Harold implanted the idea of X-rays with onions in me. Although more than covered with professional requirements, I tried my hand at vegetable x-ray photography.
I can say it’s fun. Although a defective screen had to be replaced at the beginning. And you need some patience. Not every shot shows its beauty from the beginning. Some have to be developed first.
Let’s start with a corncob. It has many outer leaf layers, which lie close to it. X-rays look through and show the layers at the edge of the bulb as fine lines.
Here is a comparison of X-ray on the left side versus Mammography on the right side. A Belgian endive and a lettuce show much more contrast and fine structure in a mammography whereas X-ray gives more the impression of softness. Which goes well for a salad.
Onions have a lot of liquid and are therefore radiopaque. I was curious to see which method would make it better to reveal the layerstructure of the onions. To my surprise mammography did a pretty good job.
Conventional X-ray offers more mystery, especially when you stack onions.
Some kind of layered structure also has fennel. I got two specimen that looked like mittens.
This year we had so many apples in our garden. They are red and look juicy. I had the chance to take two of them to my X-ray machine. With the help of two different orientations an interesting picture succeeds, because on of the apples still has a small branch.
May be there is some truth in the saying: an apple a day keeps the doctor away. But as the dentist would say: no teeth, no apple.
Karl Blossfeldt was a German photographer who lived from 1865 to 1932. He didn’t think himself a photographer. With his studies of plant forms he made an enormous contribution to plant photography. Here is a nice wikipedia article about him.
He started to do photograms. Plants or parts of plants were placed directly on film or paper suitable for exposure. Exposure then takes place without any optics. Later he built himself a wooden camera, which reminds me of Andreas Feininger.
Black and white backlit macro images with a background can be similar to Blossfeldt’s images.
Imagine a Nautilus shell tilted to the surface of the X-ray sensor. The parts close to the sensor are sharp, the distant parts unsharp. Because the X-ray beam creates a central projection. The focal plane is the plane of the sensor, in focus are those parts close to the sensor.
The shell looks like entering the image or leaving it.
How to show the sun in the middle of a sunflower ? For astronomers it is quite common to look at the sun in hydrogen alpha light, which is a pure red at 635nm. With artistic eyes, a red center might be overdone.
So I tried two different representations, one in BW that is close to the natural look and feel of a sunflower and one with a light blue in the center as complementary color to the yellow petals.
The surface structure of our sun can be seen like astronomers see it.
There is no photo of the next digital X-ray image of a sunflower with its stalk and a leaf:
Our weather is more and more weird. Today was the second day with a warm sun and a blue sky. Nights are getting pretty cold, days up to 25 degrees Celsius.
Cleaning up our garden led us to some old physalis which were a little more than a skeleton. In autumn these fruits look like lanterns, now they resemble an X-ray.
I did this shot on a lightbox using manual HDR technique.In Lab color mode I obtained this image with a pur black background.
It’s an exoskeleton for the fruit inside which remains that way without bruises.
How to communicate an erratic process in terms of an image ? The Iliadic greek were pirates of the Mediterranean with fast vessels, invading mainland from the seas, enslaving people, robbing stocks and much more.
The writing down of the Ilias was between 678 and 662 B.C., a time of Assyrian dominance and cultural superiority.
With three different Nautilus shells I bought last September on Crete I did this composition on my big X-ray sensor with 35cm x 43 cm and 170µm per pixel resolution. Two energy levels were necessary to get a high resolution image of the core of the Nautilus shells.
To overcome the look-and-feel of a medical X-ray it is a logical idea to invert the light. Black becomes white and vice versa. White means shining through of X-rays, black means opacity. It’s like a dream !
How to prepare a X-ray session ? What flowers suit to a Nautilus shell ? Where does color come in ?
I went to my gorgeous florist to have a look what offer she can make during wintertime. My phantasy were spinning around something ethereal or unrealistic. I bought some flowers with respect to their shape.
The Anthuria caught my eye immediately. The Tulip was still closed and got more and more yellow within hours.
All these compositions shown here were made with dual energy X-ray. The lowest energy of the tube is 40kV, which yields with 4 mAs a quite good insight of flowers. For the center of the Nautilus shell, 70kV and 2.5 mAs is more appropriate.
My first composition was a Nautilus taking off a bouquet of flowers. This reminded me of Renaissance engravings full of symbols. I do not feel depressed. The representation as a X-ray positive jsut shows the bouquet.
A more grounded composition is the second with a Nautilus shell moving towards the roots of my bouquet. Hopefully, the plants will survive. The positive representation always needs some extra editing. By just inverting the Blacks and the Whites the Nautilus would be too dark. Our reception cannot be just inverted and feels alright.
With the look-and-feel of old engravings in mind the third composition ist between surreal and a still. It took me some time to mask out the flaws of an original X-ray to get a true black background. Masking can be done iteratively and easily combined with Photoshop. („That’s what Photoshop is made for !“).
Some colorizing was done to overcome missing photographic shots. There was simply no time in my X-ray unit to do both at a time.
My fourth composition is called „The Argonauts“. The Nautilus shell serves as Argo, the legendary fast ship, with its crew, called Argonauts. The colored version is more convenient for our eyes. As before the X-ray positive looks more ethereal.
Is there poetry in a landscape ? Does an image give the impression of poetry ? These questions came up when looking down from the Zugspitze at the Alpine folding.
It was a cold day with with warm rays from the sun. No winds, except at the border to Austria. We were lucky to spend a few hours up there at about 2960m.
This folding was soft and wild at the same time. Is it a solidified sea ? A petrified curtain ? Only the light creates the feelings.
X-rays were initially used for research in atomic physics and medical diagnostics and therapy. Their ability to reveal structures inside an object even with an opaque surface was the driving feature of scientific and technical development of X-rays. Nowadays, beside its proven medical usefulness, X-rays are used to examine technical structures and there are telescopes to map X-rays from our Galaxy and the universe. Every radiological technician who starts in its profession learns to do X-rays of common structures like flowers, animals or teddy bears.
In the digital era, X-ray images are obtained using sensors, while film was used historically. The sensors in the medical radiological field have dimensions such as 24cm x 30cm or 43cm x 43cm. The corresponding spatial resolution for these sensors is between 70µm and 140µm. A typical high-end camera used by a professional or advanced amateur photographer might have a pixel resolution between 4 and 8 µm. Therefore, photographers might well wonder if there is any precise imaging possible with such pixel size. Let’s look at this a little more closely.
X-rays, like visible light, can be characterized by their energy or wavelength. Shorter wavelengths correspond to higher energy. The capability to penetrate an opaque structure increases with energy. If you think of a photon as a particle, smaller particles with higher energies penetrate an object more easily. An overview of this relationship is given in the table shown here:
To make this more clear, here is a series of X-Ray images with increasing energy. The first image was obtained with 40 kV which corresponds to a wavelength of 0.031nm. Our eyes are only able to see wavelengths between 400nm (blue) and 750 nm (red). Therefore, photons with a wavelength at 40 kV cannot be seen with the naked eye. The peripheral parts of the Nautilus shell are clearly depicted. A photographer would classify the circle at the center of the shell as „blown out“. In fact, they are not blown out. The radiation is not able to resolve the structure, because the wavelength of the X-rays is too long in this case to penetrate the shell.
Let’s go to shorter wavelengths (implying higher energies). Using 50 kV or a wavelength of 0.024nm gives more structure to the central parts. The photographic impression of a „blown out“ center is reduced. However, looking at the peripheral parts of the Nautilus there is a loss of intensity and a more grayish impression. It is conceivable that this might be regarded as an overall acceptable but subtle effect.
To take this further, we can go up to 60 kV or down to 0.0207nm. The center is now close to perfectly „exposed“ with some detail apparent, although some smaller structures are still not resolved. The intensity loss at the peripheral parts increases and is now pronounced. A photographer would clearly regard the periphery as „underexposed“.
The last example of this direction of higher energy and shorter wavelengths is 70 kV or a wavelength of 0.0177nm. The photons wavelength is now 57% compared to 40 kV. You may think of this as „smaller“ photons. The result is a clearly depicted core with a complete loss of peripheral structure. A photographer would have every reason to be worried about „underexposure“ and loss of detail everywhere but the center.
What we’ve seen here is that the capability of X-rays to penetrate an object and to go through an object is dependent on energy levels. With shorter wavelengths X-rays go through an object without disturbance but our sensor is „blown out“ at the peripheral parts of the Nautilus shell. Using 70 kV the central parts are much better resolved, but the periphery is too dark. The energy to use for any X-ray image therefore often depends on the primary goal of which portion of the subject is most important to capture.
If combined, the four exposures shown provide a beautiful, nearly weightless image: