How to scan fragile old blueprints?

[OldGeezer]

I couldn't figure out where the best section was to post this, so I hope this is appropriate. When you have original blueprints for WW2 aircraft and want to make digital copies, what's the best way to go about it? These things have been kept folded for 75 years and not only are there stubborn fold lines when you open them out, but the paper itself feels dry and fragile. Not the sort of thing I'd trust the local Kinkos to feed into the rollers of their scanners, but I'm at a loss to think of an alternative. I don't know anyplace with a flatbed scanner big enough to take one of these (roughly 3' x 5' or more, i.e. roughly 1m x 1.5m.) We had thought we'd just scan sections and digitally combine them but we weren't able to get our small home scanner to accommodate the extra paper all around the areas away from the outer border without risking damage to the paper. I'm thinking the best way might be to build a duplicating rig, a sheet of something flat like drywall on the floor with a large piece of window glass or acrylic to put over the blueprint and gently encourage it to lie as flat as possible. Then shoot each section separately with a fairly long lens to reduce perspective problems and stitch the frames together in Photoshop. Has anybody else dealt with this problem though? We're only going to get one shot at this, the blueprints are in a collection whose owner is the son of the original designer, and while he's happy to bring them over, he won't leave them with us.

 

[swampyankee]

Call a local university archivist. They may know some services, which are unlikely to be cheap.

 

[Crimea_River]

I did have a fragile, 65 year old 36 x 48" blueline print that I had done at the local Michael's. The did a pretty good job and did not damage the original. The scanned dark fold lines were then removed with about 20 hours of photoshop work.

 

[special ed]

Consider microfilm. It's old school but many universities still use it. Old news papers are more fragile than blue prints.

 

[MiTasol]

Contact Ester at [email protected].
She is doing this sort of work all the time. I have dealt with her on other matters and found her to be extremely helpful.
Her video at Ken Jungeberg Collection | AirCorps Library may give you some clues.

I always scan in colour (TIFF) and for editing out the yellow/brown background and fold lines I use Irfanview. Always remove the background colour first - you will be surprised how often the fold line goes as well. Irfanview is free and has 1/10 the learning curve of Photoshop though only 20% of the functionality. For example I assembled a shortcut (Control-Alt-C) that takes out the background colour in one or two passes. Also get the shortcuts as that is virtually the only support but the program is so simple that they are really all you need. http://www.kiwimodeller.com/~kmodel/media/kunena/attachments/809/irfanview_basics.pdf covers the very basics and each of the following expands on it (with some duplication). 120 Shortcuts for IrfanView 4.42 and https://defkey.com/irfanview-shortcuts and Irfan View keyboard shortcuts and SOFTWARE TRICKS: List of IrfanView Shortcuts

According to some sources at the time Shrek 1 was done in Irfanview with private add-ons though I have my doubts.

Another free option is GIMP - it has things Photoshop lacks and vice-versa and has very good support from the user groups, and, depending on where in the world you are the answers can arrive in minutes.

If you have any problems using Irfanview to do the background and fold lines PM me and I will walk you through creating the shortcut (I will need to work it out again as I did it years ago).

 

[GrauGeist]

As an option, contact your local university, as many have vintage map archives and the ability to scan vintage maps such as the old USGS survey maps, which were fairly large.

 

[Shinpachi]

In my case, I simply took a dozen of pictures for a sheet of drawings, totally and partially, as I was going to leave them as CAD data finally.

 

[MiTasol]

You have a good point there too - as photos photo stitching software will join the photo parts in many cases. I have yet to find stitching software that works with scans though I have to admit I have not looked for maybe a year or more since I worked out how to do it in Irfanview.
The down side of photos is that many cameras cause barreling and if the camera is not perfectly square to the object then key-stoning is an additional problem. Many years ago a company I visited regularly placed the blueprints under glass as Oldgeezer suggests and then photographed them from about 3 metres above using a special extra fine grain microfilm in a 35mm camera. I was one of many who used the same microfilm for some photography and they did all my developing and printing. I doubt that such tech even exists outside museums now.

 

[OldGeezer]

...Another free option is GIMP - it has things Photoshop lacks and vice-versa and has very good support from the user groups, and, depending on where in the world you are the answers can arrive in minutes....

GIMP has always been my go-to graphics program, but their latest version has gotten so different from the ones that I'm used to, as far as how it handles layers and pasting and how you can work with things, that I actually uninstalled it and reinstalled version 6, I think it was. Even then I lost functionality; the brush selections aren't as varied as they used to be, and some of the ones I used the most just aren't there now. But I'm slowly getting used to it. My wife has the full-blown Photoshop on her computer in case we need that. My current problem, though, isn't so much the handling of the graphics, it's the hardware that I need to get the unfolded J- and K-size blueprints into digital form in the first place. We tried simple photography but the perspective distortions were just too bad, even when we went by small sections rather than trying to do the whole thing at once. I think what we're going to try next is putting a sheet of drywall on the floor, unfolding the drawings on that, and then laying a piece of clear acrylic or window glass over the top so that the weight gently presses the paper as flat as we can get it. That still leaves the perspective problems but at least it removes one of the big issues first. My wife had the idea of putting reference dots on the glass to act as indicators for correcting photographic distortions, and that sounded like a promising thought. It'll be May before we have access to the drawings again, so we have some time to figure this out. Maybe I'll buy some random old folded blueprint on eBay to experiment with, so we don't damage the literally irreplaceable ones we ultimately want to digitize. Thanks for all the great inputs folks!

 

[OldGeezer]

In my case, I simply took a dozen of pictures for a sheet of drawings, totally and partially, as I was going to leave them as CAD data finally.

If we can get ours to lay flat, that's what we'll do. I think Photoshop has a built-in function that lets you specify what camera/lens you used to take the photo, the most common ones anyway, and it has some sort of auto-adjust feature. I think. My wife is the Photoshop guru, I'm more of a GIMP user myself. But it's encouraging to see this - thanks!

 

[OldGeezer]

As an option, contact your local university, as many have vintage map archives and the ability to scan vintage maps such as the old USGS survey maps, which were fairly large.

I thought about our local art museum, it's world-class so you'd think they'd have people on staff who would be familiar with documenting large things. But I don't see any such department on their website. We have, about 5 miles from our house, a branch of the National Archives - the National Personnel Records Center - but all of NARA's facilities are closed to visitors and their duplicating facilities are shut down for the foreseeable future thanks to COVID. Once they reopen, they say they'll start working off the requests that have been piling up since they shut down, in the order in which they were received, so it's going to be months before they can get around to any new requests like ours. And we're working to a deadline with our publisher; we have to have the illustrations submitted very soon, it's the thing that apparently takes the longest lead time in getting a book put together. I'll check the local universities though, I hadn't thought about that. Thanks!

 

[OldGeezer]

Contact Ester at [email protected].
She is doing this sort of work all the time. I have dealt with her on other matters and found her to be extremely helpful.
Her video at Ken Jungeberg Collection | AirCorps Library may give you some clues.

I hadn't even known about the Air Corps Library - thanks for the pointer!!

 

[special ed]

As a retired Kodak employee, I serviced planetary Microfilmers at several companies. These 35mm units were quite an investment so the universities may still have them. The filming was usually done either by volunteers or grad students so a project took a long time. Other companies were Shell engineering, Boeing and anyone who might have engineering drawings. If you have a safe place to spread the drawings, the creases will begin to relax. A dark place will retard fading.

 

[OldGeezer]

I think we have a workaround for this after all. I pried the lid off of our old scanner, to remove the obstacle to the extra paper when we were trying to scan the middle parts of the large blueprints, and it scans just fine without it. So without that obstacle, we should be able to scan big prints section by section without introducing any of the distortions that we got from the camera lens when we were doing this last year. I won't be able to get the blueprints again until May but this will be the first thing we try. (Somebody asked the scanner manufacturer several years ago whether they could do this very thing, and the mfr said it wasn't possible because there's an essential wire bundle in the lid. Turns out that's only for the automatic document feeder, and while it gives an error if you try to disconnect it, it works just fine if you lay the lid next to the body of the scanner with the wire bundle still attached to both.)

 

[MiTasol]

good luck with that - it certainly looks doable. May I suggest you create a "table" from a sheet of MDF or similar with the scanner in or near the centre so that a much larger percentage of the blueprint is flat while scanning. I often put an A3 size weight on folded objects when I scan them using my scanner. It has a thin layer of middling soft rubber so it cannot damage the pages or scanner and weighs about 7 or 8 kg (about the same as a very heavy book)

 

[Doom!]

I work in a reprographics shop (fancy name for blueprinter). We deal with delicate and irreplaceable documents all of the time. If they are fragile we sandwich them between two sheets of clear acetate and then feed them through the scanner. Any reputable reprographics shop will do this for you. We have seen some pretty ratty documents and not had any mishaps.

 

[MiTasol]

Damn that is so obvious once it is pointed out. I will try this in a few minutes using heat set laminating film on some A3 pages to see if that is a viable option for the acetate sheets. The scanner should not cause the material to set but just in case I will just scan something worthless like today's junk mail

Just in case laminating pouches do not work - how do you keep the sheets together to prevent only one going through the scanner?

 

[Doom!]

The acetate is larger than the print with the leading edge taped together. Any extra in the image can be cropped from the digital scan.

 

[MiTasol]

Thanks Doom.

I tried the same page with and without a laminating sheet and the difference is negligible in clarity. Given the laminating pouch should hold the page better than the scanner glass and lid I think this will not only be a lot faster but result in a much better scan. I will know soon with one of the next Anson manuals I post. Hopefully it will roll out some of the wrinkles on some of the pages.

I rated your first post above bacon - the highest praise on this forum

 

[special ed]

Many ideas can be seen from searching "Microfilm equipment". Most of the large and/or state universities have (or used to) have large microfilmers. Also called/defined as planetary microfilmers. Students usually did the actual filming, a boring job, and it may be possible to volunteer to film the large documents as a learning tool and in return your blueprints could be filmed as payment. The older, long established print shops may have answers to your questions in person.