An enlarger consists of:
a. The baseboard
b. The column
c. The enlarger head
The enlarger head can be raised and lowered to increase or decrease
the size of the image on the baseboard. It also houses the light
source and a removable negative carrier. An enlarging lens is connected
to the head by means of adjustable bellows. The lens openings are
marked similarly to the f-stops on a camera lens.
We distinguish between condenser and diffusion enlargers.
a. Condenser Enlargers
A large converging lens (the condenser) is used to direct the light
from a bulb through the negative to the point of focus of the enlarging
lens. Some condenser systems need adjusting for enlarging lenses
of varying focal lengths. The image of the negative projected on
the baseboard will be more contrasty than that projected by a diffusion
enlarger and dust and scratches show up more clearly.
b. Diffusion Enlargers
In diffusion enlargers a translucent grainless diffuser is placed
between the lamp and the negative. This will give diffuse, even
illumination to the negative. Unfortunately, since much light is
scattered, a powerful bulb is necessary and this may produce heat,
making ventilation for the lamp housing necessary.