FotoDave@aol.com
Thu, 21 Jan 1999 13:12:31 -0500 (EST)
In a message dated 1/21/99 2:12:46 AM Pacific Standard Time,
rwsalles@provida.org.br writes:
> Considering a normal development, what step in the T-14 corresponds to a
> neutral 18 %gray card ?
I am not sure if you are asking the density of a gray card, or if you are
asking what the density of the film should be if you shoot a gray card with
exposure metered with the gay card (for zone system calibration). I believe it
is the latter. Since this is not directly related to alt. process, I will
answer briefly. Feel free to contact me offlist if you have more questions.
For zone calibration, you need to find not just the development to produce the
right density, but also the system speed. In brief, the following is the aim:
gray card minus 4 stops (underexposed) should give 0.1 + base+fog
gray card plus 2 stops (overexposed) should give approx. 1.05 + base + fog
base+fog is different from film to film, so make sure you account for that.
For example, b+f of TMax100 roll film is about 0.24.
You can then compare your target value with a step tablet. Cor has listed the
densities of the steps, so I won't repeat.
Dave
This archive was generated by hypermail 2.0b3 on Sat Nov 06 1999 - 10:06:43