IDE Database - Archival procedures notes

General

By Date

5-10-1994 Scanning procedures

Scanner used is HP ScanJet IIc hooked up to a 486-based PC with MS Windows 3.1, an ET4000 graphics card running at a resolution of 800 by 600 with 256 Colors. Installed memory is 4MB. SEM polaroids were scanned using the "Scanjet" software that shipped with the scanner. Parameters used were:

Type: Black and White Photo
Path: Screen (i.e., 75 dpi)
Scaling: 145%
Contrast, Brightness: Changed for every image individually
Image Size: Near but less than 500 pixels horizontally

To get calibration information on the size reduction, this is a scan showing part of the front cover of NASA CP-3134 (Proc. 1st LDEF Post-Retrieval Conference). Scaling is 100%. This directory contains several other scans I did not include in this sheet.

5-11-1994 Scanning SEM images

Most of the polaroids were slanted presumably due to the mechanic setup common on SEM's. See figure below for an example.

I tried to compensate this as good as possible (with varying degrees of success).

5-11-1994 SEM Stereo images

Some images for MOS 1192 were taken at 0 and 6 degrees stage tilt angle for stereoscopic viewing. I tried to scan the two images at the same magnification hoping to get the same parts of the features. The two images usually had different image quality affecting contrast and brightbess of the image which I tried to compensate. The resulting GIF images were then combined using the ImageMagick software package and a DEC 3100 at the Lehrstuhl für Raumfahrttechnik, TU München.

6-28-1994 color scans

It is impossible to exactly reproduce colors without color calibrated hard- or software. The images of trays C3, C9, B12, and D6 are therefore not accurately reproducing the colors of the LDEF inflight photographs. To give you an idea on the possible errors caused by scanner color response and resolutions, reduction to 256 colors, screen resolution and software effects, a scan of a color image from page 1204 of the LDEF-1 conference proceedings might give you an idea on color reproduction problems, although this example appears to be more extreme than the LDEF color deviations.