Tuesday, September 03, 2013

Black And White Printing Flters

Black and white printing filters make it possible to increase or decrease the number of gray tones in a print. This is referred to as changing the contrast of the print. They are manufactured by Kodak and Ilford. A set suitable for 35mm printing is ~$20. It is important to make sure to get the right size for the enlarger being used. For most 35mm enlargers the size is 3.5".

The filter is placed in the filter drawer. The filter drawer is above the negative carrier and above the condenser lens On an Omega C700, it is where the Omega name appears. Pull the tab and a small drawer pulls out. Place the filter in this drawer. With some enlargers it will be necessary to carefully cut the filter to reduce it to a size suitable for the filter drawer. Cut it very carefully since filters are sold only as full sets.

By carefully looking at a black and print, it can be seen that most black and white prints have a jet black area, a paper base white area and one or more gray areas of varying darkness.

1 Make a print without any filter.
2 Make a second print using a printing filter. Each new filter will require a new test strip.

Choose the filter as follows.

If the print is too gray try a #4 filter. If the print needs more gray try a #1 filter.

3 Carefully compare the first and second prints. This should be done slowly and in the brightest light available.

4 If the second print made with the #4 filter is still too gray try a #4 1/2 filter. If it has become less gray than desired try a #3 1/2 filter.

If the second print made with the #1 filter is still not gray enough, try a #1/2 filter. If it has become too gray try a #1 1/2 filter.

5 Compare all three and adjust accordingly in 1/2 step increments.

The Ilford filter set offers the following filters

#1 1/2
#2 1/2
#3 1/2
#4 1/2

Occasionally the filters will not give the desired contrast range making it impossible to print the negative. Problem negatives are those that are extremely light or extremely dark. Film has a greater range of tones than paper making it impossible to print everything that is visible in the negative.


Post a Comment

<< Home