Large format "scanning" setup

[adamhiram]

I have used this large format "scanning" setup sporadically for a few years now, based on the "standard copy setup" in chapter 4 of Light: Science and Magic. The copy surface is a piece of plywood to keep it flat, the document to be scanned, and a piece of plate glass over it to press it flat. Lighting is from a pair of large double-diffused square softboxes fired at equal power and metered to match the lens's aperture (usually f/5.6 or f/8).

This has worked well for me, except I've always scanned old documents I wanted to digitize or the occasional photo print, where I didn't notice anything strange. Then I recently went to scan a darker photo and realized a big problem with this setup - even though the lights are at 45 degree angles, the camera (and my arm) are reflected in the glass. There must be a way around this, but I have yet to figure it out.

Hopefully someone here can provide some suggestions on how to eliminate this reflection.

Some thoughts I had:

• Change my setup - perhaps flag the light on either side of the camera, or raise the camera above the height of the softboxes to prevent it from being illuminated. Here, I run into issues with extending the tripod arm horizontally too far and have stability issues that would likely require additional gear.
• Should I be using a different type of glass, such as something with an anti-reflective coating? Right now I'm using a cheap piece of plate glass from the hardware store.
• Perhaps a circular polarizer on the lens would be an easy fix? I've been looking for an excuse to pick one up, so this could be an option as well.

Thanks in advance for any advice! This seems like a fairly standard setup, so hopefully there's something simply I'm overlooking.

Here is the setup I use:

20200525-DSC_9601a by adamhiram, on Flickr

Here are some sample shots with a random inspection sticker from my tripod on some standard printer paper and on a piece of black construction paper. For the last shot, please ignore the dust I neglected to clean the dust off of the glass.

This is what it looks like when I scan a brighter document - no observable issues:

20200525-DSC_9588a by adamhiram, on Flickr

Here is where the reflections become noticeable:

20200525-DSC_9589a by adamhiram, on Flickr

 

[480sparky]

Polarizers on both the lighting and the lens can eliminate most of the reflections.

A remote release will easily remove your arm's reflection.

 

[Derrel]

Shoot through a lens-diameter hole cut in a black sheet of posterboard or similar. It might be easier if the setup were wall- mounted instead of floor-mounted.

 

[JBPhotog]

This is a job for black duvetyne, velvet or felt, what ever your local fabric store sells. Felt usually comes in double widths @60” so it gives you great coverage for blacking out a set. I prefer it to black foamcore even though foamcore is flat black, if it is close to the incident angle of your lights it can reflect back into the lens axis due to light spilling from your flashes.

Draping it over your lights and around your lens by way of a hole cut into the fabric should do the trick. Small clamps can help keeping things tight and unobstructing your view of the subject.

 

[adamhiram]

Polarizers on both the lighting and the lens can eliminate most of the reflections.

That definitely makes sense, although it sounds more complicated than this needs to be, and involves materials I don't have readily available. Any thoughts on whether a circular polarizer would do anything on its own, or if it really requires the light source to be explicitly polarized to be effective?

A remote release will easily remove your arm's reflection.

Of course! I think the other recommended solutions will address this as well.

Shoot through a lens-diameter hole cut in a black sheet of posterboard or similar.

I think this will be my preferred solution. If I raise the camera about a foot, it should at least remove the direct lighting on the equipment from the softboxes. From there, I have a roll of black seamless paper I can stretch across and cut a hole in the center for the lens, with the lens hood holding it up. Thanks for the great idea!

It might be easier if the setup were wall- mounted instead of floor-mounted.

Agreed. If I was making a living doing this it would be a no-brainer; I could probably even use a crossbar with a super clamp mounted in the middle, using existing gear.

Draping it over your lights and around your lens by way of a hole cut into the fabric should do the trick.

I think this is my path forward, except using black seamless since that's what I have available. Thanks for the great advice!

 

[smoke665]

Any thoughts on whether a circular polarizer would do anything on its own, or if it really requires the light source to be explicitly polarized to be effective?

At least you have a set up, I've been known to tape a negative to the solid glass storm door to copy. LOL

Cross polarization uses a linear polarizing film on the light source and a circular polarizer on the camera. When rotated such that the lines in the two are perpendicular to each other they cancel out reflection. In a pinch the polarizing lens from sunglasses, will work on a speed light, or using a laptop monitor as your light it's polarized already.

 

[Derrel]

I used to make some money doing copy work back in the 1980s, before home computers and scanners were even " a thing"...

 

[petrochemist]

Move the lights in & down to the point they no longer shine on you & the camera (or raise the camera). This will probably be enough

 

[adamhiram]

Move the lights in & down to the point they no longer shine on you & the camera (or raise the camera). This will probably be enough

Thank you, I think you're probably right. I'll give this a try before cutting up my roll of black seamless. Either way, sounds like an easy enough fix!

 

[JBPhotog]

Alternatively you can get some black gaffer, masking tape or hockey tape and apply it to the subject side shiny bits on your tripod and camera so they don’t reflect back into the glass.

 

[adamhiram]

I finally got some time to work on this setup to try to reduce reflections and improve my results with darker images. Please pardon the lengthy post, I always like to include thorough follow-up when I can. The differences between the examples below are very subtle, but keep in mind that's the whole point. As a reminder, the test image is just a sheet of black construction paper with an inspection tag in the center to give me something to focus on. Thanks for all the great feedback!

Move the lights in & down to the point they no longer shine on you & the camera (or raise the camera). This will probably be enough

This was the first step I tried. I initially used shorter light stands but it made accessing the media I was photographing difficult. Instead, I raised the camera up higher so the lights would not illuminate the camera or tripod. This meant the horizontal extension was further out, and necessitated a sandbag on the tripod to keep it stable and from tipping over. Moving the camera out of the light made a huge difference, as you can see below. I can still see the reflection of the tripod head on the bottom of the image, but this got me most of the way there already.


20200703-DSC_0711a by adamhiram, on Flickr

Alternatively you can get some black gaffer, masking tape or hockey tape and apply it to the subject side shiny bits on your tripod and camera so they don’t reflect back into the glass.

I did this next. I opted to use a full sized Black Foamie Thing to cover the tripod extension and head, and it worked like a charm. In most instances, this is probably sufficient.


20200703-DSC_0715a by adamhiram, on Flickr

Shoot through a lens-diameter hole cut in a black sheet of posterboard or similar. It might be easier if the setup were wall- mounted instead of floor-mounted.

I would have thought the prior results were perfect had I had not tried this last step. I rigged something up with some long strips of cardboard to support sheets of black posterboard to block all light from above, and I can definitely see a subtle difference. Comparing the results below with the prior result, I can faintly see the dark outline of the camera visible in the latter. I think this will be my go-to setup, and I will likely just glue some black seamless paper onto a large sheet of cardboard with a hole cutout for the camera lens for future copy work.


20200703-DSC_0714a by adamhiram, on Flickr

Lastly, here is the modified setup

20200703-DSC_0736a by adamhiram, on Flickr

And how I attached a Black Foamie Thing

20200703-DSC_0761a by adamhiram, on Flickr

Thanks all for the help!

 

[Derrel]

I always admire your thorough testing and applaud your willingness to take suggestions.

 

[adamhiram]

Getting even closer...

I made a large black flag to cover the top by gluing a 30"x54" sheet of black seamless paper to a piece of cardboard and cut a hole in the center to shoot through.


20200716-DSC_0899a by adamhiram, on Flickr

The results looked about as perfect as I could hope for, with absolutely no reflection in the glass.


20200716-DSC_0903a by adamhiram, on Flickr

Or so I thought... I took another test shot with the blue sticker removed, and I can still see a faint dark circle in the middle where the cutout is for the camera lens. You have to stare at it for a moment to see it, but it's definitely there if you look for it.


20200716-DSC_0907a by adamhiram, on Flickr

So that leaves me wondering if this is the best I can do, or if there is a way to improve on this setup. Something tells me at this point that reflection will probably not be noticeable 95% of the time, but I wonder if digitizing something with solid dark colors near the center would still show it.

Some additional thoughts I had on improving this setup:

• Raise the camera higher and use a longer lens - that will get it further away from the light source, and the inverse square law should ensure there is enough falloff to avoid illuminating the black flag or lens. However I already have my tripod height maxed out at about 4.5' and I'm already shooting at 85mm, so I'd be looking at additional equipment and standing on a stool to accomplish this.
• Use the shift part of a tilt-shift lens to move the camera out of frame entirely. This would probably be a decent idea if I had a tilt-shift lens.
• Shoot from an angle to keep the camera's reflection out of frame, then fix the perspective in post. This would be easy enough, and is something I occasionally do with the guided transform tool to fix vertical lines, but it seems like an unnecessary degradation of the image.
• What about using "museum glass" that includes an anti-reflective coating? I have wondered from the start if the main problem wasn't simply that I was using the cheapest possible sheet of glass from the hardware store.

I welcome any additional suggestions or feedback to improve and/or simplify this copy setup. I can't help but feel like I am reinventing the wheel, but I haven't had much luck finding a recipe for a "standard" setup to do this.

 

[Mike Drone]

I could see it easier with peripheral vision and movement. I wonder if I would have notice if we were not told it was there. Awesome research.

 

[JBPhotog]

See post #4. “This is a job for black duvetyne, velvet or felt.”

Seamless paper is reflective due to the smooth surface. Black duvetyne, velvet or felt have properties that reduce the light reflected off them. I have done this many times and paper will not kill reflections.