Bob F. said:
Colour papers have a sharp dip in their response at around 590nm which allows the use of sodium vapour lamps and suitable LED based safelights. As others have pointed out, you need to test your materials, especially with the sodium lamps as they reportedly drift in colour as they age.
Cheers, Bob.
P.S. Use of a sodium vapour lamp is why I can read my handwritten notes even when using VC B&W paper... their sensitivity does not reach much above 550-560nm - I find the red filter that comes with my Duka unnecessary.
Bob. I too use a DUKA. Mine is a DUKA 10 that I got secondhand from Nova. You may have seen my replies elsewhere praising its light intensity while still preventing fogging.
Well disaster struck last night. The sodium bulb went. I have only had it a year and used it maybe 150 hours max - probably less. Although it was secondhand, I has assumed( probably naively) that the bulb was near or nearly new. Equally naively, it would now seem, I had assumed that if the whole lamp was £75 secondhand then a new bulb may well be at least half of that or even most of that. So today I set about checking on suppliers and prices. Imagine my shock at seeing prices for new bulbs at over £200!Silverprint and Nova. One supplier that I had used for an enlarger lamp and found to be very reasonable told me that he had stopped stocking the Duka bulbs because he felt that the manufacturer was killing the market by the prices asked.
It would seem that either I take the plunge and pay an extortionate price for a new bulb or buy a complete fresh lamp secondhand and throw away my old one and take the risk that the bulb in the secondhand lamp is relatively new.
Can I ask where you obtained your lamp? How many hours have you got from it and if there is any way of checking how many hours a secondhand bulb may have been used for. I spotted one place in Dorset advertising a secondhand DUKA 50 as mint and unused for £65. Sounds quite good but it begs the question of (1)how do they know it to be unused unless they have personal knowledge of the previous owner and (2) why didn't he/she use it?
If a new bulb gave say 1500 hours of use and could be obtained for even £150 then the cost per hour becomes reasonable. Currently my DUKA runs out at about 50p or even more per hour.
Any help and advice would be gratefully received.
Pentaxuser