Getting better scanning results from vintage plans

Now with better time I have been tuning my processes for better scans. For mini-review of scanner see here. This is continuation article of that mini-review, but these comments apply also to any scanner.

1. First, if plan is really vintage, try ‘Document type : Grayscale CAD/map’ instead of normal colour. For example, see below:

with colour

with Grayscale CAD/map

This is rather counter-intuitive, but idea is to let scanner do automatic removal of yellowish tint. It performs rather nicely.

2.  Do not use high resolution.

Changing resolution from normal (300) to fine (600) dpi creates rather large files and makes things much more complicated. Using 600dpi resolution creates A1-scans of PDF-size 16mb. And if you open that file and make some changes you end up with 200+ mb workspace and 150mb files. Which are just too much.  Using 300dpi has enough resolution for normal model aeroplane plans.

3. Use backing paper if plan is really fragile.

Use normal A0/A1-roll paper as backing if plan is almost schreds. Just tape leading edge of plan to paper with small pieces of tape (3M Magic Scotch). Note that use as small amount of tape as possible and only on leading edge. By leading edge I mean the edge which goes into scanner.

really brittle plan with all kinds dents.

taped to paper, nicely and safely waiting for scan

4. If plan is vintage drafting paper then do following

  • scanner can do wonders with yellow tint removal, but it cannot help translucent drafting paper hue. You can try to use backing paper to make effect smaller, but it does not work well enough

Plain Grayscale CAD

Graysale CAD with paper backing.

  • Get adobe photoshop, elements is just fine and use Levels-tool. Move white end from right side to the left part of black curve. See below.

Using levels

And then you get much more clear plan.

Good enough.

The plan in question and further info of this nice -30’s biplane can be found here.

Large format scanning & mini-review of Contex SD One MF 36″

I have always been struggling with finding original aeroplane plans. Normally you do not find them despite that almost everyone at field and in events says ‘yeah you just go there, plans are there’. Typically I get comments like ‘yeah I saw the plans there in seventies, they must be still there’. Once I found out that the building where they were supposed to be had been demoslished decade ago.

Anyway, the key question is getting the plan. Then second question is to get plan in electronic form. ie. to scan it. You can get that service from printshops but there are couple issues. a) it is expensive, typical cost for scanning full size plane plans is around 200-300€. b) those printshops do not concentrate when they scan plans. They do not worry things like scale, is paper straight, …. Producing scans which are not optimal.

To solve this issue I have been dreaming of getting own full size scanner. They are really expensive and large, requiring storage space. But all this has now changed. Contex introduced slightly smaller unit couple years ago and the price is not totally out of reach. Product was named Contex SD One, then upgraded to SD One+ and finally SD One MF. Scanner comes in three sizes 24″, 36″ and 44″ with 36″ corresponding A0-roll size. Colortrac introduced similar model. Contex SD One MF model has also large screen allowing non-tethered use and scanning to network and usb stick. This is actually quite important as it reduces amount of stuff needed to make scans.

Couple months ago I decided to purchase Contex SD One 36″ MF. Main reason is to be able to make scans of original plans to allow more precise models. Also I want to get full control of workflow eliminating printshops and the errors they seem to cause. Scanning is obviously more economical per page, but the cost of scanner itself is still huge for hobby company.  Being portable allows me to drag scanner to museums and make scans there. Also it allows me to store scanner away when not used.

Scanner arrived couple days ago. Packaging is rather large as axpected, unit weighs approx 12kg so it is not lightweight. When setting scanner up I noticed that the scanner activation key was incorrect. It was key for some other scanner as the serial number and model was incorrect. Also, I simply do not understand why this activation was necessary. Quick call to local Contex representative and couple days wait solved this issue with new activation key. One should note that you can use scanner which has not been activated, there is 50h usage limit and I do not know what happens if that is exceeded. While setting scanner up I noticed that it kept hanging up occasionally. I guess that this was caused by factory installed firmware version, 4.0.1-002. I updated firmware to 4.0.1-010 which can be found at Contex website. Updating was straightforward and painless procedure.

User interface of scanner is rather nice. There are no keys in scanner and everything is done via rather large touchscreen which is extremely responsive. I could enjoy better contrast, but all in all screen is great. Also there are limited editing possibilities (preview, adjust, crop and annotate, contrast, color, …) via screen, which I have not tried. Update 2018-02-20 : I have tried editing functions and they actually work rather well. But they are slow.

Then to scanning. First I noticed that this scanner produces really nice looking files. I tried several settings and quickly landed to rather nice set of settings for typical plans.  I wanted to get rid of yellow tint and get reasonable resolution. Scanning is quite fast with these settings, I have not clocked it but  I have no reason to suspect advertised speed of 4.8cm/s. My selected settings are :

  • Quality : normal (300) or fine (600) dpi
  • Document type : Grayscale CAD/map
  • Validation : no
  • Size : auto
  • Format : PDF. Using TIFF creates rather large files but it might be usable in special cases. For jpg files you can specify compression, default is 80.

I have made several scans but still I am experimenting. To see example of typical resulst check this link. It is an F1A0-glider Salko. Designer is unknown, but if somebody knows him pls let me know it as I want to credit him for great looking plan.

You can output scanned files to several locations, but there is an major gripe regarding cloud destinations.

  • USB – scan is output to memory stick, works great. Update 2018-02-20 : However – I have experimented using small portable hard drives with USB-connection. This does not seem to work reliably, even if the drive functions properly with PC. I suspect that the current requirements of drive’s are more than scanner circuit can produce. With couple drives some work, some not. And those which work do not work reliably. USB interface in scanner supports USB 3.0 specification and complains if you try to use USB2 memory. Documentation does not state maximum size of memory stick.
  • Email – scan to defined address or addresses, works great
  • PC – scan file to PC, you need to install Contex.LINK application to pc. Pls. note that scanner is connected to PC via LAN/Wifi. Ie. USB connection is not used. Actually this is great as it allows much more freedom in cabling etc. Then again, in sites where you have no connection to network it is not so great as then there is no connection. Using memory stick removes that problem.
  • Dropbox, Box, Google Drive, OneDrive. These destinations require installing Contex.LINK to PC.  This has been implemented in such way that scanner outputs scan to PC which then relays scan to cloud destinations. This is not nice as the whole idea of scanning directly to cloud is … compromised. I tried Dropbox and it seems to work nice, but I still wonder that is the PC really necessary. IMHO this is kludge. All in all, it works.
  • Rainforest365 – this is some kind of cloud teamwork sharing site/app in IOS & Android which is currently in beta so cannot say more about it.

Manual also mentions that you could use USB connection to link PC and scanner using third party application. I think that this is unnecessary, as I am not aware of any applications utilizing it. For example the well known scanning solution Vuescan by Hamrick does not list any Contex scanners on their supported scanners page.

One thing notably missing is the ability to scan directly to network drive (ie. NAS or similar). I suspect that one could try to define scanning directory in PC which is really an NAS directory visible from PC. Again this is not nice approach as the PC is unnecessary element.

One thing worth mentioning is that scanner can also do copying. This is done by first scanning material and then automaticly outputting file via defined large format printer. This seems to be nicely implemented but I have not  (yet) tried it.

Regarding network in general, scanner can be connected to normal LAN using cabling or Wifi with supplied Wifi-USB-dongle. This works nicely.

To summarize:

  1. Scanner produces great looking scans and it is quite fast.
  2. Connectivity is great, but cloud scanning seems to be somewhat kludge.
  3. Scanner is large, but given the paper size is quite compact

All in all : rather nice scanner producing good results.

For next episode of this mini-review see ‘getting better results with vintage plans.’.

(pls. note that I am in no way affiliated with Contex or their local distributor