Hollandite as inclusion in quartz – a photographic challenge
Many papers have been written on macro photography and mineralogy. It certainly isn’t the purpose to revisit this. As photography and mineralogy are one of my personal interests, articles are published on a regular base. Quite often I’m been asked how I’ve made the image, which isn’t easy to reply as every image has its own approach. You put your own vision into an image; your own feelings, your own creation. Some call this art; I call it creativity.
A very good knowledge of software programs such as Photoshop, layering techniques and professional add-ins is, without doubt, essential when using digital photo equipment. It isn’t possible to tell you when or where to use a certain filter or photo technique. All depends on the image and, most of all, your inspiration. Without doubt, your photo must be sharp and of good quality before you make any attempts to improve the image with a software application. You can’t make a good image from a bad photo.
Knowledge of traditional photography is a sine qua non!
The image below is made up of two separate images. We see an inclusion of the quartz as a detail and an overview of that quartz crystal. Photographing the overview and detail needs a different approach as they have both specific difficulties.
The specimen has been collected at Anketsaketa (Ketsaketsa), Ambatofinandrahana District in the Amoroni’s Mania Region, Fianarantsoa, Madagascar.
The dimensions of the crystal are 20 mm by 12 mm high. The image width of the detail is approximately 5 mm x 3 mm.
In fact, we’re dealing here with ‘table-top’ photography where the same technique as for ‘studio-photography’ is valid. The object we wish to photograph doesn’t move.
If we’re able to use a solid tripod, a remote exposure lever and setup the object vibration-proof the exposure time for our camera is less important.
We can choose a small aperture (fe. F36) to obtain a good depth of field and resolution. The exposure time can be set in function of light measurement.
Quartz (SiO2) is a very common colorless mineral with a vitreous luster. You can look through very nicely. Desirable and unfortunately also quite rare are sometimes the wonderful inclusions in the quartz, they are undamaged, very small and often have an unusual appearance. A good example is the mineral hollandite, presented here as tiny stellate fibrous clusters.
Hollandite is a member of the cryptomelane group of minerals and is an opaque silvery-grey to black coloured barium-manganese oxide with as chemical formula Ba(Mn4+,Mn2+)8O16 . It appears mainly in manganese deposits and is derived from the dissolution and oxidative decomposition of iron-manganese rich calcite host-rock cements and vein fillings (Milodowski et al. 1998). Hollandite is an uncommon monoclinic mineral with a metallic luster, a good cleavage but quite fragile.
The quartz crystal has been polished to make the hollandite more visible. This will not make the photographic aspect easier as polished surfaces show a very strong reflection, even in daylight. Light is just something we need a lot in photography. Backlight is absolutely necessary to express more attention to the inclusion. No matter how you put it, no matter how you setup your lights, you’ll always have reflections. The difficulty is not having burnouts while all facets are clearly visible. Besides that, the final object, being the star shape of the hollandite must be visible.
However, to obtain the result above, more was needed than simply one clicks on the release button. Not only the presentation of the specimen is important, but also the lighting. A lot of light is needed to see into the depths of the quartz. The disadvantages of too much light are burnouts, something to be avoided at all times, certainly in this case, where no reflections of any crystals are possible.
To photograph this crystal, I used a Nikon D300s SLR camera with a light sensitive 105mm macro lens mounted on a tripod. The quartz is mounted in a Kaiser Dome Studio Light tent in order to create a diffuse light. As extra illumination a regulated halogen light source with blue filter was used. The light was bundled and injected through the bottom of the quartz. The position of the crystal was chosen in such a way that the inclusion came in front of the back of an internal crystal face.
Three identical images, using spot meting and with different exposures, were made using the camera's bracketing option. Those images were merged into a HDR (High Dynamic Range) software package to obtain a 32-bits/range tone mapping image with a perfect overall illumination. This image was used as a second separate layer for further improvement in PhotoShop. For the main layer the image without correction was used. Best parts of both layers were selectively merged into one image.
The hollandite inclusion is photographed with the use of a semi professional Zeiss Stemi-2000c microscope. Because the microscope and not the camera is the determining factor to get a good quality of image, a good pocket camera would do the job very well, therefore, my Nikon Coolpix 4500 pocket camera is installed on a third ocular. For illumination a ‘cold’ halogen ring light and a fiber optics was used. The latter injected the light through the bottom of the crystal. To obtain a good depth-of-field, the camera was set manually using a long shutter time (1/8 sec) with the smallest possible aperture.
The fibers of the hollandite are very thin and due to the metallic luster, a higher magnification of the microscope was needed to obtain a good resolution. The higher the used magnification the more difficult it is to get a good depth-of-field with a good resolution. Therefore, the uses of multi-layering techniques were stacking of images are inevitable.
There are several ways to do this. Combine Z, Helicon Focus or working with layers in Photoshop are only some of them. When or why to use a particular technique depends a lot on the image and the crystal. A lot of experiences, patience and trial and error are the only ways to become familiar with these techniques and to obtain good results.
As before, there’s only one sine qua non… every image you’ll take must be sharp without too many reflections or burn-outs. The latter is very important as CombineZ will generate nasty artefacts which are almost impossible to remove later on.
The final image of the hollandite inclusion is the result of three separate images.
For the finishing touch some typical PhotoShop techniques as correcting the histogram, removal of imperfections such as scratches, dust, hairs,… and eventually removing noise and a selective sharpness.