that is 6 times the width of the screen. This rule fits the screen to the audience and not to the pro- jector. To make the image conform to the screen size, the proper lens must be selected. This rule works  the  same  for  all  screens  including  rear projection.   For   satisfactory   viewing,   a   row   of seats should be no wider than its distance from the screen. PERMANENT   SCREENS.—There   are several   types   of   built-in   screens.   Some   are portable  screens  that  have  been  mounted  on  a wall—the   screen   can   be   pulled   down   when needed  and  retracted  when  not  in  use.  Another type is a wall-mounted surface which is covered by draw curtains or sliding panels when it is not being  used.  A  third  type  is  one  that  is  actually mounted  on  a  sliding  panel  which  can  be  rolled into  a  wall  recess.  Some  screens  are  stored  in ceiling recesses and are raised and lowered elec- trically. When a presentation facility is not available, an  appropriate  portable  screen  that  will  fit  the size  of  the  room  and  the  audience  should  be selected.  When  the  chaplain  or  RP  supervisor gives an assignment to assist with an audiovisual presentation,  the  RP  should  list  the  location, date,  time  of  the  presentation,  and  the  type  of AV  equipment  needed.  With  this  information  at hand,  the  RP  should  be  able  to  rig  the  facility and assist in the conduct of the presentation with little  difficulty. When  the  audiovisual  equipment  and  acces- sories that will be needed have been determined, the next step is their acquisition and testing. Pro- cedures for mounting the components, as well as the  testing  and  adjustment  procedures  for special   equipment   should   be   found   in   the manufacturer’s  instruction  manual. Having  mounted  all  of  the  components,  the RP  should  now  be  ready  to  set  up  the  projector where  it  will  be  used.  Presentation  rooms  with projection  booths  greatly  simplify  the  problems of selecting and setting up equipment. FINAL  PREPARATION Attention   to   detail   in   the   final   minutes before  a  briefing  will  determine  how  well  a presentation will go. Plenty of time to set up and check the operation of the equipment before the presentation  should  be  allowed. The RP should setup the projectors and con- duct an operational check. When a presentation consists  of  slide  trays  or  transparencies,  they should  be  arranged  in  their  proper  order  of presentation.  When  operating  any  type  of  pro- jector,  the  cooling  fan  should  be  running  when the  projector  lamp  is  on.  Operating  a  projector lamp  without  the  cooling  fan  can  cause  serious damage  to  the  projector. The   projector   must   be   aligned   with   the screen. A sample transparency can be placed on the  projector  and  the  image  adjusted  vertically and  horizontally  to  the  screen;  then  the  image can  be  focused.  The  cooling  fan  should  always be left on for a few minutes after the projection lamp  has  been  turned  off  to  allow  the  unit  to cool  down. Appropriate  background  music  to  entertain early   arrivals   is   often   desirable.   The   volume should be loud enough to be heard easily but not so  loud  that  it  interferes  with  normal  conversa- tion. The music should be gradually faded out as the presentation begins. OTHER  RESPONSIBILITIES Although  not  listed  as  part  of  the  official duties  of  an  RP,  it  is  customary  to  assist  the presenter in other areas of the presentation when requested.  The  RP  may  be  called  upon  to distribute  agenda  or  literature  to  the  people  in attendance  or  asked  to  take  attendance.  These are very minor tasks but they help to make the presentation  go  smoothly.  Cooperation  between the  RP  and  the  presenter  is  necessary  if  a  suc- cessful presentation is to be achieved. So  far  in  this  chapter,  the  importance,  the planning,  and  the  use  of  presentations  for  pur- poses  of  instructing,  informing,  persuading,  and entertaining  have  been  discussed.  The  use  of audiovisual  materials/equipment  in  these presentations,   and   the   operation   and   routine maintenance   of   this   equipment   have   been addressed.  In  order  to  make  this  job  easier  for the RP, and to serve as a ready reference in the operation   and   maintenance   of   audiovisual equipment,  the  final  section  of  this  chapter  will be  devoted  to  descriptions  of  the  operation  and 7-15