Cleaning up background images.

[Chilidawg]

I quite often have to work with scanned in images of very old drawings. (some going back decades)

These are usually sent to me in PDF format. I extract a TIFF image from the PDF, then will open it up in Microsoft image manager to tweak the rotation, save, then reopen it up in Microsoft Paint to clean up the image. (delete trash marks, old notes, redraw / darken lines, etc.)

Sometimes i find I spend just as much time working on a drawing in Paint as I do in AutoCAD.

 

Does anyone else have a similar workflow?

[SLW210]

It is usually easier to redraw from scratch or insert in AutoCAD and trace over, though I have had some luck with Illustrator and some other convertors, really depends on how good the scans are.

 

Ther are places that will do this for you for a fee, results vary.

 

Autodesk has Raster Design available, I'm thinking of giving it a test run here soon, as I have a few old drawings to scan into AutoCAD.

[Chilidawg]

I find it easier and faster to simply clean up the old Tiff file.

 

I have traced over some drawings in the past, but I find that in some cases that the resulting drawing implies a false sense of precision when I am guessing at the actual dimensions. Also, I don't want to spend too much time drawing in trivial details, but I want want them to be visible in the final drawing. Since most of my drawings are related to environmental investigation or remediation projects, I try to avoid being too precise with actual locations as things are never quite where you think they are.

[Chilidawg]

I should add that many of the originals were 8.5 x 11 sized when they were scanned in.

[Dana W]

I should add that many of the originals were 8.5 x 11 sized when they were scanned in.

Oh, now there's most of the problem. Scaling those up in AutoCAD will also scale up the pixels in the pdf/tiff.

[cadvision]

If you are going to work on the scanned file ask them to supply a TIFF file to start with, scanned at 400DPI or higher. You might then want to look at professional raster editing software like WiseImage from CSOFT (www.csoft.com). These guys have been writing raster programs for 20+ years.