DEVELOPING THE PHOTOGRAPHIC NEGATIVE

most people know something about photographic prints they know that a photograph is a reproduction of things in terms of light and shade things that are light in nature are light in the print those that are dark in nature are dark in the print a lot of people even know something about photographic negatives and that they differ from Prince things that are light in nature are dark in the negative and those that show light in the negative are dark in nature in other words the tones in a negative are reversed from those in nature but a good photographer must know a lot more about negatives than that first of all he must understand what happens when a plate or film is exposed in making a photograph of objects in a scene he must know something about the behavior of reflected light for our study of reflected light we are using a simple subject a pyramid lighted by a single lamp placed so that more light falls on one side of the pyramid than on the other that's what makes one side appear lighter in tone than the other some of the light falling on the pyramid is reflected toward the camera lens the reflected light from the lighter side has a greater intensity than the reflected light reaching the lens from the darker side when we open the shutter reflected light from the subject is gathered by the lens and focused on the film where an image is formed which is inverted and reversed the light of which the image is composed affects the sensitive emotion of the film to get some idea of what happens in the film's emulsion under the action of light let's study a greatly magnified cross section of a photographic film here are the silver halide particles as revealed by a powerful microscope in total darkness that is with the shutter closed so no light gets to the film the silver halide particles in the emulsion are on affected we might say that they are asleep when the shutter opens the light penetrates the emotion and strikes the silver halide particles and those which the light reaches wake up the greater the intensity of the light striking the emotion and the longer the exposure the deeper it penetrates and the greater the number of particles that are awakened when we close the shutter light no longer penetrates the emulsion all the little particles remain as they were when light ceased to reach the emotion the ones that were awakened stay awake those not reached by the light remain asleep now it must be clearly understood that as yet there is no visible change in any of the silver halide particles if we take a piece of film and look at it as light falls upon it we can't detect any change taking place even though the light here is thousands of times as much as would reach the film to make a normal exposure in a camera however the action of light always produces a latent image that is an image which lies dormant within the emulsion and which cannot be seen until it is brought into visible form by chemical means the process of bringing the latent image to life is called developing how do you go about this job of developing if you have more than two or three negatives to develop you will find it an advantage to use tanks you'll need at least four one of the tanks is for developer this is where the latent image comes to life another tank is for rinse water here's where you rinse off the films to remove developer after they have been developed the third tank is for the fixing bath where the developed films receive a treatment which fixes the image that is which makes it permanent the fourth tank is for washing the film the names of the chemicals used in the processing of films are given in your instruction manual also how they should be mixed and the temperature at which your solution should be used now for the actual developing procedure if you have 12 films to process use 13 film hangers with the extra hanger you can check the level of the solutions in the tanks check the level of the developer first if the film holding bar does not completely submerge the level is too low so add replenish sure to assure that the films will be completely immersed then check the level of the rinse water then that of the fixing bath now wash the chemicals off so that if the hanger is used some time later to hold a film for development it won't contaminate the developer it's very important to check the temperature of your solutions particularly the developer the temperature should be held to within a degree or two of 68 degrees Fahrenheit set your timer development should be for the time that is specified for a particular type of developer some films must be developed in total darkness others can be processed under a safe flight with everything in readiness turn off the room lights to be able to photograph the scenes in the darkroom we will have to use more light than that from the safelite but remember that this is done only so that you can see the actions that will be portrayed after the film has been removed from the holders load the hangars handle the film carefully by the corners and edges avoid putting your fingers on the surface of the film fingerprints are valuable as identification but they add nothing when they show up in a photograph there they reveal evidence of sloppy darkroom work the holding bar should be snapped into place so the films will not slip out of the hangars now put the loaded hangers into the developing tank start the timer work the film's up and down gently this helps to get the developer evenly over the surfaces of the films and reduces the possibility of air bells now while the films are developing let's look into some facts about the developer what it is and how it works- developers are made from several different chemicals the chemicals are mixed in exact proportions each in the exact amount that will assure a properly acting developer and dissolved in a specified amount of water let's first consider these two chemicals me tall and hydroquinone they are frequently combined to make the familiar mq developer a developer is called a reducer because its action is to reduce the silver halide salts in the emulsion to blackened particles of metallic silver the reducer is most commonly used in photography will work only in an alkaline solution so a second chemical usually sodium carbonate is added to make the solution alkaline this is called an accelerator but the carbonate causes too vigorous in action so a restrainer goes into the solution the restrainer usually potassium bromide gives the control required to make both the reducer and accelerator perform as we want them to the reducer accelerator and restrainer are not enough we must add a preservative to keep the solution from oxidizing the effect of oxidation is to weaken the developer and to cause chemical fogging of the emulsion the preservative most commonly used is sodium sulfite these four basic chemicals in specified proportions make up the developer better to understand how they work together as a team and to help you remember what they do let's compare their action with some mechanical principles with which we are all familiar gasoline by itself alone would make an automobile engine run neither will the reducer by itself alone make a developer perform the gasoline needs air to make it produce power air mixes with the gasoline in the carburetor and this mixture is admitted to the engine in varying amounts as you press your foot down a little or a lot on the accelerator the action in the engine is the mechanical equivalent of the chemical action of the accelerator in the developer but too much acceleration whether in an automobile or in a developer is dangerous so the amount of acceleration must be controlled by limiting it to a safe value to restrain the action the brakes in an automobile may be compared to the chemical restrainer used in a developer the automobile needs oil to keep it from wearing out a developer needs to be kept from rapidly wearing out and that is done by the chemical preservative let's return to the darkroom and take a look at the films which have been developing under the dim light of the safe lamp you can see the image beginning to show now let's look at a greatly enlarged cross-section of a film and see what the developer does as the developer slowly works into the emotion it causes it to swell but the film base is not affected the developer reduces the awakened silver halide particles to blackened metallic silver particles the unawakened silver halide particles are not changed in any way by the developer a small number of the particles affected by light may not be reduced by the developer but this is unimportant the vast majority of affected particles have been reduced and we have a negative that has reached the state of complete development when the timer signals you then you raise the hangers from the developer and let the solution drain off their corners next place the negatives in clear rinse water of the same temperature as the developer move them up and down several times to remove as much as possible of the developer to keep the fixing bath from contamination by the developing chemicals if this is not done the fixing bath will soon wear out furthermore there will be a more gentle reaction on the negatives by the fixing bath if most of the raw developer is rinsed off first in the fixing bath the fixing agent works into the emotion it dissolves all the particles that were not reduced to metallic silver by the developer this includes even those particles that were awakened by the light but not reduced when the film is placed in the fixing bath the emulsion has a milky appearance which gradually disappears as fixing continues when the film has cleared up and the milkiness has disappeared half the required fixing time has passed in other words the time required for fixing is just twice the time from the start of fixing until the milky appearance has cleared up a film that clears up in five minutes will be completely fixed in ten minutes when fixing is complete only the blackened metallic silver particles which form the image remain but the emulsion is saturated with fixing agent and this must be removed by thorough washing the hangers are removed from the fixing bath draining off the excess back into the tank adjust the water flow and set the timer for the length of time which has been established for thorough washing now let's see what the washing does when the film is put into the wash tank water begins to soak into the emulsion and dilutes the fixing agent with which it is saturated the molecules of fixing chemicals slowly wash out of the emulsion and when they have been removed from the emotion the film is completely washed extra washing is unnecessary and may in fact cause the gelatin emotion to swell excessively and perhaps to break down when washing is complete lift out the hangers and let the excess water drain off remove each film from its hanger and carefully wipe it with a moist sponge to prevent large droplets from forming on its surfaces put a clip on each film at the edge in one corner or in the short side hang them in the drying cabinet observe this the drying cabinet is used only to remove the excess moisture not to heat the film so if you use a drying cabinet that has facilities for heating the air be careful don't let it get too hot not over 100 degrees Fahrenheit so check your cabinet see that the ventilating switch is on so there'll be proper air circulation when they have dried your work on the negatives is complete careful attention to detail at every step assures negatives that will yield good prints negatives of which you will be proud