UV Enlargers - Part01: A 100W UV light source

[@piet-wj9pd]

THX 👍

[@christophguettel1486]

Thank you very much, this looks really promising! I tried sth similar myself, but the exposure times were very long (much longer than 17min). I believe quite a lot of UV light is blocked by the condenser and the enlarging lens, so I am very much looking forward to the next part of your video to see who you tackle these problems. Greetings from Germany. Chris

[@aomanchutube]

I'm using a 3000lm DLP digital projector. It can easily do a 12x14 in less than 10 minutes. But you gotta use the "New Cyanotype" formula which is pretty simple to make actually if you look at Mike Ware's site. But anyway, I am using the projector as is with no modifications. In parallel I'm trying to convert it to UV just so I can maybe make it easier to focus on the correct wavelength? So I basically have the same set of items he has on this video. I'll remove everything from the projectors's optical path from the lamp and replace it with just the LED. That big LED lens is very thick I think it's not actually necessary if you make a light tube. I'm making mine from aluminum. I bought some mother's polishing compound and you can make aluminum mirrors with it. So just make a little rectangular tube with inner mirror surface. That should reflect 90% of UV light. It will form a homogeneous but expanding beam that you can then point at the DLP dmd chip. The chip acts like a mirror, but probably a little more lossy. But I figure this, a DLP projector is not supposed to blind people with UV light. So an actual UV light LED probably emits much more UV light? In fact I did a test of this. I turned on my 380nm LED and placed a cyanotype sensitized paper on it. Within 2 seconds the spot immediately close to the LED turned Prussian white. Not sort of light blue. I mean white. I thought maybe the chemistry has burnt off because I saw some vapour coming off of it (using welding helmet as PPE). But no, after about a week of keeping the paper face down on my desk it turned blue again, deep blue. It has some slightly different color because I think the rest of the paper is still not exposed. I was experimenting and it turned blue, but probably still sensitive to UV is what I mean. Ultimate goal is to do Carbon transfer with it. I also tried a 1000 lumens LED projector and it worked too. I made my first image from it actually. It was a 3x4 image. So yeah those things are actually usable for exposing prints.

[@saidanehabib]

Thank you so much, no need to wait you can go ahead and try your projector by using the fast cyanotype formula. Raise the PH of the citrate to a value of 2 to 3, coat your paper, and expose for around that range of time. You should be able to produce a 4x5 inch image in 5 minutes. After the exposure spray the ferrycyanide, the results are amazing. I believe there is enough UV light that passes through the glass to produce beautiful photos in a very acceptable time. Greetings from a Tunisian in Texas, Habib.

[@saidanehabib]

@@aomanchutube The DLP projector are powerful especially when you remove the UV filter and the color wheel. I have a few laying around to play with but never found the time. The 100W UV chip LED can be used for both analog and digital, the new formula is nice and works, but I find it messy, sensitized paper turns blue fast in contact of just the air. Sensitizing paper with just the citrate, exposing and then developing with the ferrycyanide give beautiful clean photos in an analog enlarger.

[@christophguettel1486]

@@saidanehabib Thanks. I will try it! What size of negative did you use?

[@saidanehabib]

@@christophguettel1486 This sample is from a 6x4.5 cm, the one will build later on will take large format if we need to.

[@dewskyroy3445]

top merci !

[@saidanehabib]

Merci beaucoup.

[@mohamedoubihi173]

Hello Sir What diffusion angle you use for the led lenses...60 or 90 or 120 degrés?

[@saidanehabib]

Salam, I got a $10 100W UV LED from ebay, they didn't mention the diffusion angle on their listing. I put a 77mm lens in front of it. You can contact me at this page and I'll give you the links of what I bought: facebook.com/groups/alternative2