Fluorescent Grow Light Bulbs for alternative printing.

[NHE]

NHE - can you please be specific as to what LED bulbs you have moved on to using that you feel have given you the results you are looking for, how many, and at what distance from your support you have placed them? Also, what exposure time have you been using? I have four fluorescent fixtures holding 2 bulbs each of F-40T12BL 40 Watt - T12 tubes (they are 48 inches). I have them about 5 inches away from the support. I make a digital negative with either Pictorico or Fixxons film and expose the cyanotype for 30 minutes. I am hoping to find a better "LED" bulb that makes my exposure go quicker.

+1, please.

I use this led strip: https://store.waveformlighting.com/p...12527605252198

I cut and soldered a 5m strip (of the 365nm) so the exposure area would cover my 11x14 printing frame. The strips come with adhesive so I just stuck them to a plywood board I had, in retrospect an aluminum sheet would have been better as they didn’t stick all that well. The LEDs get warm but not hot enough that they need a heat sink.

Exposure distance is approximately 2in as that was the closest distance where the beam spread appeared even. As to exposure time, a palladium print will get to maximum density in around 2min through an unexposed area of film and around 5min through a blank area of pictorico. I don’t typically print cyanotypes but if I remember correctly the exposure time would be in the 10-15 minute range.

I have focused more on using film lately, but my longest exposure has been around 60min. That was to get detail in an area of snow with a density of log 2.8-3.0. The LEDs are expensive so it was a tough decision, but it has been worth it when printing negatives with very dense highlights.