Rangefinder Magazine
September 2005

Click Here for printable version of this article.

At some point in your career as a photographer, you will probably need to make 35mm slides from flat copy, artwork or paintings. The reasons for this vary, such as for archiving, clients or promotional reasons. The equipment you need is relatively straightforward, but there are some important precautions to take before you start shooting.

The Bogen/Manfrotto Super Repro Copy Stand with extra large 30x36-inch baseboard

One of the most important considerations is your camera support. If it’s even the slightest bit unstable, you’ll wind up with blurred images. If you’re shooting artwork that can fit on a tabletop, a copy stand will likely be the best choice, but if the work is large, as in the form of paintings, you’ll need to use a tripod and free-standing lights to photograph your work.

Depending on the copy stand you purchase, it will come with two, four or no lights at all. The latter may be preferable if you already have your own lights. With the stand above, you would attach the camera to the mount, which you then crank up and down as necessary to frame your images. When using this type of stand, it’s important to make sure your camera is perpendicular to your artwork. If it isn’t, “keystoning” will be evident (where one part of the image is visibly wider than the other). You can scan the image into a computer and fix it with software, but eliminating it at the source will save much wasted time later.

In the event that you’ll be copying artwork on the wall, it’s important to position the camera exactly parallel to your work. Use a level and measure the position of the camera so it faces the exact center of your artwork, both vertically and horizontally. If necessary, apply weights to the tripod legs to make sure they don’t move. Another option is to attach an extension arm to the tripod head. Again, make sure the tripod and the base are secure.

	An example of a commercially available copy stand—the Bogen/Manfrotto System 800 Repro Copy Stand with motorized carriage and support arm

About Lighting
Lighting for your artwork needs to be reliable and accurate. If you’re planning to invest in lights, you can purchase photographic quality tungsten lights with barn doors to help direct and shape the light. These lights are an excellent choice as the bulbs are long lasting, and they maintain their color temperature quite well over the life of the bulb. Another, less expensive option is to use construction-grade tungsten lights. The only down side is that they don’t come with barn doors to shape the light. If you intend to use flash, you will need to bounce it using reflectors. Direct use of flash without any filtration or softening will cause hotspots on your work.

Note: Do not use photoflood lights. They are expensive and their color quality degrades rapidly.

Depending on the copy stand you buy, lights are sometimes included. To set up the lights properly, make sure they are angled at approximately 45 degrees to the surface. If your copy stand does not come with lights, you will need to determine the maximum size of the work you’ll be shooting and set the lights to be an equal distance away from the camera and parallel to it.

When photographing work on the wall, position the lights so they are slightly higher than the center of the artwork. Square artwork to the camera as much as possible, and set the lights to be parallel to the camera.

When positioning the lights, use an incident meter to determine the evenness of lighting from edge to edge and in the center of your shooting area. The reading should be evenly accurate on all corners and in the center. Once you’ve determined the correct location, you can place masking tape on the floor marking the position of the camera and light stands. This will speed the setup process the next time.

Keep backgrounds as neutral as possible with no extra colors. Shooting flat copy/artwork against black velveteen is recommended because it creates a black matte around the artwork, eliminating the need for masking later. Be aware that the velveteen surface has to be clean. Bright pieces of lint, etc., will show up as pinholes on your film. Use Scotch tape wrapped around your fingers to clean the velveteen of lint.

	This Bogen Super Repro Copy Stand uses a translucent acrylic scrim in place over the lights. It also sports a raised platform, and the central rectangle on the copy surface is also translucent, permitting light to be directed upwards through the table for photographing backlit artwork.

For flat copy or artwork on the wall, a straight 50mm lens with a 35mm camera is a good choice for film, partly because is will give you an accurate “real life” representation. If you use a wider-angle lens you are likely to encounter some distortion at the edges, while a longer focal length lens will tend to compress the image.

Photograph all works vertically, not horizontally. Adjust the camera for a vertical format if necessary.
When using a digital camera, you’ll want to choose a focal length somewhere between the wide-angle and telephoto settings, which will be different for each camera. To see if there is any evidence of distortion, use graph paper while conducting your tests, which you can then view on your computer. Any distortion will be evident and you can adjust the focal length accordingly.

About Film
When shooting slides, use a professional quality tungsten-balanced film and keep it refrigerated prior to use. In the event that you’ll be shooting charcoal drawings, consider using black-and-white slide film as opposed to color, which will give you better results. In the event that you only have daylight film on hand, use an 80A filter.

Glare Issues
Glare is a problem that can ruin your images by creating hotspots on the surface. This can result from the artwork if it has a shiny surface or if the surface is uneven. One temptation is to tilt the lights to eliminate the glare, but that will disturb the uniform lighting on your surface. Here are some solutions to resolve glare issues:

This illustration is a top view of the arrangement for photographing artwork placed on a wall. Note that the lights are placed at an equal distance away from the camera and that the distance of the lights to the edges of the artwork are 2X the diagonal of the image. This illustration can also be used as a guide for setting up a copy stand (if you rotate the image 180 degrees).

Use a sheet of window glass to flatten the original. The window glass will introduce a tiny tint of green, depending on the glass, but usually it’s not enough to affect the image.

If you’re photographing a painting on the wall and the light is catching on speculars in the paint, you’ll have to use one or a combination of the following solutions:

• Create a shield that will fit over the camera lens, body and any surface that can cause reflections. A piece of black matte ABS plastic or black illustration board will do the trick. (In an extreme case, you would have to cover the white text on the camera lens to prevent the letters from reflecting back off the artwork.)

• If this is still not enough, you’ll need to get a set of polarizing filters to place in front of the lights. A separate stand or a clamp to hold the filter in place in front of the light is also necessary. Be careful not to place the filter too close to the light: The heat may melt it. The next step is to get a circular polarizing filter for your camera lens (B&W makes a good one). To make sure the filter is working properly, place a coin on the working surface directly in front of the lens; then slowly turn the ring on the filter. When the coin turns black, the light has been polarized. Mark the position of the polarizer on your camera lens using a silver or gold marker so you’ll remember how to set it properly. (Be aware that when shooting with a polarizer, you’ll lose around 2 stops.)

• Some photographers don’t like the effect created by polarizing filters, feeling that it creates an unacceptable light shift. If that’s the case, the next option is to use scrims, which are pieces of translucent material in a frame that creates a soft, diffuse glow (you can build an inexpensive frame from pieces of PVC pipe). You can use material such as frosted mylar, or you can buy different grades of material from Rosco (www.rosco.com). If you have a photography store that carries industrial supplies, they’ll likely have these materials.

• If the room has multiple reflections that you cannot block out, shoot your images at night.

About Dust and Lint
Some forms of dust and lint can be safely removed using an antistatic cloth (that you can purchase from a photography store), a carbon fiber brush (such as the ones sold to clean records) and hand-held, anti-static whisks. Other options are de-ionized filters that extract dust from the atmosphere. However, unless the original is in impeccable condition, you’re probably going to have to do some retouching after it’s photographed or scanned. If the image quality is critical, you’ll probably want to give the image a once-over in Photoshop or Paint Shop Pro.

Exposure & Vibration Issues
Make sure your tripod is of sturdy construction, and if necessary, brace the legs with sandbags. Also, make sure the tripod isn’t top heavy if you’re shooting artwork on the wall. It should be securely braced. If you have a copy stand, bolting the top of the stand to the wall is an effective solution.

Use a cable release to trip the shutter. If vibration is still a factor, use the mirror lockup (if your camera has one). Another option is to use the camera self-timer feature. By the time the shutter releases, the vibration should be gone.

Don’t use the in-camera meter unless you do the following: Use an 18-percent gray card to determine the correct exposure. Make sure the card completely fills the viewfinder when metering and use this setting to obtain the correct exposure. The 18-percent gray card will be accurate to within 2/10 stop.

Alternately, a handheld incident meter is a good solution, as is a narrow angle spot meter. The incident meter is also very useful for metering the corners and middle of the copy setup to make sure the lighting is even.

When exposing the film, depending on ISO, a setting of 1/8 at f/8 is a good starting point. Bracketing the shots in intervals of 1/3 to 1/2 stop is also recommended.

Flat Copy with a Digital Camera
When using a film or digital SLR, you should determine your aperture of maximum sharpness. [Note: Generally speaking, it is usually 11/2 to 2 stops stopped down from wide open, although this may vary from lens to lens. Lenses, even good ones, used wide open will sometimes suffer from certain aberrations like spherical aberration. The same is true at minimum apertures, where a lens may suffer a slight loss of sharpness due to refraction. These are not your optimally sharp apertures. A few tests of very high-resolution subject matter should provide the necessary data.]

On the issue of reciprocity, exposures of 1/8 to 1/2 second are not an issue. But when you get into long time exposures at high ISO settings such as ISO 800, you’ll get a lot of digital noise, and there’s not much you can do to correct it. There are, however, noise-reducing procedures, particularly if you shoot RAW image files processed in Photoshop CS2.

Use a white card and set a manual white balance. A good source is bright white paper stock sold in stationery stores. If your white balance doesn’t give you the exact color/exposure you’re after, you can adjust that in Photoshop.

Conclusion
Photographing artwork or flat copy need not be difficult. By following the above steps you will be able to produce highly accurate copies of your original artwork.  

Nathan Segal is a photographer/artist who specializes in combinations of digital photography and computer graphics. In recent years, he was part of a design team that contributed over 500 images to stock photography catalogs. Based in Victoria, B.C., he writes articles for various computer and photography magazines. He is also the associate editor for WebReference.com. You can email him with questions at: natsegal@islandhosting.com