Production of a Grader Training Aid & Training Method

 Production

Method

Foreword

This section is dedicated to a practical method to train a Grader. Its use is limited within a laboratory and under the control and the guidance of an experienced Grader. It can also be used - under the same conditions - within Archives in order to train staff members who are appointed to check the quality of prints coming from laboratory. As we said, it is NOT meant to be used as an On-Line training, nor as a self-learning instrument, because it needs strictly the presence of a supervisor.

Production of the Aid

  1. A length of Eastman Colour Negative is loaded into a conventional 35mm still cassette and exposed in a 35mm still camera, frame by frame using conventional filters and speed indices as recommended for the product.
  2. The length is processed normally and spliced into a loop sufficient for a Bell & Howell Additive Printer.
  3. The negatives are printed by conventional trial and error methods (or using a Video analyser) until most frames are near correct. The variation from one frame to another is not much more than 4-6 printer lights in both colour and density if the negative has been exposed with rigorous interpretation of exposure requirements.
  4. A programme tape is then punched in which the final R, G and B light values are adjusted as in the table provided.

Example:

Printer setting (a) is set at the value found in number 3 above. This might be 25, 28 or 30.

Printer setting (b) is set 4 at this value corrected by -2G. Thus, this value will be 25, 26 or 30, and so on through 92 printer settings.

These prints are then produced.

  1. 5) 91 frames from one negative are mounted in 2 x 2" card or glass mounts and placed in sequence in a 35mm still projector magazine, which has numbers for each slide position, for example a Carousel. The numbers on the magazine should correspond to the numbers of the prints in the table. (No. 92 is a second 'normal' as a check of printer and process stability and should be identical with No. 1).
  2. 6) Many projectors will not take all 91 prints and so some may have to be omitted. It is best to omit some of the extremely off balance prints

Production of the 91 print ring-around

Production of 2 37 print ring-arounds

 

 

Training Method

1) The instructor projects a single print on a still projector, which can be any of the 91 prints available, but is usually one of the furthest out.

2) The student assesses the correction and informs the instructor.

3) The instructor uses the tri-linear display to find the print with the student's correction and projects this.

4) The student accepts this print as correct, or makes a further correction as necessary.

5) Once the student is familiar with the system, he may take the place of the instructor as the projector operator.

 

Example

a) Print No. 89 is projected on the screen.

b) The student assesses the print as too R and decides on a correction of +8 printer lights red to correct this.

c) The instructor finds the corrected print by moving from No. 89 four places in the +R or Cyan balance direction (each jump represents two printer light changes). Thus, he projects No. 12.

d) The student is still not happy with this and decides that now it is too Y. He decides on a -4B correction.

e) The instructor now projects No. 54 (two spaces in the -B direction from No. 12).

f) The student decides this is acceptable.

 

Notes

  1. The initial choice of a good average balance at stage 3 of the production should be done by projection with the projector to be finally used.
  2. No. 1 or 92 does not have to be a perfect print since personal choice will cause the finally accepted print to vary. No. 1 should be, however, within two printer lights of most graders' preference.
  3. If two projectors are used with two subjects, a scene to scene balance can be achieved by printing the first one, leaving this projected and matching the second to it; projecting the two images side by side.
  4. As experience is acquired, a starting position can be used nearer to the centre.
  5. It has been found that this method maintains a high sense of involvement and can shorten the time required to gain experience in grading. Obviously, the larger the number of subjects available, the better, but each subject should be done at least twice starting from different balances.