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Image size reduction

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kerrysr

Technical User
Sep 9, 2005
56
US
I have large files (used a 12meg pixel camera) that I am trying to reduce the image sizes. Unless I uncheck "resample image," everytime I shrink the image size, the photos look terrible (lose focus)The problem with unchecking the "resample image," is that it does a great job quality wise, but leaves huge files of 1000 dpi or more resolution. Is there a way (or a plugin) that I can reduce the resolution to 300, and still have a great looking photo?
 
If you just want to change the resolution (PPI) Pixels Per Inch (DPI = Dots per Inch, what you use for printing);
Select the Crop tool, remove any values in the Width and Height boxs and put your new resolution in the Resoution box. Select the whole document and double click. Your document is now at the new resolution.
 
...what resampling method are you using to lose such noticeable quality?

...there are different resampling methods in the latest photoshop, nearest neighbour, bilinear and three versions of bicubic...

...essentially, if you were to position your raw image into a layout application and export to pdf with image downsampling enabled, you would be performing a similar process to what photoshop would do. Depending on what resampling method you choose upon you can end up with quite different results...

...when resampling images it often helps to sharpen them at the end...

...if photoshop's resampling methods aren't satisfactory then verify the resampling method you have selected. If it is the bicubic algorithm being used then press quality PDFs won't be much good for your images either...

...the only alternative is genuine fractals really, but this is more involved with making images larger for poster work and costs a bit of money:


Andrew
 
...also worth noting that always, wherever possible, view your image at 100% as different magnifications can have images look more out of shape that they might otherwise really be...

Andrew
 
Bicubic sharper is the recommended method for reducing the size. What size are you downsizing to? What are the dimensions in inches and the pixels per inch? If you resample to 72ppi for an 8x10 image, the image will lose sharpness.
 
I agree with apepp for the method for classic photographs, even if I prefer to use nomal bicubic and a "controlled" post-sharpening method. The point to judge the result is to look at 100% to the screen. I use currently a 12Mpixels camera, like you, and do that all the time. On another way, when you uncheck "reample", you DON'T resize your image (so: no changes), you only change the print size, but change anything about the pixels !
 
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