How do I create a 32 bit CMYK file.

[derekjohn37]

I am trying to create a 32 bit per pixel (8bit per channel) bitmap from 4 GDI+ bitmaps, each one representing C,M,Y and K. I am using bitmap lockBits to load pixel data into the 'pixels' byte array, Code below gives a 24 bpp file no matter what I do. Any idea what I am missing?

            var myMagickReadSettings = new MagickReadSettings();
            myMagickReadSettings.Width = Artwork.channels[0].Width;
            myMagickReadSettings.Height = Artwork.channels[0].Height;
            myMagickReadSettings.Format = MagickFormat.Cmyk;
            myMagickReadSettings.Depth = 8;
            myMagickReadSettings.Compression = CompressionMethod.NoCompression;
            myMagickReadSettings.ColorSpace = ColorSpace.CMYK;
            
            var output = new MagickImage(pixels,myMagickReadSettings);
            
            output.Write("Output.bmp");

[derekjohn37]

Slept on it then answered my own question. Should have used Tiff format not Bmp. 'output.Write("Output.tif");'
Bmp does not support CMYK. Silly mistake!