How to get a LZW tiff with 24 bit depth from pdf file using Ghostscript

I am using Ghostscript9.0, I try to generate a LZW TIFF images with 24 bit depth fro开发者_如何学Pythonm pdf file, I always get bit depth = 1 using this GS command:

gswin32.exe -dSAFER -dBATCH -dNOPAUSE -r200 -sDEVICE=tifflzw -sOutputFile=tmp.tiff myfile.pdf

I searched in several manuals:

http://ghostscript.com/doc/current/Devices.htm

http://www.ghostscript.com/doc/8.54/Use.htm

but I didn't find anything of parameters to do that.

I add an image example proporties that I would like to produce with gs:

Here we can see the bit depth (profondeur de couleur) = 24 and the image is compressed with LZW

It is clearly stated that the format tifflzw you have chosen is located in the section

The remaining TIFF drivers all produce black-and-white output with different compression modes

http://ghostscript.com/doc/current/Devices.htm

If you want a 24bit output you have to use tiff24nc instead and add specify the compression via the parameter -sCompression=lzw

gswin32.exe -dSAFER -dBATCH -dNOPAUSE -r200 -sDEVICE=tiff24nc -sCompression=lzw -sOutputFile=tmp.tiff myfile.pdf