How I Updated My UV Printer With LED Lights
In fact, my very first video workshop was on how to create a DIY UV Printer for alternative photographers. This article is an update for this workshop and even if you didn't purchase the detailed step-by-step video workshop, I think you will still gain a lot of value from the information in this article. All of the information in the DIY UV workshop is still valid and this new information about how to use LED lights is simply an update based on the new technology that is available now. If you are interested in learning how to make platinum and palladium prints, I have a step-by-step guidebook and video workshop that will guide you through the entire process. Please read the entire article before sending questions. I promise you that everything you need to know is contained in this article and I use this exact setup to make all of my platinum and platinum/palladium prints. So far, I have made over 125 prints with this setup and all of them are flawless. I don't mind answering questions, but I think this modification is so simple that photographers tend to overthink things and start to question it or be influenced by other people in online forums. I promise, it is simple and it works.
For my fluorescent black lights, I used GE Lighting Black Light Blue (BLB) # 34747 20-Watt fluorescent bulbs that emit at UV-A 368nm. I have made a lot of platinum and platinum/palladium prints with these bulbs and I really like them. So, I knew that I wanted to make sure the new LED lights could produce a very similar result. The very first thing that I researched with the light spectrum of the LED lights as compared to my BLB bulbs. Light Spectrum Reference When I started searching for an LED replacement solution, I knew that I wanted to find lights that were within the UV-A spectrum for sure and if possible, something very close to my original GE bulbs because I really like the look of my platinum prints. I was also hopeful that I could reduce my standard 10 minute exposure time with the new LED lights. Faster printing times are advantageous especially for platinum prints because of the moisture in the paper and sensitizer can dry out over time and produce prints with a weaker DMAX.
I finally found some LED lights that were physically built very similar to fluorescent lights, so I knew this was the lights that I wanted to try first. My original GE BLB lights were rated at 20 watts each and the new LED lights were rated at 9W/395nm, but you have to keep in mind the rating differences between fluorescent and LED lights. I did a quick conversion and determined that the 9W LED lights would be equal to about 40 watts in fluorescent giving me twice the light. In theory, this should reduce my printing time significantly which is highly desirable for platinum printing as previously noted. Only final testing would confirm if the new LED lights would make a beautiful platinum print and if my printing time was reduced. Hang in there and I will share my results with you. I was able to find a very interesting LED replacement (Barrina UV LED Blacklight Bar, 9W 2ft, T5 Integrated Bulb, Black Light Fixture) on Amazon. They come with a three-year warranty and rated at an astounding 35,000-hour lifetime capacity. The physical layout and the light spectrum should work very well, but there is no way to know unless I simply built the unit and made some real platinum prints. My original GE lights were 2 feet and the new LED's lights were also 2 feet making the conversion very simple and quick in my existing UV printer. REPLACEMENT PROCESS
You can see in the picture to the left that I built my UV printer with a hinged top. So, I simply removed the hinged top and went and cut a new piece of plywood to the same size and placed the new LED lights in the same manner as the BLB fluorescent lamps. My bigger UV printer will allow me to make platinum prints up to 20" x 24". I actually built two UV printers, one for the bigger prints, and one optimized for 8x10 prints that I used in my Sprinter van when on the road. The design was exactly the same for both UV printers. Note that I had a total of 10 20-watt BLB bulbs in the larger UV printer. In the new LED solution, I ended up only using 8 lights spaced 2.5 inches apart over the 22-inch width. In the images below, I laid out the new LED lights and got them all connected together in about 20 minutes.
In the image directly below this is what the lights looked light when they were all connected in series and mounted on the new piece of plywood. These specific lights allow up to a maximum of 10 lights to be connected together in series.
The entire update project took about 45 minutes and that included the time to gather the tools and also cut the new piece of plywood. If I determine I want more lights, I can add up to two more at a later time.
I proceeded to perform some exposure tests to identify my new standard printing time. Remember with my old BLB system, my standard printing time was 10 to 11 minutes. With the new LED system, my standard print time has been reduced to an amazing 3 to 4 minutes! As noted above, this is a good thing for platinum printing because the sensitized paper retains its moisture profile better with shorter exposure times and this is hugely beneficial for getting those darker and richer tones. Next, it was time to make a real test print using an existing negative and comparing it to a previous print made with the BLB bulbs. I kept literally everything the same except for using the shorter exposure time. The top print was made with my BLB bulbs with an exposure time of 11 minutes as you can see from my notes on the print. The lower print was made with the new LED lights with an exposure time of 4 minutes. UPDATE I have now made over 125 platinum and platinum/palladium prints in this UV printer using a variety of different papers and developers and it works fantastic and without a single issue. I can say based on first hand experience using these specific LED replacement lights has been one of the best improvements of my workflow in many years. I have significantly shorter printing times which leads to richer tones and deeper blacks. If you are interested in learning how to make platinum and palladium prints, I have a step-by-step guidebook and video workshop that will guide you through the entire process.
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Keywords:
alternative photography,
analog photography,
black and white,
darkroom,
fine art,
palladium,
platinum
Comments
Tim, thanks for the prompt and reassuring response. I'm taking the plunge and purchasing these for my platinum/palladium prints. I have an extensive woodshop in addition to my darkroom, and build furniture as one of my other pursuits, so I can build the UV box "with my eyes closed," as it were. I'll be sizing mine for the largest contact frame I use, which is 11x16. But I have no background in electrical wiring, so I like the fact that I don't have to do any wiring with the LEDs, as they come ready to be connected and plugged in. One last question, though. Do you recommend a fan for these lights, or is the heat generated low enough not to be a concern? Thanks in advance.
Hi Mike, as I mentioned in my comment to Martin, I have made over 100+ Platinum, Platinum and Palladium prints using a variety of different papers and developers without any type of issue. It works great and I should mention that my printing times have been reduced drastically. I just made 10 new prints this last week and I am working on two new Platinum projects at the moment as well.
Hi Tim, I'm very intrigued with your alternative use of LEDs - bravo! There is a lot of discussion on other forums about the importance of placing traditional bulbs as close together as possible to create overlapping diffusion of the light, and to prevent banding. However, I noticed that you spaced your LEDs 2.5 inches apart - quite a bit further apart than what I'm accustomed to reading. I gather this was because the LEDs were stronger than the original bulbs, hence you needed fewer of them, and had to space them further apart as a result. I also gathered from your response to Martin's question that you haven't experienced any lines with them being this far apart. But do you see any unevenness at all, or is the distribution of exposure even across your prints so far as you can tell? Many thanks in advance.
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