Legacy ImageMagick Discussions Archive

Hello, I am new to ImageMagick and am using it primarily for converting images from NEF. I am having trouble applying LZW compression when converting to TIFF. The file size is actually getting bigger when I apply LZW compression, as opposed to just converting to TIFF without LZW.

I am using:
ImageMagick version: Version: ImageMagick 7.0.3-9 Q16 x86_64 2016-12-8 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2016 ImageMagick Studio LLC
License: http://www.imagemagick.org/script/license.php
Features: Cipher DPC HDRI OpenMP
Delegates (built-in): bzlib fontconfig freetype jbig jng jpeg lzma pangocairo png tiff x xml zlib

LIBTIFF version 4.0.3
the 14 MB NEF is converted to a 61 MB TIFF. When I look at the file in ExifTool, it says there is LZW compression.
the 14.0 MB NEF is converted to a 53 MB TIFF.

Any ideas would be appreciated! Thank you!

Post an example NEF image to some place such as dropbox.com and put the URL here, so we can test with it.

What is your platform?

I am on ubuntu 14.04.

NEF file: https://www.dropbox.com/s/bmlnjebeg2ao7 ... 6.NEF?dl=0

TIFF where I didn't apply LZW: https://www.dropbox.com/s/fv8sihfkhfxb4 ... .tiff?dl=0

TIFF where I did apply LZW: https://www.dropbox.com/s/pf1jts13mj397 ... .tiff?dl=0

Thank you!

According to IM identify -verbose, your 16-bit per channel NEF file (48-bits) with zip compression has Filesize: 54.38MB

Using IM 6.9.6.7 Q16 Mac OSX:

RWK5836.NEF=>/var/tmp/magick-2465nmT5RIDjXb6.png NEF 4308x2860 4308x2860+0+0 16-bit sRGB 54.38MB 0.020u 0:00.020
RWK5836_none.tif TIFF 4308x2860 4308x2860+0+0 16-bit sRGB 73.93MB 0.000u 0:00.009
RWK5836_lzw.tif TIFF 4308x2860 4308x2860+0+0 16-bit sRGB 64.92MB 0.000u 0:00.009
RWK5836_zip.tif TIFF 4308x2860 4308x2860+0+0 16-bit sRGB 55.75MB 0.000u 0:00.000


Using IM 7.0.3.9 Q16 Mac OSX:
RWK5836.NEF=>/var/tmp/magick-2465nmT5RIDjXb6.png NEF 4308x2860 4308x2860+0+0 16-bit sRGB 54.38MB 0.020u 0:00.020
RWK5836_none.tif TIFF 4308x2860 4308x2860+0+0 16-bit sRGB 73.93MB 0.000u 0:00.009
RWK5836_lzw.tif TIFF 4308x2860 4308x2860+0+0 16-bit sRGB 64.92MB 0.000u 0:00.009
RWK5836_zip.tif TIFF 4308x2860 4308x2860+0+0 16-bit sRGB 55.75MB 0.000u 0:00.000

So my results do not show that lzw is larger than none!

According to EXIFTOOL, your NEF file is - FileSize: 13999013


Looking at the identify, it appears that IM is converting NEF to PNG to get filesize.

I am not an expert on NEF, so cannot say what is going on or how NEF is compressed.

NEF compression is proprietary to Nikon, and can be either lossy or lossless. The lossless compression gives smaller sizes than any method IM has. (I guess Nikon have a bigger budget.)

If LZW compression makes a result that is larger than no compression, the solution is: don't use LZW compression.

Personally, I use Zip compression for tiff files from NEF.