Grapes as an object of X-raying have been inspiring me for a long time. Their structure remind the doctor of the azini of a gland or lung. The phycisist likes very much the partial and complete overlays alternating with free positions. As an artist I get an unbelievable freedom of image design.
My first X-ray imaging attempts with grapes were carried aout in October 2017. I’d forgotten !
Can something succesful be repeated ? Can it be deepened ? What is the power of the composition ?
Two days ago I tried toput my creativity into the composition. Two pictures were taken from grapes which differ only slightly. Their X-ray view on our monitor had a clearly different effect.
My colleague by chance showed up with a bouquet of small sunflowers with long stalks. Amazing opportunity !
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.
A friend gave me a shell of a spider conch to make more fusion images. The scientific name of the spider conch is lambis lambis and it is a sea snail. There is a nice Wikipedia article on it.
The hard shell with a lot of radiopaque lime made me doubt the success of my X-rays. On top, my first attempt at a HighKey image wasn’t really convincing. Only the combination of a normal photography for the color, a HighKey image for a transparency effect together with the X-ray image resulted in nice image.
The X-ray image appear less lively, but full of formal power. The orientation of the animal is conveyed by the photographically reproduced color. There are only minimal hints wich orientation the X-ray has.
These are the corresponding X-ray images:
It feels like very long ago. Harold and I were taking the shots and X-rays of new compositions last week of April this year. Our first try was an orchid with two stems. The transparency effect is very much augmented using an X-ray. A stem behind petals doesn’t show easily in HDR light box photography.
With a Phase One camera at my disposal a strong crop of the composition shows the tenderness of our orchid much better. With a resolution still sufficient.
Since 1905 there is an X-ray meeting in Germany. It was the 100th time this year. Nowadays the convention takes place every year.
Besides the scientific news the convention offers the opportunity of caring for personal contacts. It is part of the beautiful things of the convention to meet old acquaintances and to exchange with them.
Leipzig fair is a great environment for this event. An agreeable tiredness affects me at the end of the day after many positive conversations. I left the celebration with relief.
Long lasting blossoms, turning up every year: my purple clematis in our garden.
It was my third X-ray session with flowers this week. Third fusion imaging attempt. After blue cornflower and blue aquilegia now a purple clematis. Big data on my hard disk.
Today we did it with mammography at 30 kV and 50 mAs. Lower noise ! Here is the positive representation of a single clematis:
I processed the lightbox HighKey series with a mask. There was a shift of 2 or 3 pixels from the lightest to the darker images. So I processed everything a second time to compensate for the shift. The HDR image shows a cut stalk. Photoshop is made for this.
The stalk can be lengthened like in the preceding X-ray. The fusion image shows hidden leaves, the core of the blossom and stalks much better:
The flower looks pretty fragile now, close to its natural appearance.
First flowers in spring show up. With much support from my colleagues I’m able to do some fusion images. We all would like to have another calendar.
Preparing the lightbox, the X-ray machines, my camera and picking out the data is a bunch of hassle.
My personal favorite is the blue cornflower. It looks like a print of an old botanic book:
The next day I turned my attention to our white and blue Aquilegias. No chance to process the raw data yesterday. Eventually, there was a chance today, after quite a bit of tedious work at my desk:
Fusion imaging is a method full of surprise. My red calla lilies revealed an effect I had forgotten completely. There must be a gradient in every X-ray exposure.
Preparing a fusion image composition with my 6 red calla lilies I found a troublesome gradient in the X-ray.
The cause for the gradient is a weakening of X-ray radiation at its origin in the X-ray tube. A closer look at the phenomenon can be found in my FAQ. This effect of variable recording of photons phycisists call „anode heel effect“.
As part of my creative process I rotated the composition shown above by 180 degrees and exposed it a second time with the same parameters. Note that post-production as well was done equally for both X-ray exposures !
It has been a long time since I thought about the basic properties of X-Ray tubes in graduate school. But I stumbled over an effect the other day that reminded me of one of these properties while using my new digital x-ray system. When I looked at this x-ray capture of six calla lilies, it was immediately clear that the system had operated in a way I had not entirely expected.
The background of the calla lily x-ray shows a gradient of deep black values at the top of the image ranging to intermediate gray values at the bottom. This was surprising.
At first I suspected a problem caused by the sensor. But after a little reflection, I realized this was not the case. It was not a bug, it was a feature !
Darker values in an X-ray film exhibit higher intensities of X-ray photons. Lower gray values mean lower intensities. Reading a bit more thoroughly about properties of X-rays and their production, the reason for the phenomenon became apparent to me. As the image of calla lilies shown above demonstrates, the distribution of X-rays emerging of a X-ray tube is not homogenous.
X-rays are produced by accelerating electrons towards the anode of an X-ray tube. The anode is made of metal in the shape of a plate. The applied electric voltage to the anode is positive and the negative charged electrons fly therefore straight into the anode. A magnification of this process is shown on the following plan:
The path of the electrons is about 6 – 8 cm long. About 1% of the braking energy in return is transformed into X-rays. 99% is heat production in the anode. The most common construction type of X-ray tubes in the medical diagnostic field is therefore constructed with a very rapid spinning anode to expel the heat.
The focal point on an anode is not a mathematical point. It is more like a circle (an even close model is an ellipse with a diameter of about 4 -5 mm). After electrons have entered the anode material and are slowed down, X-ray radiation leaves the edge of the plate. As the anode has an edge formed as an inclined plane, some X-ray photons can move freely, others have to pass a little more through the material of the anode. The longer the path of the photons through the anode is, the weaker the radiation’s intensity and the less is the sensor black. This effect of variable recording of photons by the anode plate is called „anode heel effect“. You can find more information on this topic in a Wikipedia article.
The described gradient on an X-ray exposure can be used creatively. Before looking at these creative possibilities, note that it is easy to use post-production tools such as Photoshop to compensate for the gradient. Medical diagnostic digital X-ray systems are already using something similar to compensate for the gradient.
Using the gradient that is generated creatively means taking control of the process. For example, by rotating the composition shown above by 180 degrees and exposing it a second time you get soft contrast in the calla lily blossoms and a “hard” contrast in the rendition of the stalks (see image below). For comparison, in the medical field an appropriate exposure would use the higher X-ray photon intensity at the bottom for structures that are more dense on one side only (for example, the heel of the foot). Note that acquisition (x-ray exposure) and post-production were done equally for both X-ray exposures !
Any rotational position can be thought of to integrate this effect in an image. The only limitation is the X-ray lighting area.