Archived posting to the Leica Users Group, 2004/02/22
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At 12:37 PM -0500 2/22/04, Jonathan Borden wrote:
>On Feb 22, 2004, at 11:40 AM, Frank Dernie wrote:
>
>>None of what you write here agrees with my practical experience.
>>The grain on my scanned negative film is much uglier than digital -
>>but scans of transparencies ar OK. I have certainly never used a
>>photoshop grain filter - the idea that this would make a more
>>pleasing image is at best a matter of opinion.
>
>I agree the appearance of film grain is a matter of opinion.
>Nonetheless 1) people have gone to the trouble to write photoshop
>filters that *add* grain to digital images 2) gaussian noise is much
>more pleasing than pixelated noise at any given level of noise.
The gaussian blur filter existed in Photoshop from a very early time,
when it was intended to simulate photographs in drawings done on a
computer, and other image softening effects. The digital photo market
was a _very_ minor factor at that time, but scanned photos were
becoming a significant factor, and gaussian blur was useful when
compositing and drawing to blend photos which had grain and blur.
>>There are certainly no visible "rectangular grains" in any of my
>>pictures, but I have never owned a camera with fewer than 2.2
>>megapixels. This camera made reasonable 10x8 prints, considering it
>>is a P&S camera.
>That roughly corresponds to a printing resolution of 75 dpi. You
>might find that acceptable. I am saying that many people would print
>an 8x10 at 300 dpi which is four times that resolution.
I think your math is a bit adrift. If 8x10 corresponds to 7.2
megapixels at 300 dpi, then 2.2 megapixels will result in an 8x10 at
166 dpi. This makes a huge difference from 75 dpi, although I agree
that the quality is noticeably poorer.
>>The earliest digital cameras did produce a mosaic effect and were
>>unusable for normal photography.
>>I have never heard 360 ppi quoted as a maximum resolution,
>
>The Imageprint RIP uses this as a maximal resolution (at least the
>lite version). I personally can't see any significant increase in
>print resolution (with my naked eye) beyond this. You can certainly
>print at a higher resolution -- I am only suggesting that this may
>not result in a better print.
>
>I *am* saying, however, that most people can see a difference
>between 75 dpi and 300 dpi (8 megapixel for 8x10) or 360 dpi (10
>megapixel for 8x10).
<snip>
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* Henning J. Wulff
/|\ Wulff Photography & Design
/###\ mailto:henningw@archiphoto.com
|[ ]| http://www.archiphoto.com
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