a  large  degree,  the  amount  and  type  of  lighting required.  When  nonprojected  aids  are  being used, normal lighting of the room is satisfactory. When projected aids are being used, the required intensity of the lights will vary with the type of projector  being  used.  The  presentation  room should  not  be  totally  dark  when  visual  aids  are projected  on  the  screen.  However,  darkening  a room  sharpens  the  projected  aid,  brings  out details,  brightens  the  color,  and  helps  hold  the interest  of  the  viewer.  Too  much  light  in  the room makes viewing hazy and causes eyestrain. Random  rays  of  light,  especially  at  the  side  or near  the  screen,  are  distracters.  Sometimes  the effective  use  of  nonprojected  charts,  graphs,  or maps  is  prevented  by  the  glare  of  light  from  a window.   These   conditions   can   be   prevented through  the  proper  use  of  shades  and  artificial lighting.  Light  intensity  just  below  the  level  of interference  with  good  viewing  should  be  main- tained.  If  the  room  has  windows,  and  the  win- dows  are  needed  for  ventilation,  light  from  the windows may be controlled with venetian blinds or  with  baffles,  Louvers  may  also  be  used  to darken  a  room. Heating  and  ventilation  are  very  important, especially where windows must be used partially for  regulating  the  heating  and  ventilation.  Only in  rooms  equipped  with  self-regulating  heating and  ventilating  systems  is  the  RP  relieved  from the   responsibility   of   regulating   these   factors. Humidity  is  another  important  factor  in  main- taining  comfort.  Even  when  the  temperature  is favorable,  people  may  be  uncomfortable  if  the humidity  is  too  high.  Humidity  may  not  be  con- trolled,  but  comfort  will  be  greatly  improved  if the air is kept moving. The circulation of the air is usually accomplished by motor-driven fans or, if it is a breezy day, by adjusting the windows. Overall Conditions The  overall  condition  of  a  presentation facility should be clean and neat in appearance. A  general  inspection  should  be  made  after  each usage  of  the  presentation  facility.  The  floor should be clean and free of debris. If smoking is permitted,  ashtrays  and  ash  stands  should  be emptied, cleaned, and evenly redistributed in the room.  Some  realignment  of  chairs  is  usually necessary.   The   room’s   displayed   articles,   pic- tures,  clock,  calendar,  flags,  etc.,  should  be visually  checked  to  make  sure  they  are  in  place and   set   up   properly.   The   projection   screen should  be  clean  and  free  of  smudges.  If  tables are used, a writing pad, pencils, and an ashtray should  be  set  up  at  each  conferee’s  position. Correct   placement   of   nameplate   holders   at reserved positions is a must. Normally, seats are reserved  for  flag  officers,  distinguished  visitors, deputy  chiefs  of  staff,  and  staff  members.  Pro- tocol prescribes the seating arrangement and can guide you in these matters. The proper seating of foreign  dignitaries  and  religious  leaders  is  very important.  Questions  about  reserved  seating arrangements  may  be  discussed  with  the chaplain. AUDIOVISUAL   EQUIPMENT After  arranging  the  presentation  room,  the audiovisual equipment must be selected and set up. The type of material to be presented must be determined;  then  the  proper  equipment  and accessories  compatible  with  the  presentation facility  should  be  selected. Projection  Screens There  is  more  to  a  projection  screen  than  is readily  apparent,  It  is  true  that  images  can  be projected  on  a  wall,  a  door,  or  a  bed  sheet.  But that  is  not  the  best  way  to  present  a  quality image.  The  surface  of  a  projection  screen  is designed  to  reflect  the  most  light  possible.  One of the most common types of screens is the glass beaded  surface  which  is  very  bright,  yields excellent  color  reproduction,  and  has  a  very wide  viewing  angle.    The  newer  screens  are seamless and are available in almost any size. Another type of screen is the silver lenticular surface.  It  is  described  as  lenticular  because  it controls light, much the same way as does a lens, by  directing  it  to  a  predetermined  area.  Light that  would  normally  be  wasted  through  disper- sion  is  reflected  back  to  the  audience.  Images projected  on  a  silver  lenticular  screen  are  as bright as the newest glass beaded surfaces. The viewing angle for this type of surface is approx- imately   90°.   Lenticular   screens   work   well   in rooms  that  cannot  be  darkened,  particularly  if 7-13