Strange effects when just changing sizes

Hello,

Please have a look at these files:

http://www.the-grue.de/source.tif
http://www.the-grue.de/result.tif

I'm using graphics magick to convert a bunch of scanned files. The files are
black text on white background, one bit tifs. gm identify says this:

gm identify -verbose source.tif
Image: source.tif
  Format: TIFF (Tagged Image File Format)
  Geometry: 2918x4205
  Class: DirectClass
  Type: bilevel
  Depth: 1 bits-per-pixel component
  Channel Depths:
    Gray:     1 bits
  Channel Statistics:
    Gray:
      Minimum:                     0.00 (0.0000)
      Maximum:                   255.00 (1.0000)
      Mean:                      232.95 (0.9135)
      Standard Deviation:         71.67 (0.2811)
  Resolution: 157.48x157.48 pixels/centimeter
  Filesize: 157.7K
  Interlace: No
  Orientation: Unknown
  Background Color: white
  Border Color: #DFDFDF
  Matte Color: #BDBDBD
  Page geometry: 2918x4205+0+0
  Compose: Over
  Dispose: Undefined
  Iterations: 0
  Compression: Zip
  Document: source.tif
  Comment:  Image generated by GPL Ghostscript (device=pnmraw)

  Software: GraphicsMagick 1.3.20 2014-08-16 Q8 http://www.GraphicsMagick.org/
  Signature: df98437433973660a19c1d07daa1b1ee4b50f7ed4fd9d16bc7e0903268308dd2
  Tainted: False
  User Time: 0.090u
  Elapsed Time: 0:01
  Pixels Per Second: 130.0M


These scans all have different geometries. What I need is to put them onto a
page that has a fixed size, using a fixed border - think about a frame with a
fixed size where the scans are put into.

I have a script which does that just fine with tiffs that have a higher channel
depth. The main part of the script does this:

gm composite -compress LZW -geometry +0+118 -gravity North -resize 2244x3153
-units PixelsPerInch -density 300x300 source.tif
-size 2481x3508 xc:white result.tif

But when I run this, the result looks terrible: the background is black and the
text looks like some kind of edge-detecting filter has been used. That's the
output of gm identify:

gm identify -verbose result.tif
Image: result.tif
  Format: TIFF (Tagged Image File Format)
  Geometry: 2230x3153
  Class: DirectClass
  Type: grayscale
  Depth: 8 bits-per-pixel component
  Channel Depths:
    Gray:     8 bits
  Channel Statistics:
    Gray:
      Minimum:                     0.00 (0.0000)
      Maximum:                   255.00 (1.0000)
      Mean:                       19.99 (0.0784)
      Standard Deviation:         63.35 (0.2484)
  Chromaticity:
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Resolution: 300x300 pixels/inch
  Filesize: 2.9M
  Interlace: No
  Orientation: TopLeft
  Background Color: white
  Border Color: #DFDFDF
  Matte Color: #BDBDBD
  Page geometry: 2230x3153+0+0
  Compose: Over
  Dispose: Undefined
  Iterations: 0
  Compression: LZW
  Signature: 01606cb2591b54508a6fbc054bcf985c47706fa8a97c356da57b4687827d5c06
  Tainted: False
  User Time: 0.160u
  Elapsed Time: 0:01
  Pixels Per Second: 41.9M

Oh, and by the way: it's not correctly framed, either :s


Could you please help me find out what I'm making wrong? My "frame-page" script
is working find, just not for these 1 bit images... (I think).

cu
-- 
Markus Grunwald
https://www.the-grue.de

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