Darkroom
With the advent of the digital darkroom, we've removed the enlarger and supporting equipment for our small (10x12) chemical darkroom, and use the space for exposing and developing photoresist. (The digital photography efforts still use film, but we digitally scan the film and print upstairs in Mary Anne's graphics work area. )
Exposure
 At first, we used a small black light unit (Letralite) purchased from Photobrasive. For very fine detail, it is necessary to hold the resist and film positive together with a fair amount of force. Consequently, we now have a nuArc vacuum frame and 1000W light source. Developing times are running about three minutes. To this point, everything has used Photobrasive self adhesive UltraPro 3, 4, 5, and 6 mil resist, just for the convenience of not having to apply the glue.
 The vacuum frame folds up and out of the way to allow the workstation to be used for peeling resist and remasking. Diamond burr tools shown in background.
The electronics workbench is also in the darkroom and supports design and construction of LED arrays, among other things.
Development
  We use an electric pressure washer at 1500 psi to develop the resist, at about 105 degrees Fahrenheit. These higher pressures permit greater detail and faster development. Time is important, since long wash times will tend to destroy the resist. We typically wash for about 28 to 36 seconds, depending on the level of fine detail (longer). The wash box is a modified translucent storage box ($5) with clear window added ($7). Works really well. I'm remodeling the system to add a rear (external) safelight and to provide an internal screen for supporting the resist. The very fine textures require inspection during the development process.
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