I am resurrecting a discussion started here: Platen: Glass or plastic, hoping to give people better guidance on which material to use for their platen. Here's what I have gathered from reviewing this forum:
Using glass:
Pros: 1) clearer; 2) less flexible; 3) more scratch-resistant
Cons: 1) easier to break; 2) heavier
Using acrylic:
Pros: 1) difficult to break; 2) lighter; 3) can be bent using heat
Cons: 1) more flexible; 2) less clear; 3) less scratch-resistant
I am not sure for which of the two choices is reflectivity a greater problem.
To me, the debate rests on the answer to this question: just how important is the quality of the images taken by the camera(s)?
Glass would seem to yield flatter pages and clearer images, thereby making processing a simpler matter. However, it may not be as easy to secure. Yet many contributors have worked with glass successfully. In the post linked to above, Ryan_phx reports success in using outdoor mounting tape and steve1066d reports success using epoxy and Drake Ravensmith's build uses mending plates, corner braces and two threaded rods. However, those who have used glass in their platens suggest offsetting the platen's relative heaviness with a counterweight.
Acrylic seems fairly easy to work with. daniel_reetz's New Standard Scanner shows how to secure acrylic with screws, and rob showed beautifully in Rob's inverted platen build how to bend acrylic to create a V-shaped platen (also achieved by spamsickle in Portable Tabletop Scanner). Yet there has been the occasional complaint that the plastic is prone to some bending, which presumably might yield images of pages that are slightly curved.
Although we all would be fascinated by a method to "de-curve" pages images (see Methods To Sense The 3D Surface/Structure Of A Book), I am not expecting the solution to be inexpensive or easy.
But again, it all comes down to: how important is it that your images be clear and flat? My understanding is that, at this time, keystoning can be corrected by software, but curves or wiggles cannot. Is acrylic really so cloudy that it detracts from one's images? Has anyone scratched her acrylic platen so badly that it has marred her images? Has anyone broken his glass platen during construction or regular bookscanning? Has anyone used museum-quality glass or acrylic (or other plastic) and found it to be "worth it"?
Please weigh in.
Debate: glass vs. acrylic (Plexiglass)
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Re: Debate: glass vs. acrylic (Plexiglass)
Really appreciate these summary posts. I'll address the material questions but come back to the "image quality" question when I have a bit more time.
Short answer:
Acrylic: I believe acrylic is more than "good enough" for people with limited access to equipment/tools, and/or people who only want to scan a couple books.
Glass: I believe glass is stronger, easier to clean, and more durable, but the cost is that it is more expensive, harder to source, and harder to handle (all one-time costs).
Acrylic Pros:
Clear enough (as clear as glass, in fact)
Easier to cut/handle
Easier to mount (not always...)
Cheap/readily available
Unlikely to shatter
Acrylic Cons:
Develops static charge/attracts dust
Very easy to scratch
Thin types are prone to flexing
Glass Pros:
Clear enough (super-clear if it is antireflection coated, but this is very expensive and best for pro-level scanning).
Stiffer than acrylic for a given thickness (and thinner is generally more desirable)
Inexpensive (depends).
The basic rule of thumb is "garbage in, garbage out" though Scan Tailor might fool you on that one. The larger debate on image quality almost deserves it's own thread. I have a lot to say on the matter.
Short answer:
Acrylic: I believe acrylic is more than "good enough" for people with limited access to equipment/tools, and/or people who only want to scan a couple books.
Glass: I believe glass is stronger, easier to clean, and more durable, but the cost is that it is more expensive, harder to source, and harder to handle (all one-time costs).
Acrylic Pros:
Clear enough (as clear as glass, in fact)
Easier to cut/handle
Easier to mount (not always...)
Cheap/readily available
Unlikely to shatter
Acrylic Cons:
Develops static charge/attracts dust
Very easy to scratch
Thin types are prone to flexing
Glass Pros:
Clear enough (super-clear if it is antireflection coated, but this is very expensive and best for pro-level scanning).
Stiffer than acrylic for a given thickness (and thinner is generally more desirable)
Inexpensive (depends).
The basic rule of thumb is "garbage in, garbage out" though Scan Tailor might fool you on that one. The larger debate on image quality almost deserves it's own thread. I have a lot to say on the matter.