Hamilton College Digital Collections


Table: Specifications for Digitizing Slides and Negatives (transparencies, glass plates)
Use Resolution Bit
Depth
Color
Space
Dimen-
sions
Editing/
Processing
File Format/ Compression Storage

Archival
Master
(AM)

Long-term archive

35mm=2700+ ppi1

120mm=? ppi
6x7 cm.=1000 ppi
4x5 in.=800 ppi

8x10 in.=400 ppi

24-bit

RGB

At least 4,000 pixels on LS. 2

Check grayscale and color accuracy

TIFF, with little endian (IBM PC) Byte Order; no compression; save with embedded ICC Color Profile

Stored on 2 media: CD, DVD, tape, spinning disk

Working
Master
(WM)

To create derivatives.

Publication printing.

300 dpi

sRGB

-Change file format.3

-Converted to sRGB

-Tone & color adjusted

-Sharpened

Same as AM, but may be compressed with LZW compression if saving storage space is essential 4

If kept, same as AM.

Static
Delivery File

Internet delivery

150 dpi

600 pix. on LS (no zoom);
600+ pix. on LS (zoom)

-Reduced dimensions
-(Converted to grayscale if b&w)

-Sharpened

JPEG, medium quality, 5-7; or high quality, 8-10 (of 10)

Spinning disk and backup tape

Do not scan the slide mount - just the film.

[1] - Scanning a 35 mm. slide or negative at 2700 ppi is equivalent to scanning at 300 ppi and increasing the size of the image by 900%. This yields an image with about 6000 pixels on the LS. For smaller slides, increase the scanning resolution if necessary to achieve at least 4,000 pixels on the long side - 6,000 would be even better.

[2] - Negatives and slides that are larger than 35 mm. should be scanned in the same way as 35 mm. negatives and slides, but have a dimension of 6,000 pixels on the long side.

[3] - If you are using Photoshop to edit the Working Master, change the file's TIFF format to PSD, Photoshop's native file format, which allows for more editing functionality.

[4] - To provide zoom and pan functionality for an image, you can upload the Working Master (TIFF) file to a "full resolution" CONTENTdm collection. CONTENTdm will then convert the TIFF format to a JPEG2000 format. [See Submitting Full-resolution Images.]

(Updated: May 6, 2008; December 17, 2010, pjm)