[Ripcord]

I've been interested in getting a LED overhead light source to make a new exposure unit and I found this on Amazon. I don't know enough about light wavelengths to know if this would be a good source of UV light for exposing screens. The specs say 380nm which from a little research I learned is in the UV-A range and is toward the upper end of the UV spectrum.

If anyone has more knowledge than I about this and can offer some advice I'd appreciate it. I'd hate to buy it and find out it doesn't work...

 

[sben763]

It all depends on the emulsion you use. Saati PHU is 405nm so 395-405, led have a narrow band on about 10nm. There is a photopolymer I think it’s Ulano 365-375. So you need to email your emulsion manufacture and find out what the peak is for their emulsion sense they all use different sensitizers.

100w(actual wattage) is recommended minimum. There was someone here saying 20w would work but they don’t fully penatrate the stencil. I use 200w and 300w.

 

[Ripcord]

Thanks Sean, this one says it's 1000W which is why I was interested, but it's also a full spectrum, not just UV, so I don't know that there is enough UV output. Is there a source for pure UV LEDs that I haven't been able to find yet?

 

[sben763]

Post a link. 1000w that’s either a full spectrum or a equivalent rating. .5w-1w LED usually equals 10w incandescent. With UV LED it’s more like .25-.5 although still quicker then metal halide as this is due to putting out more of the UVA and less visible light then metal halide.

I went though a few “UV” LED that were labeled UV but only put out purple/blue light and no UV. expect to spent $150 up for a quality 100w die, driver and possibly a housing. If using a flood housing make sure to remove glass. For $200-$250 you can get a 200w die,heatsink, and driver and you would have to make your own reflector

 

[Ripcord]

Sorry, I thought I posted it earlier but I didn't... It's sold as a grow light: https://www.amazon.com/gp/product/B06XBLQV91/ref=pe_88520_267423430_em_1p_0_im?th=1

 

[sben763]

Sorry, I thought I posted it earlier but I didn't... It's sold as a grow light: https://www.amazon.com/gp/product/B06XBLQV91/ref=pe_88520_267423430_em_1p_0_im?th=1

That light is 1000w equivalent. Says it uses 182w. it is a full spectrum so it probably puts out very little if any of the spectrum needed for exposure. The UVA spectrum in plant growth is only important during germination and the first few weeks of growth and then during the flowering stages and the amount needed is extremely low so most led grow light manufactures don't put many or any at all leds in that spectrum and just rely on the small amount of bleed off from the visible light spectrum near the 400nm. Those lights target around the 600nm for rapid foliage growth.

 

[Ripcord]

Thanks Sean. Where did you purchase yours? I don't quite know what term to search for on Google...

 

[Imprintknysna]

Hi Sean please man help us?

I am also in the process of building my own exposure box I had one but it all burnt down in the Knysna fire's last year here in South Africa. We have spend a lot of money on rebuilding the buisness. Please help with links so I can do it right from the start?

I have followed all the chats regarding this subject and all the helpful info you gave but never do you give some links or photos to help out? I understand that tou couldn't but you said the time has passed and you are able to help now. Please man from what I understand you are the pro in this field. I have tried to get prices for proper exposure units but it has to be imported and the cost is just crazy.