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 12:48:36 2004
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