Stouffer 21 Step Step Wedge


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Registered User
I am conducting some tests with the Epson V800 scanner to see if I can ascertain it's minimum and maximum values in which it can resolve information from a black and white negative.

The following is a low resolution version of the scanned step wedge which I scanned as a linear file (gamma 1.0) in VueScan and then converted it to gamma 2.2 for viewing.

Each step of the step wedge represent 1/2 a stop and as far as I can make out, I can see tonality from step 2 up to and including step 16 which indicate that the scanner can extract an 8 stop range.

The first step is film base which has a K value measured in Photoshop of 97% and step 16 has a K value of 8%



Dear Ian,
Where did you get your step wedge from? In the UK?


Registered User
I picked up a 21 step 5x4 version several years ago and intend to start testing film with it contacted together in a DDS......just need to get round to it.

Need to dig out the densitometer too!

PS there is a 31 step version that gives 1/3 stops instead of the 1/2 stops on the 21 step wedge.