BetterPhoto Member |
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Decompression of a JPEG
If you have a JPEG pic (100k 24 bit) that you want to print, can you somehow decompress the JPEG to a TIFF to gain quality for printing a enlarged picture?
March 17, 2002
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John A. Lind |
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Jeff,
No. When you make a JPEG, part of its compression algorithm deletes information from the original digital file to help make it smaller. The information "given up" to do this is not stored anywhere in the JPEG; it's gone. Thus, there's no method for recovering it from the JPEG file itself; you must revert back to the first, original file. You can convert a JPEG back to a TIFF, but all you get a large file with zero compression that contains no more information than the JPEG you started with.-- John
March 17, 2002
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Ken Pang |
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Just as a side note, you can use LZW compression on TIFF files originally to get them smaller. Not all viewers will support LZW on the fly decompression. Basically, LZW compression is lossless compression similar to WinZip or WinRAR. What comes out is byte for byte identical to what goes in. However, compression ratios are rarely better than about 15% as compared to sometimes 90% compression for JPEG. On the fly decompression just means that the viewer decompresses it before allowing you to view it - there are no extra steps involved, so that you can't tell that it's been compressed
March 17, 2002
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