|
|
 | | Author | |
|
| | Date | |
|
|
|
|
Jorge Gasteazoro |
19:37 15 Mar 06 |
  |
Your enlarger timer does not have to be too accurate as long as the deviation is consistent. This is why Phil recommends you first calibrate your system before you do the testing.
For example, you expose your film with an EV reading of 4 off the board and you find out your PSP falls at 2.5 instead of 2.4, well then you know your system is over exposing by 1/2 stop. You expose another set of negatives with an EV reading off 3.5 and if your timer is consistent on the error then when you plot your curves your PSP should fall at 2.4.
The film on the holder method is a PITA (tried just for kicks). First, sandwiching the film and step tablet in the holder is tough. Second, is the wall evenly and consistently lighted? A 1/3 of a stop fall off in the wall will give you inaccurate results. Third, do you know your apertures are calibrated correctly? sometimes f/16 is not really f/16 but can be lower or higher than the number on the scale.
I found Phil's method far easier and consistent doing it in the darkroom. Remember, if it aint broke dont fix it... 
|
|
|
|
|
|
|
|
|
R Foley |
5:29 14 Mar 06 |
|
|
Phil Davis |
8:26 14 Mar 06 |
|
|
R Foley |
10:52 14 Mar 06 |
|
|
R Foley |
19:22 15 Mar 06 |
|
|
Phil Davis |
11:46 16 Mar 06 |
|
|
R Foley |
11:51 16 Mar 06 |
|
|
R Foley |
15:34 23 Mar 06 |
|
|
Phil Davis |
18:08 23 Mar 06 |
|
|
R Foley |
18:40 23 Mar 06 |
|
