Today I bought and collected a second-hand Durst C35 enlarger. It needed a new bulb, and the manual says very little about bulbs except you must use a MELAMP 55.
Users in some forums, including this one, say that compatible bulbs are difficult to find, or expensive. A little research tells me that the correct bulb is 55W, with an E26 Edison screw fitting, and an R20 glass envelope.
Thanks to Don’s Bulbs, it was easy to find out that these are all standards, and R20 is more commonly known as R63 or R64, because the widest part of the glass is 63 or 64mm in diameter.
And I’m delighted to say that Tesco (and probably almost every other retailer of domestic bulbs) have R20 bulbs with an E26 screw – albeit in a 60W version. If you can cope with the tiny difference in power, you can pick up two of these for £2.
The only snag I can see is that these bulbs probably have a different colour balance from the original Durst bulbs. I print in black & white so it doesn’t matter to me, but it might if you were to print in colour.