Discussion in 'Talk About Large Format Gear' started by David M, Sep 16, 2018.
How do you get on with Multigrade printing and LEDs ?
A lot better than I did with the fluorescent light. This had the wrong colour temperature for the Multigrade system, which works on about 2700K - the colour temperature of an old incandescent pearl bulb. So I couldn't get a full contrast range with it. And the contrast I could get didn't vary in even amounts.
When I found I could buy LED bulbs rated 2700K, rather than splash out on four plus holders, I bought a single bulb and tried it in my 35mm Leitz Valoy enlarger to see how it would work with Multigrade. First I did a series of prints with the incandescent bulb in place. I used a negative that I knew printed nicely on grade 2.5. I made a nice print at this grade then using the same time made prints at one grade intervals -doubling the time above grade 3.5. Then I switched to the LED bulb and repeated the whole process. The LED bulb was a bit brighter, but once I'd adjusted the time I made a series of prints with the LED bulb that were identical in every way to those made with the incandescent pearl bulb. Bingo!
So then I went back to the shop and bought the four bulbs, plus holders, that I knew I would need to get even illumination through the diffuser in my home-made 5 x 4 enlarger. And it works very well.
David, I had heard of the multicoloured LED strips you mention But the technology needed to get this to work is way beyond me. So I decided to stick to the simplicity of bulbs and under-the-lens filters.
About 3.25 into the video. How many LEDs?
I make it six rows of five.
I followed the project on Large format forum, they really put some effort into it.
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