Resize in NC or PSCS

Discussion in 'General Technical Discussion' started by jklofft, Jul 26, 2005.

  1. Which tool do you use for resizing? I've been using NC, but I see that many use PS. Does anyone know the pros/cons of each approach? Also what about FM's resize action?
     
  2. Ken-L

    Ken-L Guest

    I use Irfanview to resize after everything else.
     
  3. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    I resize in stages with Photoshop. First resize is to half the dimension, Bicubic Smoother. then I use Smart Sharpen to bring back the crispness, then a second resize with Bicubic or Bicubic Sharper if needed.

    Sometimes Bicubic Sharper is too aggressive, and sometimes it's needed. you just have to try and evaluate on a pic by pic basis.
     
  4. Hermie

    Hermie

    36
    Jul 23, 2005
    Saw these interesting statements by Thomas Knoll and Chris Cox (Adobe engineer) on Adobe forums:

    Thomas Knoll - 7:21am May 3, 05 PST (#4 of 10)

    "The size popup in ACR is just a convenience to the user. It uses about the same quality algorithms as resizing in Photoshop CS or CS2, and Photoshop can upsize to extreme sizes if you need to. (If you really want to control the resizing in ACR3 you can set the crop tool to crop to a specific pixel size, up to 10,000 pixels on each side).

    Also, with Photoshop CS and CS2, don't waste you time doing "10% steps". That actually results in worse quality in most cases."

    Link to original thread:
    http://www.adobeforums.com/cgi-bin/webx?14@553.0aSDehWNBul.24@.3bba34a3/0

    Chris Cox - 1:10pm May 19, 05 PST (#6 of 14)

    "In CS and CS2, you shouldn't need to do downsampling in steps.
    (we should have the full prefiltering done, and downsampling in steps will lead to artifacts)"

    Link to original thread:
    http://www.adobeforums.com/cgi-bin/webx?14@553.0aSDehWNBul.32@.3bba7e3b/0

    The point that Knoll and Cox are making is that stepwise resizing in PS CS and CS2 will not improve results compared to 1-step approach!
    Earlier versions of PS will benfit from stepwise resizing.

    Herman
     
  5. I use Fred Miranda's PI for resizing and like it a lot. It is simple and fast.
     
  6. Hermie

    Hermie

    36
    Jul 23, 2005
    Do you mean SI (Stair Interpolation) ?
    See also my note above. Stepped resizing (that's what SI does) will not lead to better results with CS/CS2. Older versions of PS is a different story.

    Herman
     
  7. I use WP Pro for downsizing and SI for upsizing.
     
  8. What's WP Pro?
     
  9. Hermie

    Hermie

    36
    Jul 23, 2005
  10. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    Thanks for the info. I will confirm this with my next project.
     
  11. Hermie

    Hermie

    36
    Jul 23, 2005
    Actually, ACR's upsizing is really very good. Some time ago I did a comparison between ACR and specialized tools like "Genuine Fractals PrintPro" and "PhotoZoom Pro".

    The example below was shot with a D2H. At the bottom you'll see crops of this image that were upsized at ACR's maximum resolution = +200% (Normal size D2H 2464 x 1632, upsized to 5120 x 3391 = 17.4 MP).

    [​IMG]

    To judge the crops, open up this image in Photoshop and zoom in to something like 400%.

    "Genuine Fractals PrintPro" and "PhotoZoom Pro" address extreme upsizing (+600/700%) and my test does not cover anything above 200%.

    In Photoshop CS/CS2 it should be a 1-step approach. If the maximum resolution of ACR is not sufficient, use the default raw resolution for your camera and do the upsizing in Photoshop.

    Herman
     
  12. Hermie

    Hermie

    36
    Jul 23, 2005
    ... and a test comparing upsizing with 600% !

    [​IMG]

    Genuine Fractals: Has no sharpening control, but obviously sharpens
    PhotoZoom: Sharpening turned off

    Herman
     
  13. Hermie

    Hermie

    36
    Jul 23, 2005
    ... test # 2 upsizing 600%.

    [​IMG]

    Click on the image to view full-size, or better view in Photoshop.

    Herman
     
  14. Hermie

    Hermie

    36
    Jul 23, 2005
    One final remark:

    I find PhotoZoom a bit more aggressive on noise compared to Photoshop and Genuine Fractals. So take care of noise reduction before enlarging with PhotoZoom.

    Herman
     
  15. I made a Photoshop "web" action to convert images to sRGB and resize to a max of 900 pixels per side. Coming from PS7, I did the resizing in steps believing that would generate the best result. I'm now using CS2, so will re-do the action without the steps. I'll also change the action's resize to a max of 800 pixels per side, since that's what Smugmug and PBase would use for their Large viewing size. Thanks for the updated info on resizing.

    Glenn
     
  16. PS Action to Prepare Image for Web

    I typed out explicit instructions for creating a CS2 action to prepare images for the web -- converting to sRGB and resizing to an 800 pixel maxim on the longest side of the image. I did this for a friend who is not yet comfortable in Photoshop, so I thought I might as well post them here as well.


    Creating a “For Web” Action in Photoshop CS2

    Open an image in Photoshop CS2.

    At the bottom of the Actions Palette, click on New Set icon (3rd from right).

    Type in a name for your action set (e.g., “Web”) and click Okay.

    At bottom of Actions Palette, click on New Action icon (2nd from right).

    Type in a name for your action, scroll through until you find your newly created “Web” action set, and choose an Action Key. (An Action Key is optional, but recommended: later you can simply press the designated key to start the action). Press Record.

    Press Edit > Convert to Profile. Scroll through until sRGB appears in the white Profile box. Click Okay.

    Press File > Automate > Fit Image. Type 800 in the width and height boxes. Click Okay. Whether your image is in portrait or landscape mode, the maximum length of its longest side will be re-sized to 800 pixels. The shorter side will remain proportionate.


    At the bottom of the Actions Palette, press the Stop Recording icon on the far left. You’ve completed making your action.

    To apply this action to an image, just press the Action Key you designated. Or, go to the Actions Palette and find the Web action set. Highlight the name of your action and press the right facing triangle at the bottom of the Actions Palette to start your action.

    I find that most resized images need just a slight additional sharpening. If you want, you could include in the action your chosen sharpening method.

    You can apply the action to a group of photos destined for your web hosting site by using batch process.

    Glenn
     
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