I am trying to export a 1 bit bitmap image as a windows .BMP so it can be imported into CorelDraw for laser engraving. When I do the import to CorelDraw I get the error "Invalid Header" when I try to import into LaserScript 5.3 I just get the outline of the image.

I create the bitmap from the menu Image>Mode>indexed. Then select 1bit image with Floyd Steinberg dithering.

I could open a Gimp 1 bit bmp in an old Coreldraw but I believe you. I have come across similar errors for RGB bmp for tracing using Autotrace.

Have you tried using command line Imagemagick (IM)

magick image-in.png -colors 2 +dither -type bilevel image-out.bmp

Comparing files from the same source, IM file size is a few bytes larger and that is the header. Inspecting the properties, identical except for chromaticity - strange entries for red + green from Gimp.

Worth a try.

Thanks for the reply, after reading your post I wondered if I could do the same job with a .png. I processed the image the same way and exported it as a .png. It worked fine and after four years discovered that my laser software (Lasercut 5.3) will import transparent png files. Many thanks

Peter