Lowering Image Quality

Forums Forums Get Technical Farktography tech talk Lowering Image Quality

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  • #1669
    PandyFarmer
    Participant

    My camera takes really really big pictures (and I like it that way). However, sometimes (like with foliage and stuff) the image size is way bigger, and I can’t post the size I like to the Farktography threads. In Photoshop CS3 when you Save As, after choosing the file name and format, there’s a “quality” option. Even on the lowest setting, the file is too large.

    I know there has to be other ways to change this, but I don’t know them. Do any of you?

    #23940
    SilverStag
    Participant

    First off, you want to resize your image in Photoshop (or the image editing software of your choice) to no more than 640 pixels wide for Farktography, since if you send a larger size it will automatically be resized down anyway. Think of it like this (and not factoring in jpeg compression) :

    A camera produces a 3000×2000 image. That’s 6 million pixels(for argument’s sake- let’s not get pedantic here)

    Resizing that image to the 640×426 brings it down to about 272,000 pixels.

    Jpeg compression brings the size down farther. Fark has an (approximately) 200K limit on inline images, to help keep threads loading at a reasonable speed. The quality setting you mention, will, by reducing the spatial frequencies (essentially tossing fine detail) reduces the file size even farther. For Farktography, I usually set it at 5 or so, since the monitor doesn’t show fine detail at hose sizes anyway.

    Also, over-sharpening a photo can increase file size dramatically- try going a tiny bit softer- at smaller sizes it’s less noticeable. The name of the game is to reduce the amount of high-frequency signal in the photo (i.e. fine complicated detail) so as to let the compression engine work better.

    One trick is to apply selective sharpening- make a duplicate layer of your photo – sharpen that, and then use a layer mask to hide high-frequency areas where sharpening isn’t all that important (background foliage for example).

    #23941
    nobigdeal
    Participant

    Photoshop editor:

    Top left hand side click Image: from the drop down menu click :resize click: image size, change image size to 640 pixels in the width box that pops up. Make sure you have the box checked that says constrain proportions. Hit ok and save as you normally would using the quality slider to get under 200kb (you should be pretty close). This will make the photo Fark appropriate sized. You can save a larger version to upload to Flickr also and put a link to that in your post.

    #23942
    clouddancer
    Participant

    I’m not sure how Flickr is, but in Photobucket, you can resize pictures. I usually upload my big picture into Photobucket and then have it save a copy to resize and I post the small one that links to the big one. If Flickr has that option, I’d suggest that. I don’t actually have Photoshop on my ‘puter, but asking Hubby to do mine every week gets annoying (and he is annoyed by it) so I just use that. I believe that Microsoft Picture Studios has an option too, if you have that.

    P.S. I think it’s okay to walk from the camera. I tried to get my son to run with me and he stopped at the hose instead and tried to soak me.

    #23943
    Curious
    Participant

    whatever you do to resize the image ALWAYS do it to a copy.

    yeah you all know that but even i (who almost always makes a copy to edit) will sometimes get in a hurry. with photoshop when you do the resize “save” function it will allow you to make a new file name. doing that in conjunction with working from a copy will make it fairly safe that you don’t change your original.

    also don’t use “save as” use the “save for web” which has a built in resize option. do the resize first at 640 with the box checked that says constrain proportions. then the quality part. it should show you the kb for each setting. while 200kb is fark’s upper limit below 100 is better for load times and usually won’t make much difference in your vote totals. this is after all a 640 pixel wide photo on fark not an entry in a fine arts show.

    #23944
    3Horn
    Participant

    Just keep in mind that “save for web” will strip EXIF data, so if that’s important for you, stick with “save as”.

    #23945
    GregScott
    Participant

    With regard to avoiding editing your original, this is one of the reasons I shoot raw whenever possible. Since you don’t edit a raw image, it functions as your original, unedited archive image. It takes more space, but the other advantages make it worth the effort. It can slow down the burst rate of your camera, but that’s rarely an issue for me.

    #23946
    Choc-Ful-A
    Participant

    With regard to avoiding editing your original, this is one of the reasons I shoot raw whenever possible. Since you don’t edit a raw image, it functions as your original, unedited archive image. It takes more space, but the other advantages make it worth the effort. It can slow down the burst rate of your camera, but that’s rarely an issue for me.

    I hadn’t thought of that (the raw file as the original I never edit) but in practice that’s exactly what I end up doing. I batch convert all the raw files to PNG and only go back to the raw files if I screw up the PNG somehow.

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