Item Subject: cc:Mail Text

     For most DIN headlights and most "EURO" headlights that have
     replaceable elements, the Hi-Lo beam has a designe feature that
     provides a very distinct "cut-off" of the beam.  The visible light
     above the cutoff on low when looking at the light rather than looking
     with the light is very low intensity.  Below the cutoff the light is
     much brighter.  The feature provides the very best rain/fog/snow
     performance and has the additional advantage of not "dazzling" the
     oncoming driver as the cutoff section covers the opposing traffic lane
     in relative shadow.

     On high or high+low the beam is of course not baffled and will as you
     would expect 'dazzle' the oncoming traffic.

     For a vanagon this presents an interesting problem.  If you aim your
     lows to illuminate the road fairly far away but still with a down
     cutoff, the high beams are suitable for jacklighting owls.  If you aim
     your high beams so they point parallel to the road surface the lows
     are quite suitable for jacklighting tarantulas.  Has to do with the
     relatively high placement of the lamp center with respect to the road.

     Carello, Cibie, Marchal, Lucas and others produced some special 7"
     round lights that have their focus adjustable for low or high
     placement on the vehicle.  The most famous were the dual bulb Carellos
     and the Marchal Ampilux.  Fitted with 100 and 130 H1 bulbs these were
     the answer at Daytona, Sebring, Le Mans and the Bol d' Or for race
     cars that had very low light centers.  No dazzle and difficult to
     overdrive even at race speeds.  Alas, no more.

     The cutoff design permits adjustment for no dazzle regardless of the
     lamp intensity on low beam so "blinding" other drivers is merely a
     case of poorly adjusted headlights and has no bearing or relevance to
     the H4 or H1-H1 designs.

     The H4 is a fixed focus unit and doesn't permit independent filament
     placement so we have an inherent design compromise which still doesn't
     dazzle the oncoming driver.

     Cibie made a Z-beam which instead of the tipped up RH beam pattern had
     a horizontal sharp cutoff LH side with an elevated but also horizontal
     sharp cutoff RH side (on a per headlight basis of course, R and L are
     indentical.

     For LH driving countries such as NZ and Merrie Old there is an
     opposite lamp which has the cutoff on the right.

     Wish I'd never sold the Ampilux with the TI Super.

     al