Photography, Darkroom and Chemistry Information
From Silvergrain Labs
Contents |
Photosensitive materials
Silver halide photography uses materials such as dry plate, film, and photographic paper. These are the distiction based on the physical support, but they use different kinds of emulsions, as described in emulsion. These materials come in different dimensions.
Typically, a plate or film is exposed in-camera to make a negative image, and this is reversed by printing on printing paper by contact printing (1:1 reproduction size) or projection (arbitrary reduction or magnification), to make the final positive image. This is called negative-positive sysem. Most modern practice uses medium to fast negative film in camera, and enlarging the negative by projecting the image.
Printing out and Developed Out Processes
- printing-out processes (POP)
- Image is printed out by intense exposure
- developed-out processes
- Image is exposed and then made visible by a developer
Conventional silver-gelatin process, collodion process (used for wet plates) and Calotype (of Talbot) are exposed to make invisible latent image, and then developed to form visible image. These are called developed-out processes. Because the developer chemically amplifies tiny latent image centers to image-forming silver grains, developed out processes generally exhibit greatly enhanced light sensitivity compared to non-developed counterpart.
Hand Crafted Material
Most, if not all, of these processes are currently practiced by fine art photographers. The sensitizing solution is prepared and coated on suitable substrates, often unsized paper or gelatin sized paper.
Processing
Exposed materials are processed in (1) developer, (2) stop bath, (3) fixer, and then (4) washed, and (5) dried, in this sequence, sometimes with auxiliary processing (such as presoaking, washing aid, bleaching, intensification and toning) in between or following these steps. A wetting agent is often applied to the film before drying. Processing chemistry of films and papers are analogous, but different stocks of chemicals are often used for film and paper, especially for the developer, to accomodate the differences in these materials.
Processing chemicals are often reused by allowing longer processing time for fatigued solution, or more preferrably in Replenishing system.
Print materials are usually processed in dish, but they can be processed in vertical slot processors or rotating drums. Replenishing system works well in slot processors.
Chemicals
If you are going to take advantage of information provided in this website, you'll need to find chemical suppliers. If you are a serious in photographic technology, a decent laboratory chemical supply house is essential. If this does not work out (they do not ship to most private addresses), your best bet is photographic chemical suppliers, or take advantage of this link: Survival Chemicals and links therein. Also see water.
Print Developer Recommendation Film Developer Recommendations Film Developer Comparison Ascorbate Developers glycin chlorhydroquinone D-76 Dilution Japanese Developers Lith Printing pH A booklet on Kodak Fine Line developer by T. R. Hearsum, 1975.
Darkroom Equipment
Durst Laborator 138: A classic 5x7 enlarger. Durst M601: A compact 35mm and 6x6cm enlarger. Air Conditioner
Darkroom Safety, Environmental Concerns and Harmless Photo Chemistry
The most important safety measure is training of proper handling of darkroom chemicals. It is also important to equip darkroom with necessary safety equipment. If you don't get exposed to the chemicals, and dispose of the chemical properly, most darkroom chemicals are nothing to fear about.
However, there is an effort to replace commonly used hazardous compounds with safer alternatives. See Nontoxic darkroom chemicals, which describes how toxic or harmful chemicals (including environmentally harmful chemicals) can be removed from photographic chemicals. By taking such approach, potential risk to darkroom workers and the environment can be minimized, in case of accidents during transportation, mixing/preparation, darkroom work, or waste disposal process. Environmentally friendly chemicals are also better in case the unused or waste chemical is accidentally released to the environment. In the link above, it is described that safer chemicals can be formulated by avoiding chemicals like hydroquinone, borates and EDTA, all of which are very commonly used. Alternative compounds are also discussed, so that excellent image quality can be obtained with increased safety to the humans, animals, aquatic animals and plants.
Archival Concerns
Important images should be handled with conservation in mind. When handling important old materials, the approach is usually to (1) make high quality duplication images; (2) ensure ideal storage conditions; and other means, largely passive ones. However, if you are an original artist preparing important work, you can approach this issue more proactively by following archival processing guidelines and also following the conservation guidelines for storage conditions.
archival process conservation residual thiosulfate tests wash washing aid toning
Camera and Shooting Style
Camera Accessories Konica Autoreflex T Konica SLR
Sekonic L-208 light meter on TLR's
Konica Hexar (AF model, Black and Silver)
Konica Auto S2 (a rangefinder camera with Hexanon 45mm f/1.8)
EOS 600 series (620, 630, 650)
Horizon Perfekt (a true swing panoramic camera)
Framing, Display, Scanning, Image management
Organizing Images
I keep record of negatives on this negative record form (PDF), and keep it with the negative file (contact print file). I also keep record of printing, especially the details of burning/dodging on a printing record form (PDF) and keep it with the contact print in a clear plastic file.
History of Silver Gelatin Process
Other Resources
Encyclopedia of Twentieth Century Photography, Routledge, 2005 This author contributed 4 entries in this encyclopedia.
Photographic Resource Center at Boston University
