monochrome bmp

How to I create a monochrome bmp in photoshop ? I have a logo I use for my business that has a white back ground, blue image and red letters. I have a screen saver that is asking for a black and white monochrome bmp.
I am using photoshop cs and only have a photoshop 5 book which isnt telling a whole lot other than checking monochrome under the channel mixer, but it still isnt working correctly so obviously I am doing something wrong.

any and all help would be greatly appreciated.

Thank you.
Hi flgirl,

Welcome to the forums!

First a definition...
Bit depth
The number of bits that are used to store a pixel's color information for display. Graphics are also often described by the number of bits used to represent each dot. A 1-bit image is monochrome; an 8-bit image supports 256 colors or grayscales; and a 24- or 32-bit graphic supports true color.

When you use a 1 bit image you will have only black or white pixels, there will be no grays so no anti-aliasing. Any overlapping images will merge as they will be all black. So...

I'd suggest using your Magic wand tool with anti-aliased checked but contiguous unchecked in the options bar. Click on the white area. Inverse the selection (Control Shift I = Command Shift I on a Mac). Fill with black.

Next, Image > Mode > Grayscale followed by Image > Mode > Bitmap. In the Bitmap dialog, I'd suggest changing the Resolution to 96 ppi and for Method you might want to experiment but '50% Threshold' probably will give you your best edges.

Now Save As..., choose BMP and your only option will be 1 bit.