Re: Seeking: (1) orange LED safelight, (2) wire coating rod
From: "Ryuji Suzuki" <rs@silvergrain.org> > A standard safelight for infrared material is dim green light, > but uses Wratten 7B or similar green filter with spectral > transmission peak at around 510 nm for best night vision > (rod sensitivity) and good infrared blocking > performance. www.thorlabs.com or www.edmundoptics.com certainly have filters for your application. You might look for a BANDPASS (interference) filter. > > However, for my particular dye (spectral absorption of about > 700 to 850 microns on silver halide emulsions), it is probably > best to use 600-650 nm range for safelight. This is because, > with a fast emulsion, 510nm light can fog the emulsion (AgBrI > emulsion can be sensitive to about 540nm). Red LEDs contain > spectrum beyond 700nm and this will fog the emulsion. So, I'm > thinking that orange LEDs would allow me to coat the emulsion > in quite high level of illumination. I believe those (non-white) high-power LEDs don't emit any significant NIR radiation. Take a look at the spectrograms of a LUXEON (http://luxeon.com/). By the way their amber types (~590nm) are pretty monochromatic (bandwidth around 30nm or so). May I ask what particular sensitizing dye you use? > I have no problem in buying bulk LED components and soldering > them myself, but I wonder if such an orange LED safelight > exists as a commercial product to save my time. www.acriche.com/en/product/prd/acriche.asp sells high-power LEDs that run at AC 100-230V directly. > Now, I've been using a glass rod wound with silver wire, but > this is such a quick kludge and I'm looking for something > better. Does anyone know where I can buy a glass coating rod > with a handle pre-wound with 316 stainless steel wire? (Or, > teflon coated stainless wire?) You may try these: www.dynesonline.com/metering_rods.html www.sinotime.8k.com/photo.html www.rdspecialties.com/Page.asp?Script=1 An alternative would be using threaded rods. As of now I've been unable to locate them, but there certainly exist PA-6, PTFE and other plastic threaded rods which could be easily cleaned. Martin
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