Archaeology Magazine - June 1972 - 66

New Camera for Archaeological Use
The development of multi-band cameras, capable of taking three series of
simultaneouspictures, promisesto be of
great value to the archaeologistin his
use of aerial photography,a method he
has used for many years to help find and
interpret remains. It makes possiblethe
comparisonof a variety of film/filterexposures taken simultaneously of the
same area. Repeated flights under different light conditionsat different seasons would even compound its results.
The multi-band camera described here
is built especiallyfor fieldworkin archaeology.
Subterranean remains, such as walls,
roads, paths, floors, drainage systems,
wells, holes and other ancient disturbances can over the years cause tell-tale
effectson the surface which can be detected if the area is viewed from a distance. These signsmay appear in subtle
modulationsof the surface as revealed
by light and shade. Patterns of vegetation, either in the kind of plants or their
relative quality, may be influenced by
remains well below ground level and
show up on color or infra red film. Soil
conditions may have been affected by
ancient works, long since covered, and
appear relativelydamp or dry. Thermal
radiation from buried material may provide its own spectral signature if only
by affecting the pattern of an early
morningdew. Infiltrationof foreignmaterial into the earth, such as limestone,
may provide its own signature on the
surface.
This particular multi-bandcamera, of
modest size and weight, is constructed
for the various types of flight I use over
an archaeologicalsite. It can be mounted
in, or hand held from, a conventional
aircraft or a manned balloon. It can be
suspendedbelow an unmanned tethered
high flyingballoon,with its camerascontrolled by ground radio.
Interpretation of results from three
differentfilm/filtercombinationsmay be
done by the direct examinationof films
or prints as well as by the projection in
a multi-spectral additive color viewer.
The latter separates out the various
spectral signatures through light filters.
These proceduresare well establishedin
geology,agriculture, hydrologyand soil
analysis, and can be readily used for
archaeologicalpurposes.The RoyalCommissionon HistoricalMonumentsin England has already achieved notable successover sites in Great Britain.
There are many usefulfilm/filtercombinations employingconventionalblack
and white film as well as color and infra
234

red, all dependingupon the mission,the
situation and the season.
Whereasmulti-bandcamerasare generally four-band, this design is confined
to three, being sufficientfor the film/
filter combinationsmost applicable to
archaeological work. Weight gives it
great flexibility.Its twenty-three pounds
may be lifted by an unmanned tethered
balloon of a size manageableby a twoman ground crew, while still providing
sufficientextra lift to meet modest air
currents while in flight. It may be managed by hand from a manned balloon
gondola, mounted in a power plane or
on a standard tripod for work on the
ground.
The assemblyconsistsof three EL 500
Hasselblad cameras in a metal frame
which also carries various operating accessories:the electric commanduniting
the cameras,a strobe tell-tale signal and
a levellingbubble. Lensesare Carl Zeiss
Distagon50 mm. Film magazinesare for
70 exposure70 mm. perforated roll film
or for 24 exposure220 roll film according to the extent of the mission.Cameras
are mounted to a common orientation
and with precisionto make sure that the
three optical axes are parallel. Thus the
three resulting transparencies may be
viewedin a commonorientationacrossa
light table or be projectedin registerwith
a multi-spectral additive viewer. One
camera carries fiducialmarks for photogrammetricmap plotting.
The multi-bandcan be surroundedby
a heavy wood handling frame in which
the basic metal frame to which the cameras are locked is cushion mounted to
minimize vibration. When flown in a
power plane the wood frame is spring
mounted. When flown below the unmannedtethered balloonthe woodframe
is replacedby a magnesiumgimbalwhich
may be balanced for true vertical or
oblique coverage.A radio reception antenna is then attached to the outer
frame of the gimbal.The suspensionsystem belowthe balloonis so designedthat
the camera maintains a predetermined
directional orientation governed by air
movement which cannot, however, be
fully maintained in a flat calm.
The multi-band assembly may be
flownwith only two camerasor even one,
dependingon the mission.Conventional
color slides are generally sought along
with black and white photographs.The
gimbal may be adjusted to balance
quickly for any such combination of
cameras. Vertical or predetermined
oblique control is well assured even
when flown below the unmanned tethered balloon whether .at the height of

half a mile or a hundred feet, as illustrated in my article "Tethered Balloon
for ArchaeologicalPhotos" in PhotogrammetricEngineeringMagazine(February 1970, 181-186).
Cameramountingis such that the film
magazinesmay be removedand reloaded
and replaced without withdrawingthe
cameras from the frame. Each camera
is firmly anchored at three points but
may be releasedby a singlethumbscrew.
The separation of 8.375 inches between cameras 1 and 3 providesrealistic
three dimensional imagery from exposures taken in unison. Separationfor
a 60% overlap for stereo plotting is
gained by sequentialexposuresin flight
controlled by an intervalometeror by
hand. Simultaneousrelease of cameras
via the commandunit may be by manual
button, extensioncord to a cock-pit,or
radio from the groundwhenflownbelow
the unmanned tethered balloon. The
intervalometerapplies only to constant
speed flight with a power plane.
This summer, use of the multi-band
camera will be made over archaeological
sites in New Mexicoand Mexicounder
the auspicesof the UniversityMuseum
of the Universityof Pennsylvania.These
willbe by powerplane. Other suchflights
will also be made over sites in England
with the Royal Commissionon Historic
Monuments.These will be followedby
unmanned tethered balloon flights over
sites, both land and water, in Lebanon
and Iran, again for the UniversityMuseum. Finally we hope to cover more
water sites in Greece.
Workingdrawingsfor the multi-band
were prepared by the author. Precision
constructionand mountingwas by P. W.
Winter, Inc., of New York City. Mr.
Winter's contribution to refinements
during constructionwere most valuable.
Julian H. Whittlesey
UniversityMuseum

Archaeology Magazine - June 1972

Table of Contents for the Digital Edition of Archaeology Magazine - June 1972