Ilford SFX 200 Black and White Negative Film (35mm Roll Film, 36 Exposures) User Manual
Page 2
Page 2 of 6
Nov 2018
SFX 200
Technical Information
USE OF FILTERS
SFX 200 film can be used with yellow, orange or red filters, but the effect seen will depend on its transmission
characteristics. The redder the filter, the more dramatic the effect. With very dark filters, exposure times can be
very long, so the use of a tripod is recommended. Below is a guide to filter factors for various filter colours.
Filter Factors
Filter
Kodak Wratten
(or equivalent)
Filter Colour Filter
Factor
Exposure
Increase (Stops)
3
Very Light Yellow
2
1
8 Yellow
2
1
⅓
12 Deep
Yellow 2.3
1
⅓
15
Very Deep Yellow 2.4
1
⅓
21 Orange
2.4
1
⅓
23a Reddish
Orange
2.5
1
⅓
25 Red
2.8
1
½
29 Deep
Red 3
1
⅔
89B Very
Deep
Red
16
4
LOADING THE CAMERA
SFX 200 must be loaded in subdued light. Unlike true infra-red film, it is not necessary to load it in total
darkness.
FOCUSING
With some lenses, red light focuses at a slightly different point to other visible light. With these lenses, there
may be a shift when focusing in white light compared with red light. However, it is almost impossible to focus a
camera with a deep red filter in place.
With short to moderate focal length lenses, this difference can easily be accommodated by stopping down to
the smallest working aperture. Some lenses, particularly apochromatic (APO) designs, may need no correction.
EXPOSURE
A certain amount of experimentation is needed when first using this film. As a guide, bracket exposures by +/-
2 stops from the TTL reading with the filter in place, or the meter reading with the filter factor applied.
Note
The TTL metering on some common cameras can under expose by up to 1 1/2 stops with deep red or
orange filters in place.
If you want to check the TTL metering system on your camera before starting, set the metering system of the
camera to EI 200/24, and with your filter in place – make a series of exposures up to
±
2 stops from the
indicated exposure. After processing, decide which is the best negative and re-set the camera if necessary. As
an example, the correct exposure in bright sunlight with a deep red filter is around 1/30
th
second at f5.6.
CHARACTERISTIC CURVE
SFX 200 film developed in ILFORD ID-11 stock for 10 minutes at 20ºC/68ºF
with intermittent agitation.