Re: Strange Thing with Step Wedge

Richard Sullivan (richsul@roadrunner.com)
Fri, 25 Jul 1997 09:23:49 -0600

>Date: Thu, 24 Jul 1997 17:56:48 +0100
>From: Pascal MIELE <pascal.miele@wanadoo.fr>
>Subject: Re: Strange Thing with Step Wedge
>X-Sender: pascal.miele@smtp.wanadoo.fr
>To: Alt-Photo <alt-photo-process-l@skyway.usask.ca>
>Comments: "alt-photo-process mailing list"
>
>>I tried to make an enlarged step wedge from my Stouffer step wedge so that I
>>can measure the density in the final print because the original is very
>>small. It was a 35mm steps, and I enlarged it to 4x5. I found that the steps
>>go darker and darker (as expected) and then start to turn lighter from
step 6
>>to step 2. Then step 1 gets darkest (as expected).

My old buddy Jack MacDonald used to make step wedges, but he made them one
step at a time on an 8x10 piece of film. Trying to make all the steps at
once puts you into a situation where the curve of the materials and
chemistry of the production process alters the steps. I helped him makes
some once, but it has been close to 30 years so I am a little dim on it. I
also remember that he made liberal use of Farmers reducer to downward
adjust the values of each piece.

He would make 8x10's to the specific value. It's easy to make a .60 density
8x10, but harder to get it even throughout the neg. I believe Jack only
used the central portion. He would then cut up the negs and assemble them
into wedges of 9 steps. I dont't recall how he assembled them but I imagine
one could with a little ingenuity, cut each 8x10 into strips and edge glue
the strips with Superglue and then cut those into wedges. Jack used to sell
these at TriMac Photographic in Inglewood Ca. back in the early 70's.

Of course this method is only good for making them in quantity. At about 10
bucks per, It doesn't make much sense to do it this way unless you want to
share them with list members or sumthin like that.

Dick
Bostick & Sullivan
PO Box 16639, Santa Fe
NM 87506
505-474-0890 FAX 505-474-2857
http://www.bostick-sullivan.com