19. March 2003
"Flatbed Photography"
Using a flatbed scanner as a camera to scan 3 dimensional objects! You've probably heard of it before but have you ever tried it?

Is it photography?
Well, using a flatbed scanner as a camera is of course very different from using a normal camera.
First of all you have to bring the subject to the "camera" and not the camera to the subject.
As a landscape photographer I'm used to taking my camera out to the place I'm going to photograph, but you can't do that with your flatbed scanner, so it becomes more like shooting in a studio.
But there are other limitations - your flatbed scanner will only scan on a limited area (perhaps about DIN A4) and the depth of field is quite narrow (to say the least). Your subject matter must be placed as close to the "camera" as possible and must be able to fit into the scanning area.
In other words: Place the subject matter directly onto the glass of the scanner and expect a depth of field of no more than perhaps one centimeter!
The subject must be able to lie still for a longer period (several seconds perhaps, so choose a "dead" subject matter).

But is it photography? Sure, why not! Take a look at the pictures in this gallery and I think you'll agree with me.

What to do?
You need a flatbed scanner. I believe almost anyone will do. Some are more sophisticated than others and some will provide you with higher resolutions than others.
My flatbed scanner is an Epson 1640SU which I used to scan my transparencies on. It's capable of almost 1600dpi, but for these scans I didn't use more than 800-1200dpi and less will also do!
I've chosen to scan fruits and vegetables here. They have the right size and there are lots of details - not at least because I've chosen old and dry fruit to add "character" to the pictures (a bit difficult to actually call them "photos").



The depth of field might vary from scanner to scanner. On some scanners you might also be able to set the focus. On my scanner absolute focus is just above the glass and things that are about 1,5 - 2 cm above the glass is out of focus.

Colors
Like any other scan you need to get correct colors. You can either create a profile for your scanner or simply rely on the scanner software to output in a certain color space.
For this task I choose the sRGB color space as output from my scanner resulting in pretty accurate colors.

A background
You need to choose a background also.
Obviously, because of the shallow depth of field, the background will mostly be out of focus, depending on the height of the 3D object.
When I started out, I wanted to make "high-key" pictures with an absolute white background. However, I soon realized that for this you would probably need a light box hanging over the scanner. I don't have a light box handy, so instead I chose to use a black background. Chose something that isn't shiny, like a piece of dark cloths for example.

Of course when the subject isn't too high, you can place a piece of paper or maybe even the lit of the scanner over the subject. The two following pictures illustrates the difference:


It's a matter of taste, but I do not like the shadows casted onto the paper placed directly above the chilies. The kind of images created with the black background was more what I was looking for. Should I ever get a light box I'll try to make some high-key pictures as well...

Depending a little bit upon the size of the subject I scanned at 800-1200 DPI. This results in very large pictures that can be printed out on 13x19 inch paper.

The results
OK, it's time to show the results of my efforts.
The amount of details you get is quite amazing. Often far better than with any other method, be it film or digital photography. Of course this again depends on the resolution at which you choose to scan, but should you have a flatbed scanner capable of 1600dpi - or perhaps even more - you'll see a lot of details!

Here's an example:



The picture above is an 8 by 8cm (3.15 x 3.15 inches) area scanned at 1200 DPI. At 300dpi this picture will be 32 by 32cm (12.6 x 12.6 inches) or, in other words, the width of a 13x19 inch paper. The red boxes are shown below in one to one pixel size:


(Both pictures have been sharpened somewhat).

Links
• Microscopy-uk.org Digital macroscopy in autumn with a flatbed scanner, by Dave Walker, UK


Gallery
Here are all the pictures of this "Flatbed Photography Gallery" - Enjoy!

See the other galleries