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:
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.
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
- 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.
And then you get much more clear plan.
The plan in question and further info of this nice -30’s biplane can be found here.