Scanning Decisions
Okay, so at the start of a large scanning project there are few decisions to make. Here I record some of them (just some!) and my reasoning. I am writing this in-between scans (grin), a sentence at a time.Technical Decisions
Mary and I compared various Dots Per Inch, DPI (or more accurately, Pixels Per Inch, PPI) and did some research on the web. On the web, the general consensus was that 600 DPI was "perfectly good", but when looking at our first sample image, Mary and I both felt that 1200 DPI provided (very slightly) better resolution at very high zooms.In terms of color depth, the choices are 24-bit (8 bit for each channel, Red, Blue, Green) or 48-bit (16 bits for each channel, RGB). It is impossible to determine the difference between a 24-bit color image and a 48-bit color image on a computer monitor, because all computer monitors only show 24-bit color (apparently).
Also what file format? JPEG (web/internet standard) is a "lossy" compression format which means smaller file sizes but less careful preservation. JPEG can only represent (max) 24-bit color. Meanwhile TIFF images are perfect, lossless storage and can hold 48-bit color, but they take up a lot more space.
Finally, how long does it take to scan an image? And how much disk space does it take?
Based on some experiments, we decided on the following parameters:
- 600 DPI @ 24 bit color for "less important" images
- DISK SPACE: 2-3mb
- TIME TO SCAN: 25 seconds
- USED FOR:
- Scenery without people in it
- Hotel bedrooms (without interesting luggage or personal effects)
- Tourist attractions
- The backs of photos (when there is writing on the back)
- 1200 DPI for "more important" images (see below)
- DISK SPACE: 820mb (!!)
- TIME TO SCAN: Over 2 minutes
- USED FOR:
- Any scan with someone we know
- Pictures which are especially beautiful or notable for any reason (gorgeous scenic views, anything which looks historically interesting, etc.)
What to scan
This is a more interesting question than one might assume. Currently, our decisions are:- Take a camera picture (with iPhone) of the book / album itself
- Only the front is required, unless there is something interesting about the back (e.g. hand writing)
- Scan the fronts of all photographs
- Scan the backs of photographs if they have writing on them
- Scan any labels
- Position the label on the scanner so that it is either above or to the left of the picture
The Scanning Process
So far, in terms of a scanning process, I have the following:- Open up the box
- Create a folder for the box & label it
- Get the first item
- This is a folder, album, book, batch of letters, etc.
- Create a folder (under the box folder) for the item & label it
- Take a picture of the item with a camera (for context)
- Only take a picture of the front & spine, unless the back is super interesting for some reason.
- Extract the pictures from the book
- Preserve the order!
- Scan the fronts of each set of pictures
- Pack as many onto the platen as possible
- In order, from left to right, top to bottom
- Scan the labels as well
- Place them above or to the left of the photos
- Take care that there is enough blank-space around all items on the platen
- Scan the backs of the photos
- Turn them over and scan them in-place
- Only scan the backs if they contain writing
- Remove the pictures from the scanner and place them into a stack
- Do *not* put the pictures back into the photo album
- Preserve the order
- Put the labels into the stack before the photo which they describe
