scale Image
    Keep the link between width and height joined put in the height and the width is set automatically.
    [​IMG]

    2. Next resize the canvas.
    Image Menu -> Canvas Size.
    This time the link between width and height is broken so enter the new width 1024.
    Click on the Center button and set Layers to All Layers
    [​IMG]

    3. That gets you a correct size image 1024x684 with transparent edges. If needed remove the transaprency.
    Layer menu -> Transparency -> Remove Alpha Channel
    The sides reduce to whatever background colour is set. In this case black.
    [​IMG]
     
  3. Etz-Ron

    Etz-Ron New Member

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    Hi Rich2005,

    Thanks you so much for your easy to follow instructions! I got it to work first time! Most important, though is knowing the terms so able to communicate accurately. Never heard of pillaring.

    So I am going to ask for more instruction that has been alluding me:

    I have some photos in portrait (configuration) that need to be changed to landscape. Sometimes said photos are in portrait form using the old 640 x 480 old ratio. So first, how do I get those old photos into landscape (1024 x 684)? What step(s) do I add to above instruction? ( I do not know how to change photos from portrait to landscape for starters- I tried to add wings on the sides (but could not get the wings to "stick") with the idea to resize the whole thing afterwords- there has to be an easier way)

    As you can guess I am a newbie- not quite understanding the "why" it works, but able to follow instruction.
     
  4. rich2005

    rich2005 New Member

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    You can rotate an image from landscape to portrait
    Image menu -> Transform -> rotate 90 (either clockwise or counter-clockwise to suit)
    [​IMG]

    Then it is exactly the same procedure,
    Scale the image, set height to 684, the width this time becomes 513 pixels
    Increase the canvas size to 1024 pix wide and center, use all layers as before. This time the 'pillars' become much wider. but this is the maximum size without losing part of the original image.
    [​IMG]

    edit: I have a feeling I miss-understood you. Are the images 'on their side'
    Whatever format, you can rotate as above.
     

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