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I need to collect 1000 uncompressed TIFF files. I have a large set of JPG images, so I decided to convert them to TIFF format. The loss in quality is ok in this case for me.

I used the following command to convert a folder of JPG images to TIFF:

mogrify -format tiff *.jpg -compress none

Even though I included -compress none, it somehow uses JPEG compression. How can I convert JPEG files to uncompressed TIFF files then?

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How have you determined that the resultant tiff file uses jpg compression? –  horatio Apr 4 '12 at 17:49
    
using imagemagick identify tool –  klijo Apr 4 '12 at 17:49
    
can you provide the dump? –  horatio Apr 4 '12 at 17:50
    
i ask it for a question and here it is superuser.com/questions/402829/… –  klijo Apr 4 '12 at 17:50
    
sorry, i meant can you provide some information that specifically says that it is a tiff file with jpeg compression after it is converted? Your link provides no ouput from a tool etc which would indicate what the compression method is. –  horatio Apr 4 '12 at 17:54
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3 Answers

up vote 2 down vote accepted

If you use imagemagick? and say

convert -compress none *.jpg Picts.tiff

Tell me if it works right for you

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Yes, use convert instead of mogrify –  Doug Harris Apr 4 '12 at 18:21
    
yup it worked thank you very much –  klijo Apr 5 '12 at 2:54
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Once an image is converted or created in jpg format, the detail is lost.

The "compression" in jpg is not like a zip file in which the file is made smaller but every bit still exists. Jpg uses lossy compression -- this means that some data is lost during the compression process.

The best you'll be able to do is to have a tiff file with the same quality as your (compressed, lossy) jpg.

To do better, you'd have to recapture the original in a non-lossy format.

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actually my problem is i need a collection of 1000 files in tiff format, and there is no other method of obtaining them other than converting jpg's to tiff. Therefore converting jpg to tiff is ok for my purpose. –  klijo Apr 4 '12 at 17:47
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TIFF supports lzw, zip, and jpg compression within the format via extensions. jpg compression handling is rare in tools, but Photoshop (for instance) supports its use. –  horatio Apr 4 '12 at 17:48
    
well tiff is able to store uncompressed format as well –  klijo Apr 4 '12 at 17:49
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Try -compress None as options once you have originals (as noted by @DougHarris).

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Iam not interested in the end quality of the converted images. I only need a collection of tiff files. Thats all –  klijo Apr 4 '12 at 17:52
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