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Showing posts with label light box. Show all posts
Showing posts with label light box. Show all posts

Tuesday 27 December 2011

Contact printing.


Now that you have your negatives safely stored and indexed, you need to sort out which negatives you are going to print. Trying to judge this by holding them up to the light or by laying them on a light box can be difficult. The best way is to produce a contact print showing all the frames on one sheet of photographic paper.

There are special frames that allow you to do this. You can buy contact print frames which consist of a glass top with film holders attached and a solid base with foam on that clips shut. For 35mm or 6x6 (medium format) which hold seven rows of six for 35mm or four row of three for medium format negatives. The frame holds the negatives so you can see the frame numbers on the print, you place them with the shine side up and put a soft grade light-sensitive paper on the base. Then shut the frame to bring the negatives in contact with the photographic paper, hence contact print.
Another method of contact printing is if you use clear plastic negative holders, you can place these directly onto the photographic paper. The problem with this method is it does not hold the negative completely flat to the paper which means that some of the pictures may be distorted. A way round it is a clean sheet of glass that is big enough to place over the negatives.

Wednesday 23 November 2011

Enlarger


An enlarger consists of:

Enlarger for 35mmm negs
only. with out multigrade
head. Condenser type.

A baseboard on which enlargements are made; a column, which serves as a slide for the support arm, that holds the enlarging head, which consists of the lamp housing that contains the bulb; a single or double condenser; negative carrier, a place to fix the lens; a means of focusing and lastly a red filter that swings in front of the lens.

The lamp contained in the light housing is of the opal type and has a power output of 75, 100 or 150 watts. The pearlescents of the bulb with the help of a condenser distributes the light evenly across the negative. The lens focuses and projects the negative image on to the baseboard or rather an easel with paper on it. The higher the enlarging head is from the baseboard the closer the lens is to the negative the greater the magnification. The closer the head is to the baseboard the greater the distance the negative is from the lens the smaller the magnification of the picture. The typical focal length of lens for 35mm negative is 50mm and for a medium format (6x6) is about 75mm.
A multi format Enlarger with multi grade head.
Diffuser type.

The negative is clamped in the carrier which incorporates a mask that is the same size or format as the film and then placed in the light box. It is not a good idea to cut the negatives into single frames, it is better to leave them in strips to make it easier to line the frame up with the mask in the carrier, this also means you are less likely to scratched them.


Focusing is usually done manually, although there are enlargers available with automatic focus, these are usually more expensive.