Photomacrography with the Polaroid MP-3

(Modified from directions developed by the

CMRAE Laboratory at MIT by Prof. H. Lechtman)

1) Prepare the necessary materials:

a. Film packets (Dr. Reber’s office)

b. Print-coating brushes (with film)

c. Polaroid 545 Land Film Holder (Dr. Reber’s office)

d. One plastic tray filled with sodium sulfite solution (under the sink in the darkroom)

e. One plastic tray filled with hypo flo wetting agent (under the sink in the darkroom)

f. One plastic tray for washing in running water (next to sink in the darkroom)

g. Clips for drying

All of these materials are available in the archaeology labs. Dr. Reber will prepare all chemical solutions used in processing the negatives, and each student will be trained in proper handling procedures.

2) Make sure the cloth cover on the base of the camera is clean and dust-free. Place the object to be photographed on top of the cloth underneath the camera.

3) Brush off the lens with the air-brush found next to the camera.

4) Compose the photograph. The reflex viewer head should be in position on top of the camera body above the ground glass screen. If it is not, clip it into place by engaging the small metal pins on either side of the viewer head in the spring clips on either side of the ground glass screen. Open the lens aperture completely to f-4. Turn the shutter speed to B, and screw the trigger into the closed position. This allows you to see things in the top of the camera. Turn on the flood lights. Unlock the camera by loosening the camera lock handle located on the right side of the camera against the post behind the camera body. Looking through the reflex viewer head, focus on the object by moving the entire camera up or down with the large black knob on the left side of the post behind the camera body. Adjust the magnification with the large black bellows knob on the right lower side of the camera body so that the object to be photographed fills the area bounded by the four corner marks on the ground glass screen. Refocus the object and lock the camera in position. The solid black boundary line on the ground glass screen indicates the absolute boundary of the film. It is recommended that you keep your object well inside this line. Place an appropriate scale in the picture parallel to one edge of the film. Do not place the scale very close to the object ot be photographed; it is acceptable for part of the scale to extend beyond the area bounded by the corner marks on the ground glass screen, but the object must not. When photographing objects with a large amount of depth, the scale must be placed at the principle plane of focus and not at the top or bottom of the object, as the scale will only indicate the actual magnification of the photograph if it is at this position. This can be accomplished by propping the scale up to the level of the principle plane of focus. BE SURE TO TURN THE FLOOD LIGHTS OFF WHEN YOU ARE NOT USING THEM. The lamps become very hot. Determine the appropriate lens aperture setting. The diaphragms in the lenses for the MP-4 camera are used to control the focal depth of field of the photographic image. The diaphragms are controlled with the f:stop on the lens body. The ring has a scale on it which is graduated in f:stop numbers from 4 to 32; the larger the f:stop number, the smaller the diaphragm opening and the greater the depth of field.

When photographing relatively flat objects, the depth of field is not a problem and the lens diaphragm can be set at any setting. It is recommended that the lens diaphragm be set at f:8 or f:11 in these cases as it is at this setting that the lens gives the best resolution.

On the other hand, if the object to be photographed is quite tall, the depth of field will have to be increased by closing the lens diaphragm further. One way to test if the depth of field is adequate is to focus on a point halfway between the top and bottom of the area of the object that will appear in the photograph with the lens diaphragm wide open to f:4. Place one scale on top of the object and another at the lowest point on the object that will appear in the photograph. Turn the flood lights on and, while looking through the reflex viewer head, close the lens diaphragm until both scales come into focus.

With each full f:stop setting that the lens is closed, the diaphragm opening is reduced by an amount that results in the amount of light that passes through the lens being cut in half. As the lens is stopped down, the image on the ground glass screen quickly becomes dark. The black and white scales are easier to see in dim light than the object and it is, therefore, easier to see when they come into focus. Turning off the ceiling lights will make it easier to see very dim images.

When you are unsure about the setting, it is always best to choose the smaller lens aperture. AS ALWAYS, KEEP THE FLOOD LAMPS OFF WHEN NOT IN USE.

5) Determine the proper exposure. Once the appropriate lens aperture setting has been determined, set the lens diaphragm to this setting. Remove the reflex viewer head by depressing one of the spring tabs on either side of the ground glass screen and carefully lifting the viewer head off of the camera body. Set the viewer head aside in a safe place. Place the grayscale card, found next to the camera, at or near the plane of focus, parallel to the bench top. In the case of a delicate set-up, the card can be held just above the object to be photographed while the reading of light intensity is taken. It is also possible to read the light intensity before you compose the photograph with the gray card flat on the light box provided that you do not change the position of the lights or the bellows before taking the picture.

Get the light meter, make sure all photo lamps are on, and all room lights are off. Place the light meter on top of the ground glass shield, and push the trigger on the side of the light meter up. If the black line is at 12, repeat the process, but when pushing the trigger down. Do this twice, and take the approximate average of the numbers that the black line is pointing at. Move the dial on the light meter until the average number from the light reading is pointed to by the green line in the central window. Now, look at the top of the dial and match the f-stop you’re using to the number directly above it. That number is the exposure speed.

6) Load the film onto the film holder. Before being mounted on the camera, a film packet must be loaded onto the Polaroid 545 Land Film Holder, which is located next to the film in Dr. Reber’s office. The film holder can hold only one film exposure at a time—one film packet. To load a film packet:

a. Move the control arm to “L.” (the arm is left at “P” while the holder is not in use.)

b. Orient the packet with the metal cap end to the left and the flaps on the right so that the word “Polaroid” is right-side-up and facing you. Be very careful not to touch the negative pod area, which is clearly marked with warning symbols. With one or both hands (if extra leverage is desired) hold the packet about the middle area (left of the pod) and insert it into the film holder. Once it is inserted about halfway, hold the flap end of the packet and push it in until it stops. Make sure the packet is in as far as it will go, but also be careful not to buckle the packet.

7) Unscrew the trigger on the MP-3, and move the shutter speed from B to match that determined on the light meter. Exposure times longer than 1 second, marked on the Nikon by ‘’ after them (2’’ means 2 seconds, rather than ½ seconds) can be obtained by leaving the shutter speed set to B and timing yourself with a stopwatch. The shutter will open when the shutter release cable is pressed and close when it is released. NOTE: ALWAYS BE POSITIVE THAT THE SHUTTER IS CLOSED BEFORE LOADING THE CAMERA WITH FILM. OTHERWISE THE FILM WILL BE EXPOSED AND WASTED.

8) Insert the film holder into the MP-3 ground glass screen frame. The film holder is placed onto the MP-3 in the same way we demonstrated in lab the other week. Lift the right side of the ground glass screen frame and slide the film holder in place underneath it. Push the film holder as far as it will go and check to see that the arm in the left rear of the ground glass screen is displaced, extending to the left of the ground glass.

9) Expose the negative. Before exposing the negative, make certain that the interlock disabling switch (on the shutter trigger) is off. You may check this by testing the shutter release before exposing the negative. To reveal the negative, withdraw the packet by holding the flap firmly and pulling it until it stops. Check to see that the pod area is flat and smooth by running your thumb and forefinger lightly over it. If it is not, you have withdrawn the negative along with the envelope. Push the envelope in again, and withdraw it once more, checking the pod.

10) Take the picture. As soon as the picture is taken, push the envelope back into the ground glass frame and remove the film holder altogether. Forgetting to replace the envelope will result in a ruined negative. Move the control arm to “P” (process). From the flap end, pull out the film packet with a firm, unhesitating motion.

11) Time the print development. As with other Polaroid films, the positive print develops immediately and its development must be timed. As soon as the packet is removed from the film holder, begin timing the processing. The temperature of the film holder at the time of processing exerts an important influence on the processing time required. At room temperature (70 degrees F) or greater, the processing time is 20 seconds. Please consult Dr. Reber in cases of lower film/film holder temperature, as the processing time must be adjusted accordingly. After the recommended processing time (probably 20 seconds) separate the print from the negative by grasping the two flaps opposite the cap end and quickly pulling the packet apart all the way to the cap end.

12) Pull the print away from the envelope backing. The print and its mask will separate completely from the negative section and cap. Remove the mask from the print and discard.

13) Coat the print. Place the print on a clean surface (use craft or plain white paper) and coat it immediately, using the coating roller provided with the film. Six to eight overlapping strokes are recommended to cover the entire print, including the borders. Each coater will cover no more than five prints; do not attempt to stretch the use life of a coater, because the results are streaky and poor. Allow the print to air dry for several minutes before handling. The coat tube MUST be capped between uses.

14) Separate the negative from the envelope and the cap. Never touch the damp face of the negative. Flex the perforation at the metal cap end of the negative. Holding the cap in the right hand and the tab in the left, tear the negative along the perforation. Do this with extreme care!! If your tear does not remain on the perforation, the negative will be torn and thus ruined!! The opposite tab remains in place.

15) Clear the negative in sodium sulfite solution. Go immediately to the sodium sulfite solution tray. Insert the negative GENTLY into the tray, using a pair of tongs held at the EDGE of the negative. If you hold the negative in the middle with the tongs, you will scratch the negative! Gently agitate the tray by moving the tray up and down for about one minute as the dye clears and the developer drops off (a layer of dark purple/black developer still adhering to the negative normally sloughs off during immersion in sodium sulfite). Sodium sulfite clears the negative so that it will not be stained or marked by the residual chemical activity of the developer. Note: solution should be at room temperature, 65-75 F.

16) Wash the negative in running water at about 70 F for about five minutes. Remove the remaining tab from the negative, flexing along the perforation and tearing carefully away.

17) Dip the negative in wetting agent. After washing, dip the negative briefly in Kodak Photo-Flo wetting agent, and drain for a few seconds.

18) Dry the negative. Hang the negative to dry by clipping it to the wire hanging above your head. Be sure to clip the negative at the EDGE rather than in the middle of the negative.

19) When you are finished photographing, clean the photo area as well as possible. Turn out the flood lights. Replace the jury-rigged lens cap on the MP-3 lens. Shake out the cloth that you used for a background to remove any dust you have inadvertently left in the process of photographing. Remove all personal items from the bench.

20) Store the negative. Once a negative is dry, place it in a protective wallet. These are kept in the top drawer of the desk with the MP-3 camera on top of it. Record information concerning the object and the photographic conditions on the envelope before inserting the negative. Include with your information

a. What the object is, including site name and number, FS or lot number, square and level/feature information.

b. The f:stop and shutter speed

c. Camera position when the picture was taken

d. Whether there are other photographs of this object

This information ensures that the photograph can be retaken in case of disaster, and that we are not awash with photos of unidentified objects after this class is over.