slide copy

FILM: The film used is Kodak's standard slide copy film which has much lower contrast than normal film provides an excellent copy medium. The light box provides a direct and quick means to provide colour balance adjustment.

COLOUR BALANCE: Having taken a number of shots of test images with grey and know colour, the correct setting for filters was determined. Since the film specifies a colour filter factor for the batch, a base setting for the light source can be determined by subtracting the Kodak numbers from my real settings: ( setting light box to 5M, 25Y, and the film package shows 5M, 15Y, the basic setting for my light box is 10Y greater than the film numbers).

EXPOSURE: Kodak indicates an film speed on my box of film to be 40, however I find my 1n reads best at iso 64 for the target exposures. For this film, at f11, 1:1 scale, shutter speed is about 1/10 second. Mirror lockup is used. Since this film has about 1/2 the contrast as normal slide film, a two stop change in exposure is required to make the same change that 1 stop on the original film.

ALTERNATIVE LIGHT SOURCES: While the IEE box is great, and comes with a standard copy stand mast, a used dichroic light source form an enlarger can be used. Given the large number of used ones I see at photo flee markets, that should be an good choice. An alternative would be either a slide projector or other Quartz light source (desk lamp??) plus a set of colour printing filters (CP series)

WHY USE THIS TYPE OF APPROACH : The primary reason is quality of copy. First off the film is balanced for tungsten, and using normal slide film is out of the question due to the contrast becoming excessive in the copies. So filtering and low temperature light is needed. The Dichroic light box makes setting the filtration easy and there is no fading.

Since I am using a high quality macro lens, the image quality is extremely good, These lens are much sharper than the simple lens in a "slide copy tube" which look like a lens tube with a holder at the end, and have fixed focus. I have one of those tubes, and the lens quality is poor. For the Canon L series macro, the copied image is grain level sharp at f5.6 to f11. The Tamron lens is best at f11. Since I use an extension tube, the macro goes to greater than 1:1 magnification, so cropping can be done. Also, the since the light meter is working normally, the exposure can be read by the meter, however usually a fixed exposure is used for any given magnification factor. And one or two stops are needed to alter an original that is either too light or dark