Weston Foot-Candles Measurements & Controlling Exposure User manual

CONTROTTING EXPOSURE WITH THE WESTON METER
                                Chopler 4z  Color Work


      T}Ilven when equipped with
 all the gadgets recommended bY
 the experts, color transparencies
 are often unsatisfactory. This is
 seldom the fault of the equiP-
ment. More likely it wasn't'handled          to the best advantage.
    The follorving points are al-
 ways important, and must be ob-
 .served to assllre good v'{}slllts.
        t.  E.x1)ost) colot' filrrl ottlf in
 the kind of light it wa$ made for.
 If a different light source mustbe employed, be guided by the                                                !;,i  ffi fiIm manufacturer's instructions  W
 f or using color-compensating
 filters.                                        Weston Exposure Meter Control Diol
     2. Be sure the exposure me-              Showing "A'I ond "C" Color Film Limits
 ter is set to the proper emulsion
 rating for the color film being                                                                       ((                                                                                see how we can used. If the meter is a Weston   Weston dial by the letters          Now, let's                                                                    manipulate these factors to select Master II, this is simple. The   and "C",  (See dial above.)^"                            These positions, coupled with   the exposure that will give the Weston Emulsion Speed values
 for color film are the result of    the Brightness Range Method of    best color rendering. In a typical                                    determining the exposure, afford    scene with a brightest-color value careful tests in the Weston Photo-                              the most accurate means of   of 200 and a darkest-color value graphic studios and outdoors.                                 getting the best results. The   of 50, the ratio is 4:7. This can They are integral factors in the
 correct operation of Weston Ex-    Brightness Range Method is tak-   be exposed correctly by placing
 posure Meters, and for others    ing close-up readings of the dark-   the Arrow midway between ; in
 designed f or use with these    est and brightest important col-    this case, at 100. Now the A and                                                      rrcene, exclusive of  C positions naturally coincide values.                        ors in the                                    blacks and wliites, which are not   with the brightness-rirnge  ex-
     3. Naturally, the better one                                        tremes.
 understands the operation of the                                                                                                                         is an idea'l situation meter, al'td the rnore intelliger.th'        747'"4,r,                    Rut this                                                                                                                              {/                  that rarely oc,:ilrs. f-Isllally the he interprets the l'eadings. the            i,la C\)  I                  scr)ne's l-lrigirLi\css range is more certain he is of obtaining                                                                                gr"eater than 4:L. Above and be- correct camera settillgs. Every-                                                                low these extremes, you lose col- thing required for perfect results   #.F                                                               or quality by overexposure and is contained on the exclusive ex-                                                                   underexposure. So, without the posure control dial of all Weston                                              A ancl C positions on the Weston Universal Exposure Meters. This                                 -  f,       ru                                                                                dial, and the selective exposure includes, for the sake of con-                                                                       control they permit the photo- sistently good color work, the                                                           grapher would be lost. With extremely valuable A and C posi-                                                                other reflectecl-light meters he tions"                                                                         rnight estimate a mid-point ex-
      Selective Exposure Control                                               posure, but that is all. He couldn't
                              Reqd Brightest ond Dorkesl Areos     eo'ntr"ol the exposure according to
    The permissible scene con-            for Brightness Ronge           the merits of the scene, as he can trast for color film is about I:4,                                                                         three \ilays u'ith a Weston. in brightness units of the colored    colors, and setting the Normal
 objects in the scene. This con-   Arrow midway on the calculator       Let's zlssunle a seene in
 trast rang:e is designated on the    dial between the trn'o values"                                  fContinued on ofAer srde)

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                                                                          FIG.2                       FIG.3


                                         UNDER-EXPOSED                              OVER-EXPOSED
                                                                                                                                                                                                                             \,                                                              A+-**I              RA.\GE_- ---
                                             UND ER-EXPOSED
                                                                             4:lI
                                         FILM RANGE-G            OVER * EXPOSE D
                                                                   FIG. 4

     which five chief elements have    case), place the C position of the    jects cannot be reached for close-
                                                                                                   nearer     the following readings: girl's   Weston dial at the brightest   up readihgs, substitute a
      jacket 25, scarf 50, hair 100,    value ; in this illustration, 400.    object of similar material and
       flesh tones 200, skY 400 . . . an    Norn' everything down to the A    identical lighting.
      extreme range of 16 :1. What can   position will be reproduced cor-                                                                                                     Errors in Equipment     be done ? ObviouslY, the 4:l  ac-    rectly, and only those less im-
                                                                            Sometimes the photographer      ceptance range of the color film   portant objects with lower
      cannot cover the entire scene    brightness values will be sacri-   has been scrupulously observing
       brightness rangrt. All the film can    ficed by underexposure. This is    all of the above points, and yet
       possibly take is 25 to 1Q0, 50 to   diagramed at B, Fig. 4, and the   he is consistently over- or under-
      200, or 100 to 400.                  setting shown on the dial, Fig. 2.    exposing. This is probably due to                                                                               errors in his photographic equip-                                        3. However, if the lou'           1. The A and C Positiolls,                                     ment. There may be slight errors
      representing the 4:L ratio, can    hrightnes,s objects are the most     in the shutter, errors in the f/stop
     be centered on the 50 and 200    important, place the A position    calibrations, or abnormal losses
      readings respecti'*'elr,'" I{ow all    on the Weston dial at the reading   by lens absorption. When more                                         of the darkest object; in this il-       objects u'ith readings lower than                                    than one of these errors is pres-                                           lustration, 25. No w everything    50 will be underexPosed and                                            ent, they sometimes happily can-                                  up to the C'' position will repro-                                                                                          ezrch other out, in which case        dar"k ; those higher than 200 will                                             cel                                        duce correctly, and only the high-        he. ove.rexnosed. a::1 Pale" This is                                         thr photographer rray L')t realize                                              iights ztbt.,r'e this. whicir  "1't., ti nr)\\,     thzrt alt"\'Lliing is wr'ong.      diagramed at A, -{"ig. 4, .and the                              deem less interesting, will be-       setting shown on the dial, Fig. 1.                                                         If  they do not, an easy                                   come paler by overexposure. This                                                                                compensation is  b)'     But this is the way a general     is diagramed at C, Fig. 4, and the   method of      scene r,vould be treated, in u'hich                                 changing the film rating em-                                            setting shown on the dial, Fig. 3.      the objects of greatest interest                                   ployed. If  the transparencies                                                                   readings   are consistently underexposed,      are probably in the middle part       In taking meter                                from the camera positior, tilt   he should lou,'er the film rating      of the brightness rang:e.                                     the meter toward a point half-    accordingly; if  the.y aye over-
          2. If the most interesting   way between the horizon and    exposed, raise the film rating. If
      features of the scene are the   your feet, to avoid inflating the   they are correct, he is among
                                             (             as is  usuall.y the    readings bln sk)' light. When ob-   the maj ority  !     highlights

                                 THIS IS THE FOURTH IN A SERIE5 OF EDUCATIONAL  ARTICLES ON THE USE OF
                                           WESTON PHOTOGRAPH IC PRODUCTS

              WESTON ETECTRICAT INSTRUMENT CORPORATIOT\E
                                NewcrE k 5, New Jensey,  u" s. A"
                                                                                Printed in U. S. A"





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