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Topic : "File format question" |
Alan
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Joined: 05 Apr 2000
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Location: California
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 Posted: Thu May 11, 2000 5:27 am |
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Does anyone know how much quality is lost saving to PNG? I often archive my pics as PNG, and can't see any quality loss, but I don't know. Are there any on-line sources to describe file format properties in general? Basically, I am wondering what the best quality/size ratio file format is... or is that the thousand dollar question? 
-Alan |
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sfr
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Location: Helsinki, Finland
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| Posted: Thu May 11, 2000 5:41 am |
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There's no quality loss because PNG is a lossless format. I use compressed tiff for my own images though, it gives smaller files than PNG (at least most of the time).
I guess the format with the best quality/size ratio would have to be JPEG at near-maximum quality...
Saffron / Sunflower |
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Nex
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Location: Austria
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| Posted: Thu May 11, 2000 5:53 am |
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| PNG has the advantage of an alpha channel (like in transparent 89a gifs).. I guess thats the main feature of PNG. |
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Alan
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| Posted: Sun May 14, 2000 2:05 am |
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Thanks for the info. I thought anything with compression had some quality loss. Why would you not want to compress something if there's no quality loss? Is it slower to load? Even so I would think less space would be more important.
-Alan
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Frost
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Location: Montr�al, Canada
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| Posted: Sun May 14, 2000 5:50 am |
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PNG is a very good format. Of course, any compresed file format needs some time to decompress, but the time spent is usually much the same as loading the extra raw data in a raw data output file format. PSD is alcompressed and also lossless, so PSD isn't all that bad either for local storage... too bad browsers don't support it.
Danny 'frost' Oros |
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29A
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Joined: 08 May 2000
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Location: Stockholm, Sweden
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| Posted: Sun May 14, 2000 6:49 am |
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I think the reason browsers doesn't support PSD's is becasue Adobe wants license fees for anything that uses the format...
the spec for PNG is available at www.w3c.org, you might want to have the specs for DECOMPRESS also, RFC 1950 and RFC 1951 if I remember correct.
PNG is a kickass format. The main reason of why not to compress your images is depending on the laziness of coders ...
PNG's compression method is a b***h to implement, the same that ZIP uses btw...
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I'm not defect!
[This message has been edited by 29A (edited May 14, 2000).] |
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Affected
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Joined: 22 Oct 1999
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Location: Helsinki, Finland
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| Posted: Sun May 14, 2000 6:58 am |
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Still, from what I've seen, PNG files are too big for web use.
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Affected
Democracy is a lie
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Stolln
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Joined: 24 Jan 2000
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Location: Connecticut - USA
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| Posted: Sun May 14, 2000 7:05 am |
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Erm, Quicktime 4 has a PSD importer for web browsers. This enables you to see PSD's through your browser.
Just thought I'd pop this up.
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