Stouffer 21 Step Step Wedge

Discussion in 'Talk About Digital Scanning' started by Ian-Barber, Feb 4, 2017.

  1. Ian-Barber

    Ian-Barber Admin Staff Member Registered User

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    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%

    Stouffer-21-Step-Wedge-Linear-copy.jpg
     
  2. Dewi

    Dewi Guest

    Dear Ian,
    Where did you get your step wedge from? In the UK?
     
  3. Ian-Barber

    Ian-Barber Admin Staff Member Registered User

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  4. Dewi

    Dewi Guest

    thanks Ian
     
  5. mpirie

    mpirie Member Registered User

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    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.
     
  6. David M

    David M Well-Known Member Registered User

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    This is interesting. What will the next step be?
     
  7. mpirie

    mpirie Member Registered User

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    For me, just getting round to doing the tests ;)
     
  8. roncromberge

    roncromberge Member Registered User

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    This is not bad at all. I can see on this lowres picture 7 stops. Until step 14.




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