Photodocumentation Procedu res

4. Photodocumentation Procedu res

1 ) Determ ine exposure

For u ltraviolet fl uorescence, it is possi ble to approximate the exposure from a light meter read ing with a handheld light meter (see step 2 if a meter is not avai lable) . The meter m ust be capable of calcu lati ng long exposures. The meter is used to measure the reflected light com i n g from the plate. First, turn on both UV lamps (in the shortwave mode) . Look through the camera to see that the TLC plate is centered in the viewer. C heck to see that the UV box is not blocking any part of the i mage . Move the copy stand arm , and back the camera away from the opening of the box. Set the handheld light

Photodocumentation of the TLC Plate Using Ultraviolet Light

normally reach the fi l m , the exposure m ust be adj usted . Following is a list of the filter factors for each of the filters used :

Fi lter Exposure i ncrease in f-stops 2E N /A

The amount of correction needed i s the sum of the exposure increase for the filters that are used . For exam ple, for a color slide, all four filters are used ,

so the exposure i s increased by one f-stop .

2) Photograph a n d bracket shots Make sure that the camera ASA is set to 800 and the f- stop is set to

f 8.0. Photograph the plate with the exposure time set to the mete red read i ng. Remember that the gel filters affect the ex posu re by loweri ng the amount of light reaching the film. The fi l m will be underexposed at the metered read ing, but it is a good starti ng point. For exam ple, if the metered exposure ind icates an exposure time of 4 seconds, then exposu res of 4, 8 , and 1 6 seconds are l i kely t o prod uce a t least o n e negative that is properly exposed . If a light meter is not available, start with an exposure of 1 second and double the exposure time with each s hot to 32 seconds. For exam ple,

take a photograph with the exposu re time set to 1 second. Then set the camera exposu re to the bulb position and take photographs at 2 , 4 , 8 , 1 6, and 3 2 seconds. Ti ming can be done with a darkroom clock or by si m ply

counting the ti me.

3 ) Document and log each shot

I t is advisable to keep a written document of the photographs. This i nfor­ mation can be kept in a laboratory notebook, in a ring binder, or on a computer database. The i nfo rmation is valuable i n that it provides documen­

tation on the appropriate exposure for the photograph . I f the photographs do not come out satisfacto ri ly, the i nformation can be useful in making

exposure corrections. I t also allows for tracking of photographs, particularly for multiple origi nals that may be s i m i lar. Most i m portant, should the photo­ graph need to be duplicated at a later date, all necessary i nformation on the exposure has been retai ned. A sample log s heet i s attached (Attachment B).

4) Rewind film and send for development After all exposures are m ade, rewind and remove the film from the camera. Send the film to a reliable photo processing laboratory. I nd icate to the lab

that the film has been exposed at 800 ASA and should be " push- processed . " Also ask the lab to n u m ber the slides, a s this helps correlate each shot with written documentatio n . B lack-and-wh ite film is processed and pri nted as a

proof sheet. I ndivid ual photographs can be chosen for printing from the proof s heet or the slide.

5) Label and store slides and pri nts Labeling of slides is strongly encou raged. This is particu larly useful when slides are borrowed by col leagues for presentations, so that the slides can be

easily refiled . Proof sheets should be placed in 8 x 1 0" polyethylene sheet

Striegel . Hill

Slide labels can be handwritte n , typed, or generated by computer. The label should contain at least: Name, Date, and Subiect. Other useful

i nformation can be added to the label , as wel l . A sample label may look l i ke th is:

Date

RoU No.

Photo No.

Subject Camera

Lens

f-stop

Shutter speed

Film

Photographer

P RO Laser labels are designed to fit slide m ou nts and can be printed on laser pri nters . They can be o btained through photographic suppl iers o r ordered

d i rectly from the man ufacturer. For d i rect orders, write to: Slide Scribe, 752 Washi ngton Avenue So. , M i n neapol is, M N 5543 9 .

Helpful Hint: A dot can b e placed i n the upper right corner of each label and used to orient slides for proiection. First, the slide is held with the image upside down. Next, the label is attached to the front face of the slide, on the top border. The dot can be used to determine the proper orientation of the

slide. When all slides are properly placed in the slide carousel, the dot will

be seen on the outer edge of the slide.

Always use polyethylene holders for photographic images, as nonarchival m aterials will damage the i mage. For valuable slides, make d u pl icates and store one copy in a separate place.

Attachment A

Instructions for the Manufacture of an Inexpensive UV Box

Cardboard boxes can be u sed to make an inexpensive chamber for u ltraviolet fluorescence photography. First, the top flaps of the box are removed with a util ity k n ife . Then, two right triangles are cut from one side of the box.