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FORUMS Post Processing, Marketing & Presenting Photos RAW, Post Processing & Printing 
Thread started 15 Sep 2007 (Saturday) 22:07
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"selective" jpg... does it exist?

 
montreal
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Sep 15, 2007 22:07 |  #1

Ok... Just a thought here for something I think should exist... Perhaps it does already...

Is there any way to "tell" Photoshop « Don't compress to heavily in this particular area of the picture [Because that's where the bird/person/cat/whatev​er is]. The rest, where there's just shrubs, sky, grass, etc, you can compress more to save space. »

I'm thinking such a function would be useful, especially for posting pictures on the web, when you want small files but you don't want your main subject to have compression artefacts.

Does it already exist?


5D - 17-40L, 70-200L f4, 50 f1.4, PowerShot A430

  
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swalter
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Sep 16, 2007 03:15 |  #2

Yes, this has been around for quite a while. Photoshop has it built-in. Search the help file or google for weighted optimization to see how you can do it.

-Scott


http://scwalter.smugmu​g.com/ (external link)

  
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Swift
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Sep 16, 2007 07:55 |  #3

Wow, never thought of that. Didn't know it even existed.

Tutorial #1:
http://www.websiteopti​mization.com/speed/twe​ak/weighted/ (external link)

Tutorial #2:

To use masks to modify JPEG quality:

1. In the Optimize panel/palette, choose a JPEG setting from the Settings menu, or choose JPEG from the file format menu.
2. Click the mask button mask button to the right of the Quality text box.
3. Choose which masks to use:
* All Text Layers to use the masks from all text layers in the image.
* All Vector Shape Layers to use the masks from all shape layers in the image.
* Channel to choose an alpha channel from the menu. In ImageReady, you can choose Save Selection to create a new alpha channel based on the current selection.
4. To preview the results of the weighted optimization, select the Preview option.
5. Define the quality range:
* To set the highest level of quality, drag the right (white) tab on the slider, enter a value in the Maximum text box, or use the arrows to change the current value.
* To set the lowest level of quality, drag the left (black) tab on the slider, enter a value in the Minimum text box, or use the arrows to change the current value.
6. Click OK.

Learn something new every day, thanks Swalter.

Canon 550D | Canon 70-200mm f/4L USM | Canon 17-55mm f/2.8 IS USM | Canon Speedlight 430EX | Raynox DCR-250 Macro

  
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montreal
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Sep 16, 2007 10:02 |  #4

Great! I'm so glad it exist... I'll check it out. Thanks guys!


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"selective" jpg... does it exist?
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