Bitblt monochrome conversion

Why does this not work? When the bitblit writes back into the picture1 picbox it is just toally black?

btmp = CreateBitmapForm1.Picture1.ScaleWidth,Form1.Picture1.ScaleHeight, 1, 1, 0&)
chdc = CreateCompatibleDC(Form1.Picture1.hDC)
x = SelectObject(chdc, btmp)
'store bitmap to DC and then back to picture box this should convert bmp to monochrome format.

l = BitBlt(chdc, 0, 0, Form1.Picture1.ScaleWidth,
Form1.Picture1.ScaleHeight, Form1.Picture1.hDC, 0, 0, SRCCOPY)

l = BitBlt(Form1!Picture2.hDC, 0, 0, Form1.Picture1.ScaleWidth,
Form1.Picture1.ScaleHeight, chdc, 0, 0, SRCCOPY)
Form1.Picture2.Refresh
btmp = SelectObject(chdc, x)
k = DeleteObject(btmp)
retval = DeleteDC(chdc)

btmp = CreateBitmapForm1.Picture1.ScaleWidth,Form1.Picture1.ScaleHeight, 1, 1, 0&)

'tyr this:
'btmp=CreateCompatibleBitmap(.......)
'don't select an exist bitmap which belong to another DC into a CompatibleDC

chdc = CreateCompatibleDC(Form1.Picture1.hDC)
x = SelectObject(chdc, btmp)
'store bitmap to DC and then back to picture box this should convert bmp to monochrome format.

l = BitBlt(chdc, 0, 0, Form1.Picture1.ScaleWidth,
Form1.Picture1.ScaleHeight, Form1.Picture1.hDC, 0, 0, SRCCOPY)

l = BitBlt(Form1!Picture2.hDC, 0, 0, Form1.Picture1.ScaleWidth,
Form1.Picture1.ScaleHeight, chdc, 0, 0, SRCCOPY)
Form1.Picture2.Refresh
btmp = SelectObject(chdc, x)
k = DeleteObject(btmp)
retval = DeleteDC(chdc)