General Guidelines

3000 ÷ greatest length (in inches) = number of ppi, and digitize at 100%.

Note: that it is the original document which measures 8 x 10, not the final digital file.

Examples:

• To digitize a document measuring 7 x 8.5 inches:
  3000 ÷ 8.5 = 352 (round off to 360 ppi).
• To digitize a 2 x 3 negative: 3000 ÷ 3 = 1000 ppi.

1. TIFF - the master file, and the archived final version of the image.
2. JPEG - the surrogate file, used for circulation and consultation, and the current image format attached to the catalogue record.

1. For text and photographic documents, the image is saved at n x 768 pixels.
2. For documents with small characters, the image is saved at n x 1130 pixels.
   JPEG files are saved at 72 ppi, with the lower level of compression (level 12).

Note: The empty space, represented by the underlined blank (e.g., n x 768 pixels) is left open to accommodate variations in size. The number of pixels - 768 or 1130 - refers to the longest measurement of the document being digitized.

1. a) Use a good quality CD: CD-R, rather than CD-RW, with a reflective gold coating (e.g., MAM-A CD-R Gold).
2. Burn the CD at a slower speed (4X) to ensure a "deep" impression.
3. Check that the information burned into the CD has been effectively transferred.
4. Use water-based ink markers.

Furthermore, to secure RGB variance on Kodak Q-14 colour and grey scales:

1. The reading of white from the Kodak scales must be made within a range of 5 pixels.

   

   

   Table of Reference Levels

   	White	Neutral grey (M)	Black
   Reference Levels	237-237-237	102-102-102	23-23-23
   Recommended Levels	233 to 248	98 to 106	19 to 27
   Levels Used for CMCC Collections	233 to 248	145 to 155	30 to 40

2. The data for each of the RGB channels must not vary by more than 3%.

   

   Scales are useful for correcting a poor-quality digital image, or for batch digitization.

   Note: When correction is necessary, do not save your changes on the original image. Instead, create a duplicate digital file and work on that version.

1. The Kodak Q-14, mainly used alongside the material being digitized or photographed.

   

2. The Kodak Q-60, used primarily for reference purposes.

   

3. A homemade scale, based on the squares of the Kodak Q-14 scale, is also used for smaller objects in the CMCC collection. It is important that the squares be identical in size to one another (squares of 1 cm ² are recommended), and it is useful to include a reference measurement.

   

   

4. A small commercial white-grey-black scale, used for macro photography of artifacts.

   

   Notes:

   1. For reliability purpose, the scales used must be clean - without dust or stains.
   2. The use of a detailed colour scale, such as MacBeth digital colour checkers, may come in handy when working with specific types of media.

   

   

The histogram shows the distribution of colour levels between the two extremes - pure black (level 0) and pure white (level 255).

It is sometimes necessary, before saving the final digital image, to work with cursors within Photoshop® to optimize quality at both the black and white levels.

Note: It is best to make any corrections to the image on a duplicate digital file.

1. When the quality of the original material being digitized is of less importance;
2. For consultative and visual reference purposes; and
3. To correct a group of images with similar issues or problems.

Note: Should this method be used, it is important to remember that this process cannot provide an optimal digital rendering of each individual image.

If you opt for batch digitization, follow the steps below.

1. Digitize a colour scale before each digitization session.
2. Balance the RGB channels on the first image, as indicated in the general guidelines above.
3. Save this data and apply the same ALV to all subsequent images.

1. Hardware (scanner, camera, monitor, etc) must be calibrated on a regular basis.
2. Room wall colours should be neutral.
3. Room lighting should be kept at the lowest level.
4. Monitor should be protected from direct light to avoid reflections.
5. Working area kept as dust-free as possible.

1. Using a regular lens (unless otherwise specified).
2. Using a professional studio flash set-up, not the camera flash.