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How does deleting pixels really work? - Adobe Photoshop Elements

When you outline an image and delete the background are you merely masking the background or are all the pixels lost? I always though that deleting an area removes it from the image file forever. When I make a JPEG from a PSD file, the Thumbnail shows up as the original image (the scanned JPEG that I used to make the PSD) with no editing. Clicking the image reveals what I truly want the viewer to see. Anyone know for sure? This is suddenly happening since about the end of July. Anyone know of a switch I may have turned ...

  1. #1

    Default How does deleting pixels really work?

    When you outline an image and delete the background are you merely masking the background or are all the pixels lost? I always though that deleting an area removes it from the image file forever. When I make a JPEG from a PSD file, the Thumbnail shows up as the original image (the scanned JPEG that I used to make the PSD) with no editing. Clicking the image reveals what I truly want the viewer to see. Anyone know for sure? This is suddenly happening since about the end of July. Anyone know of a switch I may have turned on or off by accident?
    ned block Guest

  2. #2

    Default Re: How does deleting pixels really work?

    Ned,

    If you are saying that the area you deleted wasn't replaced by any new data in the psd file, there would be a problem as jpg doesn't support transparency, tiff and psd do.
    Nancy S Guest

  3. #3

    Default Re: How does deleting pixels really work?

    If you are saying that you saved the image with a white background and that the background is white when you look at it in Photoshop but that it looks like the original picture background when you view it as a thumbnail, the thumbnail image probably hasnít updated to reflect the changes to the actual file. When the image is saved with a thumbnail (either with Photoshop or your OS) it creates a tiny little picture to go with it so that you donít have to wait for your system to read and then generate a thumbnail on the fly every time you open a folder with the file in it (it could become incredibly time consuming if it did generate them on the fly with larger files). It isnít really anything to worry about.
    E. Segen Guest

  4. #4

    Default Re: How does deleting pixels really work?

    Ned,

    To put things in another way, all images are nothing but pixels with each pixel having ONE color of a potential 16,777,216. But when working in Elements (or other progressive raster programs) you can eleminate the color from pixels and you'll "see" a "transparent" background. This would make you "think" that those pixels aren't there, but unless you have CROPPED the image (cut down the size of the "canvas", those pixels are still there. A "blank" canvas is nothing more than white pixels (the assumed color of print paper). Thus a blank image file and a full RGB color image on the same sized "canvas" will have exactly the same byte size (3bytes per pixel for raw image size ... not counting the raster format type size unless they are the same and not compressed. So when you make a transparency all you are actually doing is replacing the color of the pixel (for printing) with white, and white won't print as there is NO white ink (RGB), it uses the color of paper for white.

    Bob
    BobHill Guest

  5. #5

    Default Re: How does deleting pixels really work?

    Thanks to all for your replies. I am very lo-tech and this is all new to me. What I do is, working on Layer 0, I Lasso an area---hit Delete--and replace the area with a checkerboard. Eventually that leaves an image of my sculpture surrounded by the checkerboard. Opacity on the Layer is 100%. I then add a gradient on Layer 1 and the PSD image becomes the sculpture set against the gradient background. What I'm hearing from you is that I am just masking the background that I want to get rid of and the thumbnail retains the original jpeg image somewhat grayed out. So, on the OPEN pop-up I have a Thumbnail on the list that is wrong, but the selection image at the bottom of the screen is correct. Clicking on the Thumbnail in the Elements file list or any file list, produces an image the same as the PSD file. Saving the PSD file as a JPG flattens the layers so there's no problem with JPG handling a transparent layer??? I understand that there's no problem in all this except (1) it makes it difficult to select images from a thumbnail list if they don't represent the actual file and (2)when I send a CD of the art to a client, the Thumbnail on the CD is the original image with the unwanted background. Again, if they click, they get the desired image, but this is an important matter of presentation. The other very sticky point is that this just started happening in August and I can go back to other images I manipulated prior to that time and the PSDs copy to JPGs just fine. Yes, I'm using the same camera. Yes, I DO hear the theme music from Outer Limits playing in the background.
    ned block Guest

  6. #6

    Default Re: How does deleting pixels really work?

    Also, what OS are you using? Iíve had the folder thumbnails in both Mac OS 9x and Windows XP fail to update correctly.
    E. Segen Guest

  7. #7

    Default Re: How does deleting pixels really work?

    Ned, what happens when you give the edited image a new name? That's
    probably a good practice anyway, as you'd generally not want to replace your
    original but rather supplement it with an edited version. The newly-named
    image should generate a new thumbnail within XP, I would presume...

    Chuck


    Chuck Snyder Guest

  8. #8

    Default Re: How does deleting pixels really work?

    Chuck---Done that---actually, always do that. The code people are too smart to let me get away with that little trick. I guess tomorrow I hit the phones. Thanks.
    ned block Guest

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