New Post: create valid barcode image

I've added

 image.get_Depth();

before

 image.Write(@"c:\test.bmp");

and returns 1 although the generated file has bit depth 32 according to windows
see here

and 8 according to identify

identify c:\test.bmp
c:\test.bmp BMP 240x100 240x100+0+0 8-bit sRGB 96.1KB 0.000u 0:00.000

if i remove

image.Read(barcodetxt);

then

 image.get_Depth();

returns 8 and identify (and windows) shows 1 bit depth

identify c:\test.bmp
c:\test.bmp BMP 240x100 240x100+0+0 1-bit sRGB 2c 3.35KB 0.000u 0:00.000

Of course, the resulted image is just a white background...

What else can I try?