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Tiff to tiff converstion gives size and qaulity difference for final tif in v7.0.7-7 and v6.9.1-0

Posted: 2020-01-05T05:29:20-07:00
by jyoti.dash
When i convert a tif file using the following commnad to tif i get a size and qaulity differnece between the final tiff files between two version of Imagemagick. Can i know what is causing the differnece in size and quality?

Convert.exe -limit area 100mb "C:\Users\Ephesoft\Documents\multipage-pdfCopy-0001.tif" -compress LZW "C:\Users\Ephesoft\Documents\converted-%04d.tif"

example
Original tif fiel szie -181KB
in Version 6.9.1-0 the final tif file size after running the above command is 91KB
in Version 7.0.7-7 the final tif file size after running the above command is 109KB

In some cases the size of a final tif file is smaller in the newer version 7.0.7-7 compared to the final tif size in 6.9.1-0 Which affects the quality of the final tif file.

Can i know how these 2 versions of Imagemagick version is creating a tif of different size and quality even though the command is the same and the oringla file is the same?

Re: Tiff to tiff converstion gives size and qaulity difference for final tif in v7.0.7-7 and v6.9.1-0

Posted: 2020-01-05T07:18:10-07:00
by snibgo
Most compression methods for tiff (eg zip and lzw) are lossless, so the quality will be unchanged. Some (eg jpeg) are lossy, so the quality will reduce.

Look at "identify -verbose" for each of the files. What is the compression method of the input and two outputs?