Re: Step Wedge

You can always use the camera in the shade I focus approximately
7 inches from a grey card so the card fills the exposure area.
An overcast day is (Ideal "IMOP") for film testing.

On Nov 10, 2004, at 1:48 PM, Sandy King wrote:

> The Mark Nelson wedges of 31 steps that I have are longer than 5" so
> they would not fit on a piece of 4X5 film. Stouffer makes 4X5 wedges
> with 31 steps if that is what you want.
>
> The problem with generating curves exposing through the camera is
> flare. It varies a lot according to lens, bellows position and
> lighting conditions which would probably result in considerable
> inconsistency in your curves.
>
> Sandy
>
>
>
>
>
>
>> Is the 31-step wedge, mentioned, on a 4x5 piece of substrate? I was
>> thinking sandwiching this in front of film, in my film holder, and
>> exposing in-camera would also serve to help me conduct film tests...
>>
>> BTW, anyone use this method of generating film curves and finding
>> film speeds? I'm assuming that I would be exposing an evenly
>> illuminated
>> surface at zone X? I am a little cloudy on analyzing the results to
>> determine, first of all, my true film speed. I have access to
>> something
>> akin to a densitometer to aid in checking resulting densities...
>>
>>
>>
>> On Mon, Nov 01, 2004 at 09:33:39AM -0500, Sandy King wrote:
>>> If you are using a reflection densitometer to evaluate results make
>>> sure that the width of the steps to be read is not greater than the
>>> reading aperture of your densitometer. I would recommend the
>>> Stouffer TP 4X5 step wedge. It is available in both 21 step and 31
>>> step versions and allows a convenient test of 4X5" (with reading
>>> area
>>> 1/4" wide) to be printed. If the reading aperture of your
>>> densitometer is small enough you could probably make do with the
>>> small and inexpensive Stouffer T2115.
>>>
>>>
>>> BTW, Mark has recently produced in conjunction with Stouffer a
>>> 31-step tablet for precision digital negative calibration and it is
>>> very easy to read.
>>>
>>> Sandy King
>>>
>>>
>>>
>>>
>>> >Hi all,
>>> >
>>> >I am about to purchase my first step wedge for alt-photo. Mark
>>> Nelson's
>>> >book recommends the Kodak or Stouffer wedges. Due to price, I
>>> will be
>>> >buying a Stouffer 21-step wedge but the question is, which one is
>>> correct
>>> >for alt-photo work.
>>> >
>>> >Will the T2115C transmission step wedge be what I need?
>>> >
>>> >Thanks in advance.
>>> >
>>> >Oody
>>> >
>>> >_______________________________________________________________
>>> >When you hold the head of a snake the rest is nothing but rope.
>>> >
>>> >Akan (Ghana) Proverb
>>> >_______________________________________________________________
>>>
>
Received on Wed Nov 10 13:22:55 2004