Stands

Stands for specimen imaging should make rapid recording of high quality specimen images easy. The prices cited are based on US websites accessed January 2022. They do not include taxes or shipping costs. Work with stores in your own country to determine how much appropriate equipment will cost your institution.

Considerations

The stand must provide rigid support for the camera and have an attachment for holding the camera-lens combination out over the specimen in a horizontal position. The equipment shown in the image also has arms to hold lights on both sides. Having lights on both sites is essential for even lighting. If the lights are on separate supports, their position needs to be checked before starting specimen imaging. Having them attached to the base of the camera eliminates this need. The stand shown, a Smith-Victor 42″ Pro-Duty Copy Stand Kit, costs $460 and includes 2 LED light panels on flexible arms. 

The base plate on which the specimen cradle is placed must be horizontal. To check that it is so, purchase a circular level (see examples on the right) or use two linear levels placed at right angles to each other. The circular levels shown in the figure range in cost from $7-15. They are often carried by “Do it yourself (DIY)” stores.

Camera support

Both the vertical support and the arm that attaches the camera to the vertical support must hold the camera in the right position for at least two days, preferably longer. You should, of course, check the camera’s position, level, and focus regularly, perhaps once a week, certainly once a month.

If you see problems with the images when you record them, stop work immediately and address them. Even if you do not, it is good practice to recheck the camera’s focus and levelness perhaps once a week, certainly once a month. For focusing problems, adjust the lens. If that does not work, try changing the camera’s height.

The arm must be long enough to hold the camera over the center of the specimen and have an appropriate attachment for the camera. The kind of attachment will depend on the camera-lens combination. DSLR cameras are attached to a hole in the base of the camera. Cellphones and tablets are held by devices that grip opposite sides of the device. Check that the attachment you are considering will allow the camera to be held horizontally over your specimen; some do not do so.

Autofocus will make minor adjustments for distance but, with some equipment, the problem is that the camera does not remain level. Autofocus cannot adjust for such changes. To check whether it is horizontal, use a circular spirit level such as those shown above. It will check that camera is horizontal in two directions at once.

Lights

The imaging equipment should provide consistent, even lighting over the whole specimen. “Consistent” means the same no matter what the time of day. The easiest way to achieve this is to have an imaging area with no windows and ceiling light that is even or, if that is not feasible, low light. If the room lighting is low, it should be overwhelmed by the image lighting.
The lights chosen should maintain their color temperature over time. LED lights can provide more even lighting at lower cost than incandescent or fluorescent lights. The equipment shown includes uses two lights, each incorporating 96 individual lights that provide lighting with a color temperature of 5600°K.
With DSLR cameras, the camera’s aperture and speed can be varied. Smaller apertures and slower speeds provide greater depth of focus, which is significant if photographing thick specimens or those that are not well-flattened. There is no way round the problem for mass digitization work, but high light levels minimize the problem.

Color calibration

To ensure that images accurately reflect the colors of an object, color calibration is necessary. The easiest way to include color standards in your images. Calibrite makes these in several sizes. The most useful size would be the nano, 24 x 40mm ($189). This is small enough it could be placed on the cradle wall for routine specimen imaging. The next smallest size, the mini is 63.5 x 109.0mm, but it only costs $69.  It would need to be placed on each specimen just before recording its image. Each of the panels is carefully calibrated for color and saturation. The company makes free software that, when installed on your computer, compares data in the software with data from the camera to modify the data on the recorded image so that the image displayed is more accurate. There is one other factor in how colors appear, and that is the user’s screen. Only the user can address that.

Ruler

Specimen images are of much greater value if they include a ruler. With a ruler, measurements can be made using ImageJ or similar software. I recommend gluing the ruler to the wall of the specimen cradle and positioning the camera and the cradle in such a way that the ruler is always included in the specimen images. Having measured hundreds of specimen images, I strongly recommend using one of the linked files (in & cm; cm only) to print a white on black ruler, after modifying the white rectangle by adding the name of your herbarium and its logo. I see no point in stating “copyright reserved” below, as the original did. It would be reasonable to add “CC BY-SA”. Follow the link to find out what this means.

Rulers should be sized to exactly 10.75 inches long by 1.0 inches high for printing

Print rulers on paper at least 12 inches long in one dimension unless your printer can print right to the edge of an 8.5×11 inch sheet of paper. ­

Use a paper cutter to cut just inside the black margins of each ruler.

Miscellaneous items

Camera control: It is critical that the camera not move when an image is recorded. Bluetooth remote controls can be used with cell phones and tablets. For DSLR cameras, a shutter release cable will be needed. Make sure you purchase one that works with the camera you will be using ($10-$27).

Camera-computer cable: It is best to transfer the images to the computer as they are recorded. This requires a cable long enough to connect your camera directly to the computer being used for image capture (~$25). Make sure you purchase one that fits your camera and is long enough to reach the computer you will be using.