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How to conserve the size of the file convert from tif to ppm

Posted: Fri Dec 23, 2005 5:44 pm
by yarrow
Hi, All,

I use nconvert to convert tif files to ppm. The size of my tif files are about
25M each. When i convert it to ppm, It becomes 75M each. The command
i use is:

nconvert -in tiff -ctype grey -colors 256 -out ppm -truecolors 1.tif

I wander is there any way to preserve the size of the tif file. I want 25M
ppm, not 75M. It is too big.

Thanks

Re: How to conserve the size of the file convert from tif to

Posted: Mon Dec 26, 2005 9:30 am
by xnview
yarrow wrote:Hi, All,

I use nconvert to convert tif files to ppm. The size of my tif files are about
25M each. When i convert it to ppm, It becomes 75M each. The command
i use is:

nconvert -in tiff -ctype grey -colors 256 -out ppm -truecolors 1.tif

I wander is there any way to preserve the size of the tif file. I want 25M
ppm, not 75M. It is too big.
PPM is uncompressed format, so it's not possible

Re: How to conserve the size of the file convert from tif to

Posted: Tue Dec 27, 2005 2:52 pm
by Guest
xnview wrote:
yarrow wrote:Hi, All,

I use nconvert to convert tif files to ppm. The size of my tif files are about
25M each. When i convert it to ppm, It becomes 75M each. The command
i use is:

nconvert -in tiff -ctype grey -colors 256 -out ppm -truecolors 1.tif

I wander is there any way to preserve the size of the tif file. I want 25M
ppm, not 75M. It is too big.
PPM is uncompressed format, so it's not possible
Yes, i see. But the thing is that my tif file is also not compressed. I checked the property of the tif file and the converted ppm in xnview. I saw that the tif uses 1 byte for each pixel, while ppm uses 3 bytes for each pixel. So my question is whether it is possible to have a ppm using 1 byte each pixel? or every ppm should use 3 bytes for each pixel?

Thank you

Re: How to conserve the size of the file convert from tif to

Posted: Wed Dec 28, 2005 8:12 am
by xnview
Anonymous wrote:
xnview wrote:
yarrow wrote:Hi, All,

I use nconvert to convert tif files to ppm. The size of my tif files are about
25M each. When i convert it to ppm, It becomes 75M each. The command
i use is:

nconvert -in tiff -ctype grey -colors 256 -out ppm -truecolors 1.tif

I wander is there any way to preserve the size of the tif file. I want 25M
ppm, not 75M. It is too big.
PPM is uncompressed format, so it's not possible
Yes, i see. But the thing is that my tif file is also not compressed. I checked the property of the tif file and the converted ppm in xnview. I saw that the tif uses 1 byte for each pixel, while ppm uses 3 bytes for each pixel. So my question is whether it is possible to have a ppm using 1 byte each pixel? or every ppm should use 3 bytes for each pixel?

Thank you
PPM is only in RGB mode