Sharpening disabled when scaling up + compression oddities

Jochen Kratschmer

• 2008年03月25日 18:22

1.
Upscaling with the output seems to disable the sharpening completely. Is that a bug or have I overseen something? The disable-checkbox is unchecked of course, but I could not find a checkbox that enables sharpening only to the previews as mentioned on page 57 of the user guide.

2.
Compression for 8-bit-TIFFs leads to strange results:
uncompressed: 24,1 MB
LZW-compressed: 28,3 MB (even bigger than uncompressed)
ZIP-compressed: 22,9 MB
LZW-compressed with Photoshop: 19,6 MB
ZIP-compressed with Photoshop: 17,2 MB

How and why does this occur? So far I have to do LZW with Photoshop like with 3.7.

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  Paul Steunebrink

  • 2008年03月25日 20:15

  [quote="jo" wrote:
  1.
  Upscaling with the output seems to disable the sharpening completely. Is that a bug or have I overseen something? The disable-checkbox is unchecked of course, but I could not find a checkbox that enables sharpening only to the previews as mentioned on page 57 of the user guide.

  
  Had not used upscaling (much), but I confirm CO4 disables sharpening (tested with 200%). Must be a bug. The line on p 57 of the manual is also off. The disable sharpening checkbox on the Output tab is the only option I know about.
  

  [quote="jo" wrote:
  2.
  Compression for 8-bit-TIFFs leads to strange results:
  uncompressed: 24,1 MB
  LZW-compressed: 28,3 MB (even bigger than uncompressed)
  ZIP-compressed: 22,9 MB
  LZW-compressed with Photoshop: 19,6 MB
  ZIP-compressed with Photoshop: 17,2 MB

  
  Not the same experience here. An Leica M8 DNG (10 mp) converted to 8-bit TIFF uncompressed (34.5 MB), with LZW (28.1 MB) and ZIP (23.8 MB). Saved with PS CS3 the values are uncompressed 29.6 MB / LZW 16.3 MB / ZIP 15.2 MB.
  Note that the compressed file size varies with eac image. I used the same image here. In general I get smaller files from LZW and ZIP from CO4, but CS3 saves them in a smaller package than CO4, no doubt about that.

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  NN635868876750434892UL

  • 2015年12月28日 07:25

  TIFF images retain good quality, but they can take up a lot of disk space. But there are ways to make them smaller without sacrificing quality.
  
  Both ZIP and LZW are lossless compression methods. That means that no data is being lost in the compression, unlike a lossy format like JPG. You can open and save a TIFF file as many times you like without degrading the image. If you try that with JPG, the image quality will deteriorate more each time. So you can rest easy: using TIFF compression will not degrade your image quality.......more.
  
  William

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