Colour Negatives

Notes

• Placement of a negative's emulsion side varies from one scanner to another. To ensure that the emulsion is against the proper face of the optical reader, follow individual scanner guidelines.
• Do test scans if possible. Depending on the quality of the negative, it is sometimes preferable to digitize as a positive, and then invert the image with image-processing software (e.g., Photoshop).
• Concentric ring patterns (dark and bright bands) may appear while scanning negatives. These patterns are called "Newton's Rings", and are caused by the interaction of light waves reflecting on two glossy surfaces - one convex and one flat - and the air pockets between them.
• Possible ways to avoid them:
  1. Use a mount to raise the negative, thus avoiding contact with the scanner glass.
  2. Insert an anti-Newton's ring sheet between the negative and the scanner glass.

Remarks

• The technician must verify the final image by comparing the original negative with the digitized version.

Procedures

• Verify the film type. If the scanner offers this option, select the appropriate film profile and apply it to the digitization session.
• Ideally, the colour scale used should be identical to the film type (e.g., Fuji film digitized using a Fuji scale).
• If the type of film is unknown, do test scans to optimize digital rendering of the image.

Recommendations

1. 300 ppi, with a minimum of 3,000 pixels for the longest measurement (8 x 10, or 1:1 for formats larger than 8 x 10).
2. Refer to the general guidelines to calculate the number of ppi required for a given dimension.
   Note that it is the original document which measures 8 x 10, not the final digital file.
3. Digitize in transparency mode.
4. For reference purposes, digitize a transparent colour scale (on film) before each digitization session.
5. Digitize as a positive, and then invert the image with image-processing software (e.g., Photoshop®).
   

   

   

6. If the negative allows, reframe the image to preserve the border and any notations found there.
7. Balance the white levels in the whitest zone (D-Max), then balance the black in the blackest zone (D-Min).
8. Convert in Adobe RGB 1998 profile, 8 bits per channel (total 24 bits).
9. Save the image as an uncompressed TIFF, named to standards established by the Corporation's Photo Archives.
10. Produce a JPEG version as described in the general guidelines.