Many alternative photographic processes rely on ultraviolet exposure to record an image. These processes were historically exposed using the Sun, though many printers today prefer to use purpose-built exposure units. The radiated UV of both modern exposure units and the sun can vary, which creates a process that is difficult to control. I built this UV integrator to control my carbon transfer printing, which I expose using the Sun. This meter would be of use to any artist practicing an alternative process exposed via UV radiation. This includes (but is not limited to) cyantotype, platinum-palladium, carbon transfer, gum bichromate, kallitype.
The meter will keep track of how much UV radiation is incident on the sensor over a period of time. The number that is reported is in arbitrary units, but will be consistent at different irradiances. This means that you could determine the required exposure for a negative using one light source, then expose the same negative for the same number of units using a different source. Each unit is approximately 3.27 µW/cm^2, though it is best to think in terms of arbitrary units.
The project is based around a VEML6070 UV sensor and an ATMEGA328P microcontroller, which allows some freedom for expansion if one wishes to add other features. The spectral sensitivity of the VEML6070 can be found in the datasheet. The design of the meter is provided below for free. This includes a schematic, a breadboard layout, and the microcontroller code. Programming a microcontroller can be overwhelming if you have not done it before, so I have made pre-programmed chips available below. This is ideal for electronics hobbyists that do not have experience with microcontrollers. I have also designed a PCB, which is also available below. Finally, everything needed to construct a functioning meter is also available as a kit. All you provide is a soldering iron and solder. A laser cut case is included in the kit.
Most items are currently unavailable due to a re-design of the integrator. The firmware will be unchanged in the redesigned unit and pre-programmed microcontrollers are still available.
Schematic, Breadboard Layout, Code
Free
Pre-programmed Microcontroller
$15
UV Integrator PCB
$15
UV Integrator PCB + Pre-programmed Microcontroller
$25
Complete UV integrator kit
$75-100
Assembled UV Integrator
$125-150
Domestic Shipping
I ship via USPS Priority Mail from the Austin, TX area. Shipping is a flat-rate anywhere in the US. $5 will be added for the microcontroller or PCB, $15 will be added for the kit or assembled integrator.
International Shipping
International shipping is available via USPS First-Class or Priority Mail. $25 will be added for First-Class Mail and $60 will be added for Priority Mail.