# Step Wedge?



## J.R. (Sep 3, 2014)

I'm back on CR after a reasonably long gap. I was going through some posts and came across "step wedge", an animal new to me. 

Ok, now leaving mirth aside, can anyone explain what is a step wedge and what is it used for? 

Thanks in advance ... J.R.


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## neuroanatomist (Sep 3, 2014)

http://www.stouffer.net/TransPage.htm


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## Mt Spokane Photography (Sep 3, 2014)

I was going to refer you to Neuro, but he picked up on this first.


Apparently, you can generate one in Photoshop and use it to adjust images? I did not read the many articles about doing this, since I adjust images to suit my eyeball rather than be technically perfect.


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## mackguyver (Sep 3, 2014)

Mt Spokane Photography said:


> I was going to refer you to Neuro, but he picked up on this first.
> 
> 
> Apparently, you can generate one in Photoshop and use it to adjust images? I did not read the many articles about doing this, since I adjust images to suit my eyeball rather than be technically perfect.


I don't really understand why you would need one in the post-film days, but maybe I'm misguided. My only experience with them was using a test pattern to verify that my 10-bit (per channel) / 30-bit monitor was getting a true 30-bit signal from the OS / Software / Video card combination. It was expensive and painful to get it all to work together but when the gradients finally blended seamlessly without any steps, it was a good day . I'm not sure if I can tell any difference between 16.7 million and 1.06 billion colors, though


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## DominoDude (Sep 3, 2014)

Mt Spokane Photography said:


> I was going to refer you to Neuro, but he picked up on this first.
> 
> 
> Apparently, you can generate one in Photoshop and use it to adjust images? I did not read the many articles about doing this, since I adjust images to suit my eyeball rather than be technically perfect.


Like this --> http://www.jnevins.com/stepwedge.htm


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## Logan (Sep 4, 2014)

what do you use your densiometer for?


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## neuroanatomist (Sep 4, 2014)

Logan said:


> what do you use your densiometer for?



I use one for quantifying data (usually autoradiograms) on X-ray film.


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## Logan (Sep 4, 2014)

cool. do you ever get a chance to do artistic x-ray stuff? I saw some really neat ones of natural objects like flowers and shells. 

i looked at the step wedges for photography use and its not just you mackguyver, i cant see a use for it with digital either, unless you are doing scientific work of some kind.


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## J.R. (Sep 8, 2014)

Thanks for the replies. Having read about them, I'm not entirely sure where they figure in digital photography. In case anyone has found any use for them in digital photography, please share your experience.

Regards,
J.R.


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## neuroanatomist (Sep 8, 2014)

Logan said:


> cool. do you ever get a chance to do artistic x-ray stuff? I saw some really neat ones of natural objects like flowers and shells.
> 
> i looked at the step wedges for photography use and its not just you mackguyver, i cant see a use for it with digital either, unless you are doing scientific work of some kind.



Sadly, no fun X-ray stuff. 

The only use for a step wedge in digital is empirically testing the DR of your camera.


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## J.R. (Sep 8, 2014)

neuroanatomist said:


> The only use for a step wedge in digital is empirically testing the DR of your camera.



Ugh ... Us Canon shooters don't need one, we are well aware that the DR of our cameras suck! :-X


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## Tsuru (Sep 8, 2014)

I've still got my step wedges from my days of calibrating digital dental radiography equipment. The joys of securing a 4" long step wedge to the panoramic emitter with electrician's tape. :
Since most dental offices needed a pre-set exposure, both the emitter and the digital developer (really just a fancy laser assembly with a very sensitive stepper motor) required to be calibrated together. Not exactly scientific research but a digital application for step wedges.


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## Logan (Sep 10, 2014)

so in x-ray you use it to set the exposure, basically a grey card for light levels instead of colour levels?


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## Jim Saunders (Sep 10, 2014)

Logan said:


> so in x-ray you use it to set the exposure, basically a grey card for light levels instead of colour levels?



One thing you can do is shoot one at defined settings to check that your complete system (from the x-ray source to the developed film) works properly. Where you go from there depends on what you're shooting; if it isn't a new job someone has probably written down good settings.

Jim


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## pwp (Sep 10, 2014)

neuroanatomist said:


> Logan said:
> 
> 
> > cool. do you ever get a chance to do artistic x-ray stuff? I saw some really neat ones of natural objects like flowers and shells.
> ...


I saw some fantastic editorial images of a hand holding a handgun. In x-ray it looked extraordinary, and especially powerful in the context of the article which dealt with the insanity of gun ownership statistics and laws in the US. 

Here's the startling statistic. 50% of the guns on Earth are owned by Americans, yet the US has just 5% of the worlds population. Can you believe that? For a nation of such smart people, it's a breathtaking, indefensible & totally bonkers blind-spot. Trade them in for cameras!

-pw


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