APPEARANCES OF A PLATE, ETC. 
127 
background. The light parts of the negative—dense or 
non-actinic parts of the object—are clear, without 
muddy or foggy appearance, yet full of detail, if detail 
existed in the object. The gradation from light to dark 
is even, and a long scale of densities is represented on 
the negative, unless the object consisted of simply 
opaque and transparent tissues, as in the case of 
diatoms. It is practically impossible for a beginner 
properly to estimate the quality of a negative. It is 
advisable for him to show his negatives to someone of 
experience who may point out their shortcomings. 
If the gradations of the negative are full, and all the 
details of the object represented on the plate, but the 
whole density too great, such a state, in fact, as may 
arise from slight over-exposure or over-development, it 
is easy to rectify matters by “ reduction.” If all the 
details are represented, but there is a want of contrast 
in density between one part and another—-if the ground 
is grey instead of black, as may happen after over¬ 
exposure or under-development—“intensification” may 
supply a remedy. But if the plate is dense at one part, 
and thin and wanting in detail in another, due to under¬ 
exposure, it is practically impossible to amend it, and 
the only plan is to make another exposure. 
In any of these cases it is, as a rule, preferable to 
make another exposure: but under certain conditions 
already alluded to on page 122 the only course may be 
to intensify with or without previous slight reduction. 
Thus, when we are dealing with very pellucid, or 
weakly-stained objects, or such as are difficult to repro- 
