OPN/CLS(OPCS)		Optical Printer Control System		OPN/CLS(OPCS)

    NAME
        opn  - open the fader shutter
	cls  - close the fader shutter

    EXAMPLES
       opn		# opens the fader
       cls		# closes the fader

    DESCRIPTION
       opn and cls allow the user to open or close the fader directly. 
       
       To move the fader to positions other than OPEN or CLOSED, use the 
       SHU(OPCS) command to specify absolute degree positions for the fader.

    NOTES
       Specifying OPN or CLS during a pending fade or dissolve will effectively
       cancel the fade/dx, and send the fader to the specified position.

       The system will not acknowledge the ALLSTOP key until AFTER the fader
       has completed running to its position.

       OPN uses the INTERP(OPCSDEFS) command's [high] value to determine the
       degree position for OPEN on your system, and the [low] value to 
       determine the degree position for CLOSED.  Most cameras have 170
       degree shutters, but some have 120. See INTERP(OPCSDEFS) for details.

    SEE ALSO
        OPCS Commands
        CAM(OPCS)            - shoot camera (fades/dissolves too)
        OPN(OPCS), CLS(OPCS) - open/close fader shutter
        SHU(OPCS)            - move fader to an absolute position in degrees
        DXI(OPCS), DXO(OPCS) - set up dissolve in/out
        FDI(OPCS), FDO(OPCS) - set up fade in/out

        OPCSDEFS Commands
        FLOG(OPCSDEFS)   - set Fader LOGarithmic curve for custom fades
        FRANGE(OPCSDEFS) - set fade/dx's degrees range (for Hicon film stocks)
        INTERP(OPCSDEFS) - set interpolation positions (fader, focus, etc)
        SLOP(OPCSDEFS)   - correct for slop in a motor (fader, focus, etc)

        General
        MATH(DOCS)       - math expressions (for use in frame specifications)
        SYNTAX(DOCS)     - online calculator and OPCS math expression syntax
        INTERP(OPCSDEFS)	- setup interpolations for fader, etc.

    ORIGIN
	Gregory Ercolano, Los Feliz California 11/29/89