Oversized davidlandin Model

Built a scanner? Started to build a scanner? Record your progress here. Doesn't need to be a whole scanner - triggers and other parts are fine. Commercial scanners are fine too.

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GPHS2
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Re: Oversized davidlandin Model

Post by GPHS2 »

David, I was thinking the same thing. And I don't want to cut down on lighting but increase it.

Wow, that is interesting about the Plexiglas XT, I didn't know anything like that existed and would be interested to hear how it works if you ever decide to try it. I will see if it is available here in the U.S.

As for using a tent like structure to block out other light, I don't think I will have to worry about that for now. I currently have this unit set up in my computer room in my basement. There is actually only one other light source in that room and that is a small window that I can easily block off while using the scanning unit. So that room is almost the same as having a covering over the unit to block out light. I haven't seen any reflections showing up yet. I did actually look at the wardrobe type coverings you use and have seen them on Ebay, etc. If I find I will need something like that I can even get someone locally to sew a bigger version out of black material and just make the structure out of PVC Pipe to support it. But I think I will be ok until I move the unit to another location.

As luck would have it, our light setup is just about what you mentioned. Only we currently have 2 lights hung above the gutter of the platen. However the bottom of the lights are actually about 29 inches from the center of the platen when it is lowered into the seam of the book we are scanning. I thought about lowering it but fear that will reduce the amount of light that is hitting the sides of the pages. That is where we are currently needing more light. So I hate to lower them yet.

I am really looking for some type of powerful LED lights to more evenly light the areas so when I get to scanning the newspapers I will have enough light to illuminate even the corners. It is just difficult to find certain various types of lights locally so I have to order them off Ebay to try them and then if they don't work I can't just return them to the local store which could end up costing quite a bit until we get it right. I am planning on speaking to a local lighting store owner for their suggestions but they may not have any idea what it is I need. I will show them pictures and explain the process and see what they come up with. It is possible they may even donate the lights or at least let me try them and if they don't work just return them.

David, did you see that link I posted recently about the LED Flat Panel Lights? Ron from our society mentioned those and they looking interesting.

http://forums.azbilliards.com/showthread.php?t=348495

I also saw these on Amazon.

http://www.amazon.com/Lighting-EVER-Pan ... anel+light

Mike
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PossumPete
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Re: Oversized davidlandin Model

Post by PossumPete »

What a wonderful project!
I grew up not all that far from you, up in Tioga county.
We had a Pittston wood cookstove for many years. :D
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Re: Oversized davidlandin Model

Post by davidlandin »

Hi Mike

I've just taken a couple of shots of the same bit of newspaper first using the shiny (regular) side of the acrylic i.e. the back of the sheet, and then using the front side which has this ?spray on? anti reflective coating. There is a huge difference in reflectivity. I just peeled back the protective polythene sheet on both sides of the acrylic to try it
Coated side up
Coated side up
Shine (normal) level of reflection
Shine (normal) level of reflection
This coated plexiglas is made in Sweden I think, but I have read other posts where people have written on this forum about museum glass, and they talkad about a crafts store chain where you could get it. So it might be worth a try.

I haven't looked at these bright floodlight type LED lights, but I want to. I wonder if you could mount two back to back, with one pointing at the left page and the other at the right. They do seem very bright

David
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Re: Oversized davidlandin Model

Post by davidlandin »

You need to check the captions on the photos - the worse image is the uncoated one, and that comes second.
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Re: Oversized davidlandin Model

Post by dpc »

A more fair comparison would be to have the light source and camera position/settings to be identical between the two photos with only the acrylic changing between the two photos.

I'm of the belief that reflections should be eliminated by proper scanner design (position of the camera and light source) and eliminating extraneous light sources and reflections off the scanner components when scanning. Realize that even if you're able to mitigate the reflection back to the camera lens by using special coatings, you still have hot spots of light hitting the page at that point that may result in uneven light across the page. For example, imagine that you had a book with pages that would lie perfectly flat in your scanner and you didn't need to use a platen. You're not going to get the typical specular reflection back into the camera lens as you would with a platen glass over the page, but you will get a diffuse reflection off of the page which will appear as uneven lighting or a hot spot.

There's also the possibility that the coating on the platen could affect color/sharpness of the image, and on acrylic there's the chance that this coating could be diminished over time from cleaning.
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Re: Oversized davidlandin Model

Post by GPHS2 »

PossumPete wrote:What a wonderful project!
I grew up not all that far from you, up in Tioga county.
We had a Pittston wood cookstove for many years. :D
Yes, you were almost a neighbor then. (:-)

The Pittston Stoves were the best. We had one when I was growing up and we loved it.

Now guys use them for heating hunting cabins a lot.
GPHS2
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Re: Oversized davidlandin Model

Post by GPHS2 »

Dave, that looks pretty impressive. I have to find out where to get them locally. It certainly can't hurt. But I agree that I still need a better light source.

I am currently getting ready to go on a road trip with my wife. We do one or two every year. Last year we did one in late May into June and we drove 8,613 miles across the country. Then in October we did one from Penna. up to Maine, New Hamshire and Vermont. The year before that we did one 9,973 miles. We love the road trips.

The reason I mention this is that we will be leaving the 22nd of March this year so that is just 8 days away. I won't be able to answer any posts here for a few weeks until we get back unless I have time in the hotel. We are also taking a cruise out of New Orleans so then I will be out of contact for a week.

I think I am going to scan a few books just to see if anyone has any problems transcribing them. If that works I can get some scanned and then work on the lighting when I get back. These are going to take a very long time to transcribe as some of the ledgers have 600 pages of hand written text. (:-)

I took the unit apart Wednesday evening and took it to the historical society meeting so the members and visitors could see what we were working on. The local newspaper sent a photographer and writer there to write a story about the project. Ron is hoping the publicity will get a few local people to volunteer to help us transcribe the ledgers. It is a lot of work and will take a lot of volunteers for sure. If it weren't for this group I doubt if we would have undertaken this project so we owe you all a big Thank You.

Mike and Ron
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Re: Oversized davidlandin Model

Post by GPHS2 »

DPC is right. And I know David knows that too. I think he just wanted us to get an idea of the difference. Once he gets it set up I am sure he will post better examples.

Speaking of cleaning the plexiglas, I am curious what others use to clean it. Any suggestions?

Mike
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Re: Oversized davidlandin Model

Post by cday »

davidlandin wrote: I've looked at anti-reflective stick-on stuff, and have wondered about polarised plastic or coating. I thought maybe some "frosted" adhesive film might be OK, but the frosting cut down massively on the quality of the letters of the text. they were much more blurry.

However, I am now looking at Plexiglas XT which we can get in the Uk quite cheaply, and it does have a much lower level of reflection. Here is a link
http://www.cutplasticsheeting.co.uk/cle ... ve-acrylic
Tracing this anti-reflective Plexiglas back to the manufacturer's data sheet -- not entirely straightforward -- it looks as if 'Plexiglas XT' is actually the designation for a wide range of Plexiglas products, the 'XT' simply standing for 'extruded' as opposed to cast.

The full designation for the anti-reflective variant seems to be Plexiglas Gallery UV100 AR so anyone looking to source some should ensure that they are ordering that version. There are also anti-static (suffix AS) and anti-mar (suffix MR) versions available.
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Re: Oversized davidlandin Model

Post by davidlandin »

I think it definitely more than just extruded. There is a special coating which is applied to one side of the acrylic. See this quote for a description:

"Anti Reflective Acrylic
PlexiGlas XT gallery standard anti-reflective acrylic (also known as Perspex). A highly transparent material with non-glare surface on one side which also absorbs destructive UV light. Non-reflective acrylic is ideal for use in galleries and exhibitions where the strong lighting can often cause irritating glare which detracts from the viewing experience.

Plexiglas Gallery Anti-Reflective Acrylic has set a new standard for artwork protection and reflects up to 99.7% of UV light. Plexiglas XT Gallery anti-reflective/anti-glare acrylic offers much more protection compared with conventional picture glass (float glass).

This material has a finished surface that restricts the reflective qualities often found with gloss acrylics. It is ideal for glazing where the image is in close contact with the anti reflective acrylic. If there is no contact with the surface of the material, the image will have a frosted distorted look.
"

However I take your point that if people are looking for this material they should be focus on the "anti-reflective" rather than the XT, which may result in getting the shiny stuff

That last phrase is a bit worrying, but I haven't noticed any distortion. My slight worry is because although the shiny side of the plastic is in direct contact with the book, there is a 3mm distance between the non-reflective upper surface and the paper itself (the thickness of the acrylic). I don't think this will really make any significant difference to the quality of the image, and the reflections are likely to to be more of a problem, which this kind of plastic does help to cure.
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