Roll film development by inspection
TIME-AND-TEMPERATURE method described on the preceding pages is a safe, convenient way to process your films—¡f the following conditions are met: I the temperature of the solutions is kept at a fixed level, 2 proper agitation (five seconds every minute) is given, 3 developer strength is maintained at a constant level by use of replenisher, or developing time is in-
creased to compensate for partial chemical exhaustion, and 4 the roll was properly exposed and all frames on the roll are approximately equal in contrast and density.
Eor most of us, it’s rarely possible to control all these factors perfectly. If we develop by time and temperature our results are a mystery until we turn oti the white light, and by that time the
film is in the hypo and it’s too late to correct mistakes. Often enough the best shot on the roll will be the one that was underexposed, and if we had a way of catching this error during development we could turn disaster into triumph. I'his is the reason, the main reason, for development by inspection.
Inspection development need be no more difficult than the time-ancl-tem-
Here are unfaked pictures of what film actually looks like during development
I era t tire method. All it involves is an examination of the film halfwav through the developing cycle to determine howclose to “normal” the emerging image seems to be, and a revision of total developing time is made, il necessary, to correct for any errors that may have (icpt into the photographic process. The film can he removed from the developer sooner than planned il it is overexposed <>r the temperature of the developer has ti sen above normal. The film can he left
in the developer for a longer time than normal il the roll was underexposed, the developer is weak, or its temperature less than normal. Individual frames can he cut from theroll if they need special treatment because they are coining up faster or slower than the rest of the exposures.
I he saleliglu is the kev to inspection development; it provides the illumina-
tion by which the worker may judge his film. 1 his light must fulfill certain requirements. Since most films itt use today are “blind” (insensitive) to light of certain colors, the filter used in the safelight must he of that same color. For example, orthoc hromat ic films likeVerichrome and Plenac hrome are insensitiv e to red. A red light can he left on without danger to the* film during the entiredeveloping process. However, the eye can see quite well under red light, and
with a little practice can learn to judge the density and quality of the image coming up as the emulsion is continuously darkened by the developing action. The other popular film type is panchromatic, including such high-speed favorites as Super-XX, Superpan Press, etc. This type is supposed to be sensitive to light of all colors—and it is—but not to an equal degree. For instance, it is most sensitive to blue and least sensitive
to a dark shade
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of green. In fact, green affects it to such a small degree that a dark-green safelight can be used to inspect pan film while developing action is taking place.
Most of the films in use today fall into either of the above two categories and can therefore be inspected under a red or green safelight. It is worth while, however, to mention two other distinct film types, since by so doing we cover all the kinds made that can be employed in everyday photography.
Commercial photographers and those who work with sheet-film cameras are thoroughly familiar with blue-sensitive or “color-blind” emulsions. These films react to blue, violet, and ultraviolet light only. They belong to the first type of film developed as photography grew up out of the experimental stage. (In fact, it is characteristic of all film and paper emulsions that they are more sensitive to blue, violet, and ultraviolet than they April, 1955
are to other colors.)
The final type, and one perhaps destined to become the most important for many photographers, is hyper-panchromatic, or film which is equally sensitive to all colors. Some of the new extremely high-speed films are almost hyper-panchromatic, and so require great care during inspection to prevent fogging.
Actually, the photographer need purchase only two safelight filters to inspect all the above four types. These are darkred (Wratten Series 2) filter and a darkgreen (Wratten Series 3). These filters are made in all sizes to fit all shapes and types of darkroom safelight lamps. It's not necessary to purchase a complete assembly because the filter for printing can be removed and replaced by the film-inspection filter when needed.
When working with ortho films and a red filter, the entire job can be done with the safelight on. However, this is not true with panchromatic film and its green safelight. Here, the safelight never is turned on until at least 50 percent of the expected total time has elapsed. Even now the film may fog if the light is left on for the total remaining time.
Film manufacturers suggest that the safelight be turned on for a few seconds only. However, a fairly safe rule of thumb is never to exceed about five percent of the developing time. For example, if the total expected time in a particular developer is five minutes, the inspection maximum is about 15 seconds; if the total is 15 minutes, then 45 seconds of inspection at the proper viewing distance will not hurt the film. Of course, if a quick glance at the film is enough to tell the worker what he needs to know, then the light should be snapped off right away.
To prevent fogging the film, the bulb used should not be stronger than 15 watts with the red filter and 10 watts with the green, and the lamp distance from tank or trays should be a minimum of three feet.
The eye is a marvelous light-sensitive instrument. Upon first going into the darkroom, turning off the white light and trying to see something under a dim safelight can be discouraging. But the eye quickly adjusts to the low level of illumination, and when it is fully acclimatized there is more than enough light to see by, for people with normal vision. This adjustment period will vary, depending on how much light was present before going into darkness. At night, the worker may have to wait only five minutes or less before his eyes acquire their maximum sensitivity, but in the daytime as much as half an hour may be required.
“Fogging” or light-streaking is the pitfall to be shunned in inspection development. It can result in a graying over of the entire negative and may then ruin the film completely. However, if the directions given above are followed, this should never happen. Of course, you should also check your darkroom to see that there are no light leaks from outside, since this will fog the film, too. Simply turn oil' all lights earn! sit in the dark for five minutes. After your eyes become sensitive you'll be able to see any leaks.
developers and film
The speed of the film and the characteristics of the developer also have an effect on fogging.
Finegrain developers are slow-acting. Their gentle treatment of the film emulsion is the reason why they produce good texture in the silver deposits that form the image. To get this effect, film speed is sacrificed. To state it another way, any film being developed in a finegrain bath will be slower than if that same film were processed in a more active solution.
This factor has a direct bearing on inspection. The more gentle working developers (Finex-L, Microdol, etc.) will enable the worker to hold up his roll to the inspection light for longer periods without running the risk of fogging it. If the formula used is intended to produce maximum film speed, as is the case with Normadol, D-76, Promicrol, and other vigorous developers, the inspection time must be shorter. The more powerful the developer the more care must be used when inspecting, and an easy way to judge this is by the total time recommended for development. When normal development at 68 F is less than 16 minutes, no more than five percent of the total time should be devoted to inspection, but if the time runs longer than 16 minutes, up to 10 percent will be safe enough. Remember, though, that these maximum inspecting times under a green safelight should not be employed unless absolutely necessary.
The amount of development to which the film is subjected also affects safe inspection time. If the roll turns out to be underexposed when inspected for the first time it should be ducked back into the soup without delay. The longer the film has to develop to make up for underexposure the more likely it is that an inspection light will fog it. This does not mean that a safelight cannot be used, but it does mean that the less time the film remains under the safelight the longer the film can be overdeveloped before log level is reached.
With most developers, if the film is left to develop for a long enough time, even without being exposed to a safelight, fog eventually will appear. However, this occurs way beyond normal developing time and is nothing to worry about during ordinary processing. But when the film is left in the developer for an excessively long time, this chemical fog will occur and be enhanced by safelight fog as well.
Inspection will go smoothly if you make the right preparations beforehand. First make your darkroom safe for inspection development. Cover the bathroom or kitchen window with cardboard or any oilier material that will prevent light from seeping through. If light comes through the door from other rooms it can be made tight by tacking weather stripping inside the wall frame. To check these efforts for complete efficiency, sit in darkness for at least five minutes, as mentioned above. Most photographers who use temporary home setups wait until night when the outside light is practically nonexistent and the artificial light
in adjoining rooms can be turned off.
The tools needed are few in number. The regular items: tank, developer, water supply, thermometer, and timer. Arid to these a stand-by bottle of vigorous developer for emergencies, scissors, and safelight and you’re all set to go. The sink should be the focal point of activity. Immerse the developing tank in water of the proper temperature (68 F ) to insure maintaining the same level throughout development. It's also a good idea to fill the developing tank with solution and bring it to the proper temperature beforehand.
By putting the safelight on a collapsible floodlight stand it can be easily adjusted to hang the proper three feet above the tank. (For a permanent darkroom setup hang it on a drop cord from the ceiling over the sink.) Try to position the safelight so that you don’t have to look directly into it when working at the sink. Looking directly at the filter tends to lessen your eye’s sensitivity in much the same way that looking directly at a light bulb will impair your vision in normal room light. Have the light come from over your shoulder or tilt the safelight slightly so that it faces away, shining toward the opposite wall. (But don’t place it much more than the recommended three feet away or the light will be too dim for inspection purposes.)
All developing operations should be timed, even though the film is inspected. Place the timer where it can be seen by the safelight illumination. Of course, the cover could be placed on the tank once it’s loaded, and the white light turned on, but this would interfere with your carefully acquired eye sensitivity. Also, remember that about 100 percent overdevelopment is about the limit for most developers. Beyond that point, excessive chemical fog is almost sure to result.
The type of tank used is of relatively little importance, since inspection is no more difficult with the adjustable, plastic kind than it is with the fixed-size metal type. With the sink water at the correct temperature and at a comfortable level so that the tank will not float when placed in it, the safelight located three feet above the sink and facing down in such a manner that the light does not shine directly into your eyes, and the timer, developer, and fixer all within easy reach, the white light is turned off and the film is loaded onto the reel. Never turn on the safelight to load the tank. This may be a temptation because of its convenience, but any green light reaching the film at the first stage of development may cause severe fog.
Developing procedure is the same as for time-and-temperature. The reel is placed in the tank, developer is added (unless the tank already is filled), and the timer is turned on when the tank is full. Agitate continuously during the first 15 seconds to prevent the formation of air bubbles between the surface of the film and the solution. After that agitate for five seconds every minute. Once the cover is placed on the developing tank you can turn on the green safelight, thus April, 1955
permitting you to check the passage of time on the clock.
After half the anticipated developing time has passed, turn oil the inspection light, remove the tank cover, and lift out the reel. Pull the outside end of the film loose from the reel and unwind to expose a few frames. Now turn on the inspection light and view the developing progress to date.
The film should be inspected by reflected light. That is, look at the surface of the emulsion, just as you view the
final print, not through it, as you view a completed negative. The opaque film backing is still present at this stage, making it difficult to see what’s happened if you try to look through the emulsion.
What should you expect to see? The five accompanying illustrations showing five different steps of development will give you some idea. At half-time, a substantial image should have formed. If, when the emulsion side is held up to the light, it appears that there are only faint signs of a picture, the film is very underexposed and should be switched to a more vigorous developer. If the image is very black and solid looking, it is overexposed and should be removed at once. A final check of this latter point is provided by turning the film over and looking at the backing side. It will appealwhite and opaque, but if the image is fully developed, bold traces will show through.
In most cases, inspecting about onethird of the roll will be enough. However, when you suspect that exposures are uneven, the roll can be unwound further, taking care not to pull it off the reel altogether. Rolling film back on the reel is easy if the edges of the film are gently squeezed while the reel is rotated.
But this is clone in the dark. Use the safelight only when you’re actually inspecting with it. The inspected film then should be returned to the tank and agitated for 15 seconds continuously to make up somewhat for the time it was held out of the developer.
If inspection shows that one or more frames are underexposed and will be ruined if developed to the level of the
rest of the roll, the scissors should be used to cut out the underexposed frames. It’s a good idea to keep your standby energetic developer in a tray, since short film strips cannot be replaced in a tank. Rinse the film strips in running water first before transferring from one type of developer to another.
If inspection shows that one or more frames are overexposed, these can be cut off the rest of the roll and dropped into a waiting tray of hypo.
The remaining portion of the roll can be given whatever treatment is necessary. If normal, carry out development to the recommended time, rinse in the usual way, and fix. The strip getting “dynamite” treatment in fast developer should be given a quick check under the safelight every few minutes to determine when it is done.
Tray development is necessary when tanks are not available for rolls or sheet film. It is a little more awkward to use trays for the reason that the film must be agitated continuously to prevent sticking, when several sheets are processed at once, or to guarantee that rolls are bathed evenly in the solution by methodically running them back and forth through the solution.
The water-filled sink still is the focal point of activity. Set your trays on either side of it: developer on the left and hypo on the right. Place a thermometer in the corner of the developer tray and check
it frequently for temperature. If after processing one roll the solution has grown warmer or cooler than 68 F, it should be brought back to the proper temperature before any more film is put through it. When using a finegrain developer it is still a good idea to have a second tray of more active developer in readiness to save any frames or completed rolls that are badly underexposed. In all other respects the tray developing routine is no different from the method described above for tank processing. Again, the green light should not be turned on for the inspection of panchromatic films until half-way through developing time, but ortho films can be processed by a red safelight left on continuously.
Different sizes of films appear different when viewed under a safelight. The darkest looking of them all is 35-mm. This occurs because the image is condensed into such a small area. Under the inspection light, a normally developed 35-mm negative will look solid and opaque, almost black. Roll films look less dense because of the larger image size, and details are easier to see. Film packs resemble roll film in appearance, while sheet films, with their heavy acetate base, tend to look somewhat solider and blacker. The only way to learn what a normally exposed and developed negative looks like under the safelight is to develop by inspection, not once, but repeatedly. While you’re gaining the necessary experience you’ve still got the timer to fall back on in case of doubt.—feet