Printing 
The losses between the negative and the print are so 
large by current practice, that the case for direct use of 
the negatives is very much greater than is generally 
supposed. When making prints, the subject is of course 
the negative, and maximum and minimum negative densities 
should govern the choice of printing materials, and set the 
contrast and exposure in the same way that the subject 
brightness range should set the procedures for making the 
negative. By current practice nothing so sophisticated 
as this has ever been attempted, but it may be observed 
that this approach would be not at all difficult in 
circumstances where negative densities were spread exactly 
between two fixed levels as ha3 been advocated in the 
paragraphs dealing with the negative. 
The following paragraphs will deal with current 
practice. It is proposed first to consider failure to 
reproduce the negative density range, and the complete 
loss which occurs outside the range reproduced. Secondly 
it is proposed to consider the severe resolution degrada 
tion inside the range reproduced. 
Loss of Negative Range 
When prints are made without ary form of dodging, 
very considerable loss of detail frequently arises due to 
the inability of the printing material to accommodate the 
negative range. Table I considers in column 1 three 
negative detail density ranges such as may be met by 
current practice, and indeed are often much exceeded. 
For the printing of these, three grades of printing 
material are generally available. If these are used 
according to the maker’s recommendations they have the 
following approximate gammas. Soft grades 1*6, Medium 
grades 2.0, Contrasty grades 3*0. In consequence 
the negative density range to be printed must be multiplied 
by the gamma of the material used as shown in column 2. 
The range of a paper print may be taken as about 0.9 
between complete cut offs. That is to say without any 
reference to the severe resolution losses and in particular 
those approaching the range extremes. Thus when paper is 
used, a range of 0*9 is available to accommodate the 
various ranges shown in column 2. If there is no dodging 
during printing, column 3 shows the percentage of negative 
range completely lost between the cut off levels. 
In the case of diapositives, if there is no restric 
tion at all on the amount of light used for viewing, the 
range between cut off levels is probably more than twice 
the range of a paper print, but the diapositives have to 
be used in plotting machines where the viewing light is 
restricted, and the requirement is generally for a print 
’’having the appearance of a lightly pencilled sketch”. 
For most plotting machines the range between cut off levels