====== Film Development ======

===== Dimensions =====
Film dimensions
^  Format  ^  Dimension      ^  Surface (per sheet/roll) ^  •    ^      • ^
|  135     |  24mm x 36mm    |  311 cm² (36 exp)      |  1    |  0.67  |
|  120     |  61mm x 760mm   |  464 cm²               |  1.5  |  1     |
|  4x5     |  100mm x 125mm  |  125 cm²               |  0.4  |  0.27  |


===== Rules of thumb =====

==== Exposure Index (vs. SBR)====
The table below suggests how to select film exposure index (relative to box-speed) and adapt film development time (relative to datasheet) given an expected subject brightness range (SBR).[(biblio:Lambrecht2011)]
^  SBR  ^  EI      ^  Time  ^                        ^
|  L    |  -       |  -     | rainy or foggy day     |
|  N    |  -2/3    |  -15%  | bright but cloudy day  |
|  H    |  -1 1/3  |  -30%  | bright sunny day       |

==== Expansion / Contraction (N +/- development) ====
In general, a rule of thumb is to[(biblio:Lambrecht2011)]:
  * increase exposure by 1/3 stop whenever the SBR is increased by one zone (N-1), while decreasing development by 15%.
  * decrease exposure by 1/3 stop whenever the SBR is decreased by one zone (N+1), while increasing development by 25%.

From another source (?), the following reccomendation is given:
The table below suggests how to adjust film development to accomplish N+/- development.
^N-1	| -15% < N-1 < -25% |
^N+1	| +25% < N+1 < +40% |