Unable to Copy 1bppIndexed to New 1bppIndexed?

        Dim bmpSource As New Aurigma.GraphicsMill.Bitmap
        Dim bmpDest As Aurigma.GraphicsMill.Bitmap


            
        Dim tifReader As New Aurigma.GraphicsMill.Codecs.TiffReader(strOldFileName)

            

        tifReader.Open(strOldFileName)

            
        With tifReader.LoadFrame(0)
            .GetBitmap(bmpSource)

            Dim rctSource As Rectangle = GetSourceRect()
            
            bmpDest = New Aurigma.GraphicsMill.Bitmap(Aurigma.GraphicsMill.RgbColor.White, .Width, rctSource.Height, PixelFormat.Format24bppRgb)

            bmpSource.Draw(bmpDest, New Rectangle(0, 0, 0, 0), rctSource, Transforms.CombineMode.Copy, 0, Transforms.InterpolationMode.HighSpeed)
        End With

            
        bmpDest.ColorManagement.Convert(PixelFormat.Format1bppIndexed)
        bmpDest.Save(strNewFileName, New Codecs.TiffEncoderOptions(Codecs.CompressionType.Ccitt4))
       
        bmpSource.Dispose()
        bmpDest.Dispose()