tryl wrote:When running the tif to tif conversion (which is run completely separate from the jpg to tif conversion) i get the error message:
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convert: Caution: quantization tables are too coarse for baseline JPEG. `JPEGLib'.
Are you sure that this warning comes from the second conversion (TIFF to TIFF), and not from the first conversion? With a current ImageMagick version, such a message can occur with certain JPG->TIFF conversions. But maybe you have an older ImageMagick version (or an older libtiff or jpeg library)...
Anyway: This is usually an effect of an input JPG having a very low quality. (With a current version, this happens if IM identifies a quality value of 23 or below.) The resulting TIFF should be still ok, but it's less compatible - some viewers might have problems with that.
What viewer did you use for these TIFF files? And: What ImageMagick version do you have (on which operating system)? If the version is old, then try to upgrade first.
tryl wrote:Running
produces a perfect result.
Even if you had no error: I wouldn't recommend the above command line - at least if you use the TIFF files as intermediate format. ImageMagick usually tries to use the compression method and the 'quality value' from the input file for a conversion (if you don't specify a certain compression). JPG compression can also be used in TIFF files - thus a standard JPG->TIFF conversion will result in a lossy recompression (which degrades the quality). I recommend using a compression that's not lossy - e.g. the ZIP compression (for a low filesize):
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convert picture.jpg -compress zip -quality 90 picture.tif
If you don't care about the filesize of your intermediate files, but about speed, then just use no compression:
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convert picture.jpg -compress none picture.tif