UNES PER METRE 
13.33 
80 
10.00 
60 
6.67 
40 
3.92 
24 
2.47 
15 
1.64 
10 
1.09 
6.7 
0.82 
5 
of the grain of the printing materials currently in use. 
Berg has shown that the only means of recovering the full 
negative resolution on these materials is to enlarge the 
negative eight times through a really good quality 
enlarger lens. The writer has confirmed this, and 
confirmed also that full recovery of the negative resolu 
tion on these materials is not possible at enlargements 
less than eight times.(5) 
4» Examination of the prints 
Referring again to figure 2 it will be seen that a 
magnification of x 30 was necessaiy before the eye could 
see the last group of lines resolved on the negative and 
optimum magnifications for diapositives and paper prints 
were respectively x 25 and x 16. These are very much 
larger magnifications than are generally used by current 
practice. 
4*1 • On the basis of figure 3> Table II lists in the first 
two columns the target resolution to be expected by the 
use of viewing devices currently used on the assumption 
that their performance at magnification is equal to that 
of the good quality microscope used in the writer’s tests. 
If this should not be the case, the resolutions would of 
course be lower. Column 3 lists the percentage loss of 
resolution due to the limitations of the resolution of the 
printing material referred to previously, and column 4 
lists the addition percentage losses due to the use of 
insufficient viewing magnification. The total percentage 
loss assessed by the tests in figure 2 are listed in the 
last column, and vary between 44 and 89^ - the usual loss 
being well over 50^. It must be remembered that these 
resolution losses apply only in the circumstances of the 
tests, and can of course apply only in that part of the 
negative density range which has not already been totally 
lost between print cut off levels.