2. The "cut and patch" control of conditions devised for color media sampling, and the time-elapse pictures of a medium's color stability seem to be reliable techniques. They should be evaluated again with a control. 3. Comparing unexposed and exposed samples of the color media of the same manufacturer and the same color over time between trials or within trials using a time-elapse technique can serve as a validity check. 4. The empirical standard of 10% as a significant and detectable spectral luminance difference for different hues of color media in theatre work should be evaluated by expert and audience, using accepted psycho-physical techniques and using both the judged and the adjusted differences as cross-checks. This standard will go far to indicate when color media should be changed. 6.4 Cinabex No. 33 Deep amber 5. Counting the number of decision points or critical tests which the spectral response of color media should pass successfully in a group of comparisons, and evaluating the number passed or failed provides a rough but relatively reliable evaluation of the quality of spectrophotometric curves. For example, a lavender curve must have relatively high absorption in the green-yellow area to be acceptable. The development of some numerical standard, like percent of transmission, would be a help in quantifying these comparisons. 6. A system to evaluate spectrophotometric profiles expeditiously should be developed using spectral luminous efficiency standards.7 7. The problem of selection of color media for theatre production in the light of early deterioration of color and consequent similarity to other hues in the wide variety available should be examined. 6.5 Cinemoid No.2 Light amber 6.6 Brigham gelatine No.1 7 Special lavender f-+---+--I++-rl--r--I I I I I II 1/1/ VI I II I 6.10 Cinemoid No. 36 Pale lavender 6.11 Brigham gelatine No.3 7 Dar!< blue f-+---+---II--,--1 -- A 6.12 Rasco gelatine No.2 64 Urban blue r--+-r-----------t--.-r- - I - - D h' 'I II;'~ II 1\ \ f'. I, \ I YI \ I", II /I .'-' 18 ;~;::: .' 1\ / THEATRE DESIGN & TECHNOLOGY MAY 1967