Related theory for the Preliminary Course covers darkroom and film developing processes, SLR camera’s and related practices and the history of Photography.
Darkroom theory has been covered on the Darkroom page.
Information here will be course specific in nature.
- Film development work-flow = Developer > Stop bath > Fixer > Wash > Flow agent > Dry
- Paper development work-flow = Developer > Stop bath > Fixer > Wash > Dry
Chemical ratios and times
- Developer ID11 1+3 for 20min @ 20 deg Celsius
- Stop 1+40 for 30 seconds
- Fixer 1+4 for 2 minutes
Resin Coated Paper
- Developer 1+9 for 1 minute @ 20 deg Celsius
- Stop 1+40 for 30 seconds
- Fixer 1+4 for 30 seconds or 1+9 for 1 minute
Fixer @ Ilford.com
For an in-depth read see Print Processing Chemicals
If the temperature of your water is above or below 20 degrees Celsius consult your temp chart and make the appropriate adjustment.
image @ www.covingtoninnovations.com
For an overview of the steps involved in loading film into a developing tank using a lightproof bag click here
For an overview of printing processes click here
- Being able to evaluate your negatives to correctly determine whether they are underdeveloped, overdeveloped, correctly developed, underexposed, overexposed or correctly exposed takes accumulated experience. However good visual guides are available. Evaluating your Negatives is a good place to start.
- Developer becomes exhausted through usage and contact with air. Exhausted developer will turn a dark brown and developer that is saturated with silver bromide will appear greenish under safe lights.
- Stop Bath is self indicating and will turn a purple or bluish colour when exhausted.
- Fixer is harder to determine. Usually the best way is to take a piece of unexposed film and place part of it in the Fixer tray. If the film does not clear within one minute then it’s most likely that the Fixer is exhausted.
All SLR cameras contain the same components, of which the most commonly identified are;
Of these the inclusion of film as a camera component is the only issue of contention simply because film is added to the camera to take exposures wheres all the other components contribute to the functionality of the camera whether film is present or not.
A good interactive graphic for this can be seen here
To correctly expose film in the camera light must strike the film plane for the correct amount of time. The factors that influence this are;
- The aperture setting which determines the amount of light entering the camera.
- The shutter speed setting which determines the amount of time that light falls on the film plane.
Exposure calculation is in full the combination of Film ISO + Aperture + Shutter speed.
Film Speed Ratings
All film has a ‘speed’ or light sensitivity rating.
- Film with an ISO of 50-200 is characterized as SLOW because it has a finer grain structure and is therefore less sensitive to light.
- Film with an ISO rating of 400+ is characterized as FAST because it has larger grains of silver halide (coarse grain structure) and is more sensitive to light.
- ISO stands for International Standards Organization and came into being in 1974 when the film standards ASA and DIN were combined.
ASA and DIN equivalence table @ www.japancamerahunter.com
- ISO ratings increase in one stop increments e.g., 50-100-200-400-800-1600-3200 etc. Each increase doubles the light sensitivity of the previous.
- Slow film is best suited to situations where light is plentiful, strong or harsh and where you want a print that has little or no visible grain.
- Fast film is best suited to low light situations e.g., late afternoon, heavy overcast skies, indoors, situations where there is little available light and of course at night.
The aperture in a camera performs a number of functions. Firstly it determines the size of the incident beam passing through the lens.
Aperture diameters are measured in f stops. An f stop is the ratio of the focal length of the lens to the diameter of the aperture pupil / opening.
image @ blog.pedromendes.com
- The Aperture also controls ‘depth of field’ or ‘zone of focus’ This effectively means that as the aperture decreases in size the depth of field increases and visa versa. For example @ 50mm with a focus distance of 3m at f1.8 the DOF is .37m, at f2.8 DOF is .6m, at f4 DOF is .86m, at f5.6 DOF is 1.25m, at f8 DOF is 1.84m, at f11 DOF is 2.86m, at f16 DOF is 5m, at f22 DOF is 13.4m at f32 DOF is infinite.
Graphically DOF core concepts could be represented like this:
image @ easy-exposure.com
- Related to Depth of Field is Hyperfocal Distance. Hyperfocal distance refers to the area of acceptable sharpness in an image. There are two standard definitions for this and these are;
1: The hyperfocal distance is the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp. When the lens is focused at this distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp.
2: The hyperfocal distance is the distance beyond which all objects are acceptably sharp, for a lens focused at infinity.
So coming back to the previous examples @ 50mm with a focal distance of 3m at f1.8 Near Hyperfocal is 23.4m Hyperfocal is 46.8m and far Hyperfocal is infinity, at f5.6 Near Hyperfocal is 7.3m Hyperfocal is 14.7m and far Hyperfocal is infinity and at f16 Near Hyperfocal is 2.9m Hyperfocal is 5.8m and far Hyperfocal is infinity. So what you can see here is that as the Aperture closes down Near Hyperfocal and Hyperfocal distances move closer to the camera.
The aperture of a camera has qualities similar to the human eye
image @ Betweens
The shutter determines the amount of time / duration that light is on the film plane. Shutter speed is balanced with the aperture setting to control exposure. Variables in the shutter speed also give the photographer control over whether a subject in motion is blurred or in sharp focus.
Shutter speeds are measured in increments that can range from 1/3rd of a stop to a whole stop. The increments in bold in the image below are 1 stop increments i.e., the shutter speed doubles with each increment.
Another graphic depicting the influence of aperture and shutter speed on exposure
image @ jessicalouisebell.wordpress.com
Understanding Focal Length and Field of View
The principle here is fairly straight forward. The shorter the focal length of the lens the wider the field of view and conversely the longer the focal length the narrower the field of view.
Focal Length is represented as such
How the relationship between Focal Length and Field of View looks graphically can be demonstrated as follows.
The physical relationship between focal length and lens build is also fairly evident.
Zoom lenses are typical in the sense that the lens diameter has to increase to compensate for aperture equivalency across a range of focal lengths.
With Prime lenses or ‘fixed focal’ lenses a shorter focal length does not necessarily mean a shorter lens barrel as the example below demonstrates.
image @ lovethatshot.com
Identifying image types
By definition a telephoto lens is a lens constructed so as to produce a relatively large image with a focal length shorter than that required by an ordinary lens producing an image of the same size: Used to photograph small or distant objects.