T i T T T T TT mT T . T T ’ + T | - 6 STEP wECGE EXPCSLAES 3 aT EFS NANG CF Flim, 3 AT END. ! - r j 20— ~ : t —q ° _ : 2 . ‘ 2 op ey iy ste dt ~2.0 °o +o we TOYO a1.9— 1 2 « - a . . 8 > w i: r 4 — an = J ' - -10 LOGiqg RELATIVE EXPOSURE 0 Fig. 11.5--Control step wedges, fila T-11. axis is called the inertia point. It is found that the inertia point position is quite insensitive to variation in development processing. The inertis point from the calibration filw was therefore used to place an absolute energy scale on the O-log E curves obtained as follows. The exposure ratio berween any two channels of a streak camera is known from the relative filter transmissions. Tous at any fixed time, four points on a density-versus-relative- exposure curve are obtained. By going to other times, other groups of points can be obtained, and thus a complete curve san be built up. It-was found chat data from chaonels with ainimm exposure (and to a such saaller extent the one with che next greater exposure) did not fit well with che higher density channels. Subsequent laboratory tests have shown that there is suificienc scatter- ing in the fils and cazera to cause a distortion of rhe channels which have been attenuated factors of 100 to 1000 as were the mo least Zense channels. Therefore, only data froa the two aost danse chacnels on each fila sere coa- sidered reliadle and used ia subsequent asalysis. oo The autocalidrated curves