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Taking the Fear
Factor out of Digital Photography of Paintings
By Jay Gross
Artists frequently need images of their paintings for juried art
shows and galleries, and slides are becoming out dated in favor of
digital images. There’s only one trick to this, and it’s light. Whether
you shoot digital or film, the lighting starts the same: two broad
sources at 45-degree angles, aligned with the vertical midpoint of the
painting and equally
spaced.
For small works, a copy stand does this job admirably. To shoot
paintings, hang them on a wall and set up the lights and camera
carefully. You can shoot these on the floor, but it’s difficult to
position the camera at the center of the pieces.
One setup does all. See the accompanying diagrams. The goal is even
light across the entire width and height of the original. For very large
pieces you might need four lights - two on each side - but usually you
can just move the lights farther from the subject to achieve even
distribution. Digital photography is much more forgiving than film of
light color and low light quantity, but you still need “enough” light,
and the color of both lights must match.
Color matters
For predictable results use “hot” lights, and forget electronic flash,
especially the one built into your digital camera. You can make do with
“shop” lights that have aluminum reflectors and a grab-handle to attach
them to solid surfaces. With some applied ingenuity, these can be
clipped to chairs, floor lamps, or other objects if you don’t have
actual light stands.
Bare bulbs are acceptable., Reflector or not, however the bulbs must be
the same wattage and the same output. Digital cameras are fairly
forgiving of color temperature as long as it’s not a mixture. You can
use household bulbs, but get the same brand and wattage, bought at the
same time, and new, never used in a lamp.
Far better choices are “halogen” - quartz-halide - bulbs, or photofloods
from a camera store. Both are much more predictable for color balance.
Halogen bulbs work best, by far. For critical work, take extreme care
with the color balance of your lights and eliminate all light falling on
the subject that doesn’t come from the lamps you choose. Shoot at night
to avoid daylight from windows, and turn off all other lights in the
shooting area, especially fluorescents. Even a tiny bit of fluorescent
will skew the color something awful.
With digital photography, you can get away with a world of sins if you
don’t mind doing some editing in Photoshop or other program after the
shoot. To avoid editing, control the lights carefully.
When shooting film, you have to match the color of the light to the
sensitivity of the film, or the results will be predictably bad. For
photofloods, halogens, and the like, use “Type B” film. The “type”
simply means the film is color balanced to the normal color output of
halogen light sources (3200˚ K).
Digital cameras adjust color with “white balance,” many of them
automatically, some of them whether you want it done or not. Turn
automation on and see what happens, and if the results aren’t to your
liking, go manual. You might have to consult the camera’s manual to find
its manual mode.
Control the surroundings
To keep down stray reflections and color problems, cover up large
surfaces that aren’t neutral - gray or black. This especially applies to
other lights like lamps and (gack!) fluorescents. If you normally wear
hot pink sweaters, and golf green pants, go Ninja during the shoot. This
applies double if the painting contains large areas of black or very
dark color, and is under glass or plastic. Color bias often rears its
ugly head in the shadows of the resulting image.
Control reflections
Many watermedia paintings live in frames under glass or Plexiglas, and
you’ll have to control reflections. If you set up the lights correctly
according to the diagram, you won’t have reflections off the glass or
Plex. Even so, large subjects are more difficult to manage for
reflections, and the worst is curved surfaces - for example, Plex that’s
bowed, even slightly.
Sometimes, you actually need some reflection. A good example is a work
containing important texture. To render the texture in the picture,
reduce the angle of the lighting relative to the art. So, 30 degrees
instead of 45, even less if need be. The trade-off is the even
distribution of light, so this technique is difficult on large objects,
for which you might have to add light sources and strike a delicate
balance between showing the texture and balancing the lighting and the
exposure.
Perspective
There’s only one correct perspective for paintings: straight-on, square
to all edges of the film plane (LCD-plane, as the case may be). This is
simply achieved by putting the camera on a tripod and positioning it in
the center of the original, top to bottom, left to right, and then
moving it back as far as necessary to take the picture. Use the3 LCD
preview to achieve the parallelity you seek. Patience!
With simple lenses, like those on inexpensive digital cameras, you’ll
get better results zoomed out a little. You’d probably never notice the
lenses’ distortion with normal pictures, but it shows up as bowed edges
when you photograph an object that doesn’t have bowed edges. Higher end
cameras offer specialized (expensive!) lenses for such photography.
To make life easier, it’s best if the original lies flat against the
wall. This is rarely true of paintings that hang from wires on their
backs, so prop them up from the bottom to make them parallel to the
wall, or adjust the camera’s position.
Exposure
A well exposed picture of your painting should look, well, like the
original. To achieve this ideal (yeah, right), get scientific. Put a
Kodak Gray Card at the edge of the picture, and when the resulting image
shows the same tone as the original card (keep one by the computer for
just such judgements), the exposure is (quote) ideal (unquote). You can
get Gray Cards at camera stores, or simply paint your own target in
neutral grays with saturated swatches from your palette.
Tips for success
• Don’t judge the image by the display on the LCD. Look at it on a
computer monitor. Big.
• A little underexposure is better than obliterating highlight detail,
but if you’re going to print these out, also watch out for blocking up
the shadows with too much under-exposure.
• Stick a color target/grayscale (see illustration) on the original, so
you’ll have something to check color and exposure with later. Even if
you retain the original painting to compare with, the targets will help
quantify how known colors reproduce on a monitor.
• If it looks squonked (technical term) on the LCD, fix the perspective
before going ahead. It’s far better to fix it here than in image editing
software.
Unlike playing trombone, practice won’t make perfect, because perfect
isn’t possible. Remember you’re converting from one medium to another,
large to small, tangible to electronic. Something often has to give.
There are subjects - reflective paints, UV (i.e., Dayglo) pigments,
foils and the like - that are impossible to represent without
substantial hand work.
Getting the image on a CD
First, you have to get the file into your computer. Most digital cameras
offer a USB or Firewire connection for this purpose. Install the
software first, particularly for USB connections. Then hook up the wire
and turn the camera on. With Windows XP, the process should be seamless
from there. Drag the files to your harddisk (C drive or other if you
have them).
You could instead pop the memory chip out of the camera, insert it in
the computer, and drag the files from the chip’s window to the computer
drive’s window. This method is simpler, and probably requires less
software learning.
Perform whatever editing you need. Most digital cameras shoot with a
bluish or cyanish color cast. Take care matching the color on your
monitor to the color of the original. Judge the values you see in the
color target, then evaluate the image.
Make the CD from the (edited or not) picture on the computer drive, not
from the camera or its memory chip. This gives the CD writing process a
better chance to go smoothly. Computers differ greatly on the process of
making CD’s, so don’t be surprised if this doesn’t quite apply to yours.
Load your CD writing software, drag the files to the CD, and hit “burn.”
On Macs, drop the file onto the CD drive’s icon. The computer will ask
if you want to write the CD now. You do.
Resolution
SCWS requires a resolution of at least 1024x768, or about 1 megapixel.
Use more, lots more, if you can, but don’t use less. Set your camera to
its maximum resolution and go. Don’t worry about file size. With a
requirement of one image per disk, there’s no practical limit.
The juror will open your image on his computer and look at your work on
his monitor. His final decisions, however, will be made from the actual
original painting. Whew!
Pitfalls
Watch out for:
• Ghosts - pictures of yourself operating the camera. You’ll find these
in deep shadow areas behind glass or Plex. The solution is to set the
camera’s self timer and step away while the picture exposes. If you have
this problem, also be sure to black out any bright objects behind the
camera.
• Missing textures. It’s often difficult or impossible to depict texture
in an image of a painting, mostly because the size of the final image is
much smaller than the original. You can use “sharpen” in the editing
process to emphasize texture, but it won’t be accurate to the original.
• Foil and reflective materials. This is worse case scenario for digital
(or film) photos of paintings. Gold flecks, silver foils, and everything
similar will render either black and blitzed out, and gold will rarely
have the correct gold color. The only solution is hand work on the
digital image.
• UV-reflective paints. There are many of these, including the notorious
“Day-Glow”. These may pick up nonsensical color or render black, or they
might just look dull and lifeless, unlike how they appear on the canvas
or paper. These, too, require hand work to correct. It’s not something
you did wrong - these specialty paints are designed to reflect
wavelengths of light that cameras, particularly film, don’t see.
References:
A good, free photo editing program: www.irfanview.com
Photo light stands and continuous lights:
www.myphotohome.com
(look for “continuous” lights with “quartz” lamps and stands. This is
where I got my units.
www.jerrysartarama.com
(look for “easel lamps” – these are overpriced, but a pair of them will
work.)
Slides (bah! Old tech!) from digital images:
www.powerproslides.com
(This is where I get the ones SCWS uses. Excellent quality,and they’re
only about $1.40 each.)
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