Post by Steaphany on Jun 27, 2013 16:09:39 GMT
Now that you have a negative, lets evaluate it.
Adapted from Kodak's "Black-and-White Tips and Techniques for Darkroom Enthusiasts" Publication O3, 2002 and from the "Photographer's Mate 2 & 3", Bureau of Naval Personnel, Rate Training Manual, NAVPERS 10355-A, 1971 Edition
A negative has several characteristics to be considered when evaluating it's quality. These include gradation, tone separation, density, contrast, grain, etc. It is not hard to determine what condition produced an error and thus learn how to avoid poor negative quality in the future.
Density
Density determines how much of the incident light falling upon the negative passes through the image. If very little Silver is present in the negative, the image appears thin ( transparent ) and it is said to have a low density. If there is a large amount of Silver present, very little light passes through the image, and the negative is said to have a high density, or it may be called a heavy or even a dense negative. However, average or normal density varies considerably according to the method used to make prints from the negative. Thus a dense negative is more easily printed by contact than by projection; whereas, a thin negative is much easier to print by projection than by contact.
Highlights
The highlights or dark areas of a negative for most purposes should not lack detail. If any detail is missing, the highlights are termed too dense, choked up, or blocked out. The detail is missing in both the highlights and shadows if the negative is thin.
Shadows
The shadows or the more transparent areas of the negative should also contain detail. If these areas are so thin and weak that the outlines of the subject are lost, the shadows are termed lacking in detail or blank.
The need of detail in both the highlights and the shadows for photographs of most subjects cannot be stressed too strongly. One is just as important as the other in the production of good photographs.
Contrast
Contrast is the difference in density between the highlights and shadows. A negative has a good level of contrast if the lightest and darkest areas still retain sufficient detail. Note that some developers, D-23 for example, particularly when used in a 1 to 1 or 1 to 3 dilution with water, will preferentially develop the shadows faster than the highlights. This compresses the dynamic range and lowers the contrast and can be useful when needing to capture a scene with a large variation in light levels.
Due to the obligations of life, I'll have to add more later, keep coming back to see what I add.
Adapted from Kodak's "Black-and-White Tips and Techniques for Darkroom Enthusiasts" Publication O3, 2002 and from the "Photographer's Mate 2 & 3", Bureau of Naval Personnel, Rate Training Manual, NAVPERS 10355-A, 1971 Edition
A negative has several characteristics to be considered when evaluating it's quality. These include gradation, tone separation, density, contrast, grain, etc. It is not hard to determine what condition produced an error and thus learn how to avoid poor negative quality in the future.
Density
Density determines how much of the incident light falling upon the negative passes through the image. If very little Silver is present in the negative, the image appears thin ( transparent ) and it is said to have a low density. If there is a large amount of Silver present, very little light passes through the image, and the negative is said to have a high density, or it may be called a heavy or even a dense negative. However, average or normal density varies considerably according to the method used to make prints from the negative. Thus a dense negative is more easily printed by contact than by projection; whereas, a thin negative is much easier to print by projection than by contact.
Highlights
The highlights or dark areas of a negative for most purposes should not lack detail. If any detail is missing, the highlights are termed too dense, choked up, or blocked out. The detail is missing in both the highlights and shadows if the negative is thin.
Shadows
The shadows or the more transparent areas of the negative should also contain detail. If these areas are so thin and weak that the outlines of the subject are lost, the shadows are termed lacking in detail or blank.
The need of detail in both the highlights and the shadows for photographs of most subjects cannot be stressed too strongly. One is just as important as the other in the production of good photographs.
Contrast
Contrast is the difference in density between the highlights and shadows. A negative has a good level of contrast if the lightest and darkest areas still retain sufficient detail. Note that some developers, D-23 for example, particularly when used in a 1 to 1 or 1 to 3 dilution with water, will preferentially develop the shadows faster than the highlights. This compresses the dynamic range and lowers the contrast and can be useful when needing to capture a scene with a large variation in light levels.
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Negative Defects, their Appearance, Cause, and Remedy
Defect | Appearance | Cause | Remedy |
| Abrasion marks or streaks | Fine black lines usually resembling pencil scratches running in the same direction | Friction on emulsion caused by improper handling or storage sometime between manufacture and developnment | Great care should be taken in the storage of film.Boxes of film should be stored on end so that no pressure is exerted on the surface of th emulsion. Care should also be taken not to rub or drag sensitized material over a rough surface, before or after development. |
| Air bells | An air bell occurring during development shows as a small transparent spot. Sometimes minute, dark streaks lead from the spot.When a negative is rocked in a tray, streaks project from the spot on each side of the spot in the direction the tray way rocked. If the tray is rocked in two directions, the streaks form a cross with the spot in the center. In tank development, the dark streak usually form at the lower edge of the transparent spot. In the fixing bath, they show as small round dark spots. | Transparent spots occurring in the developer are caused by bubbles of air on the surface of the emulsion. Darkened streaks are the result of excess oxidation of the developer, caused by the air in the bubble. Dark spots which occur in fixing bath are the result of an air bubble holding fixer away from the emulsion allowing a slight continuation of development. | Immerse film carefully and thoroughly in the developing and fixing solutions. Move and agitate the film for the first 30 seconds to ensure any air bubbles have been dislodged. Alternatively, employ and pre-soak with water to ensure a properly wetted emulsion surface. Water always contains some air and when there is a rise it temperature, air isexpelled and gathers in the form of small bubbles on the surfaces of the tank and film during the preliminary stages of development. Allow processing solutions and water needed for development to stand for at least several hours at the processing temperature prior to use. |
| Blisters | Resemble familiar blisters which arise on human skin after a burn. | Emulsion blisters for when either a liquif or gas accumulates between the emulsion and the film base when solutions are too warm and loosened the gelatin from it's support. Blisters are also possible when either the developer or fixer are too strongly concentrated. Changing the film from one bath to the next may cause the formation of gas between the emulsion and the base, frequently caused by insufficient rinse after development and placing the film directly into a fixer with a strong acid content. Another common cause is allowing tap water to flow from the faucet directly only the emulsion. | Description of causes of blisters indicates the manner in which defects can be avoided |
| Blurred Negative | Indistinctness or lack of definition in the negative image. | The subject is not properly focused on the film; movement of the camera or subject during the exposure; or lack of proper camera adjustment, film was not flat in the focal plane when the exposure was made. Sometimes produced by moisture, hase, or dirt on the lens. | Care in focusing and holding the camera, keeping the camera in proper adjustment and the lens free from moisture and dirt. |
| Brown stops | Brown or sepia colored smallareas or spots on the negative | Produced by oxidized developer or by fine particles of chemicals settling on film prior to development. May also occur during washing, from rust or other impurities in the water. | Avoid exhausted or oxidized developer. Do not use darkroom for mixing chemicals. Filter wash water. |
| Crystalline surface | Surface of negative emulsion possesses crystalline appearance suggesting frost on a window pane. | Insufficient water rinse after fixing. Hypo remains in the film and srystalized. | Ensure sufficient final flowing water rinse |
| Dark lines | There lines must be divided into two distinct classes - those which run from dark areas to more transparent areas of th negative, and those from more transparent areas to darker areas. In both cases lines are wider, not as clean cut, and not nearlt as parallel as abrasion marks. | First class is caused by insifficient agitation of the negative during tank development. Cause of the second class is thought to be of electrolytic origin. | For first class, more frequent agitation during development.Remedy for this class aggravates defect in second class. Only known remedy is to remove all film hangars from tank four or five times during developing period. holding hangars in a bunch, and allowing corners of hangars to rest on edge of developing tankfor 10 to 15 seconds. |
| Fading Tendency | Sepia or yellow colored stains or areas in negative | Incomplete fixation, or insufficient washing will cause fading. Remnants of fixing bath left in emulsion continue their action and in time this defect appears. | Properly fix and wash negative completely. Final washing is as important as any operation in negative processing. Consider following the foxing bath with a Hypo Clearing bath. |
| Fingermarks | Imprint of fingers shows up on negative | Impressing wet or greasy fingers on emulsion of film febore or during develipment and fixation. If mark is mearly an outline of finger, it was caused by water or grease on finger. If dark it was caused by developer; and if transparent or light, it was caused by fixing bath. | Keep hands clean and dry when handling film. Sometimes natural oil on fingertips causes grease marks referred to above. Handle film by edges. When gingers become wet with water or solutions wash and DRY THOROUGHLY before attempting to handle film. |
| Fog ( Aerial ) | a slight veiling negative or parts of negative | Negative exposed to air during development, especially when hydroquinone is used as a developing agent. Occurs most frequently in freshly mixed developers, particularly those containing excessive amounts on alkali or hydroquinone. | Add Potassium Bromide to developer or a small quantity of used developer to fresh. |
| Fog ( Dichroic ) | Usually a fog of little density, consisting of finely divided particles of Silver. When viewed by transmitted light it is pinkish; viewed by reflected light , it appears reddish-green. | Using Ammonia as an accelerator. Fixer or excessive amount of Sulfite in developer. | Easily treated by treating negative in a weak solution of Potassium Permanganate. Prevention is obvious from list of causes. Further prevention is assured by using clean tanks for developer and fixer solutions. |
| Frilling | Edges of gelatin become detached from base. Detached edge of emulsion may either break off or fold over. When latter happens, it is sometimes possible to partially remedy damage by smoothing out emulsion when negative is placed to dry. | Careless handling; using solutions that are too warm; insufficient hardening of emulsion due to insufficient fixation; exhausted fixing bath or one containing insufficient amount of hardener; and/or excessive washing. Frilling is usually caused by a combination of careless handling and any other mistake that will render the emulsion of film soft. | Handle film carefully and sparingly; use working solutions that are mixed correctly and are at proper temperature. Wash film thoroughly, but never excessively. |
| Gas Bells | Minute pimples or blisters | Develop by transfering negative from strongly concentrated developer to a strongly acid fixing bath without thoroughly rinsing, after removing from developer and before immersing in fixing bath. In warm weather, gas bells may appear even when using solutions of normal strength, if rinsing between development and fixation has been insufficient. | Use an intermediate hardener/rinse bath. |
| Halation | A dark area or band extending from intensely bright objects, suggesting a double image, and appearing in print as a halo or band of light around object | Photographing an intensely bright object surrounded by dark objects. Intense light penetrates emulsion and is reflects back by film base. | Use antihalation film ( I have never seen a film lacking an antihalation layer ) and avoid pointing cameras at bright sources of light. |
| Pit marks | Fine holes or pits in the emulsion | ||
| Pinholes | Minute transparent spots | ||
| Reticulation | Leatherlike graininess or wrinkling of emulsion | ||
| Streaks | Streaks or patches, as in the case of spots, may be dark, white, or transparent. | ||
Due to the obligations of life, I'll have to add more later, keep coming back to see what I add.