From: mwandel@bnr-rsc.UUCP (Markus Wandel)
Date: 1 Jul 91 13:35:58 GMT

This info was in the June 1983 issue of "Modern Photography", page 8.  Because
I'm such a nice guy (and because the question will doubtlessly come up again
and again), I'll type it all in.  First, here is the film cartridge:

              =========================  <-- Light trap
              +---+---+---+---+---+---+
            +-| 1 | 2 | 3 | 4 | 5 | 6 |
Bottom -->  | +---+---+---+---+---+---+
            |_| 7 | 8 | 9 | 10| 11| 12|
              +---+---+---+---+---+---+
              -------------------------

The DX coding surface is divided up into 12 squares as shown.  Squares 1 and
7 are ground, i.e. they are always bare metal.  The remaining squares are
encoded as follows ("*" means bare metal, otherwise square has nonconductive
paint):

FILM                   FILM                EXPOSURE
SPEED  2 3 4 5 6       LENGTH  8 9 10      LATITUDE   11 12
----------------       --------------      ----------------
  25         *          12     *           +/- 1/2
  32           *        20       *         +/- 1      *
  40         * *        24     * *         +2/-1         *
  50   *     *          36         *       +3/-1      *  *
  64   *       *         -     *   *
  80   *     * *         -       * *
 100     *   *          72     * * *
 125     *     *
 160     *   * * 
 200   * *   *
 250   * *     *
 320   * *   * *
 400       * *
 500       *   *
 640       * * *
 800   *   * *
1000   *   *   *
1250   *   * * *
1600     * * *
2000     * *   *
2500     * * * *
3200   * * * *
4000   * * *   *
5000   * * * * *

Enjoy!

Markus Wandel