Which lamps for Ilford Multigrade 500h?

I just bought a used Ilford Multigrade 500h on an Omega D5. A sticker on the inside of the head says (repeatedly, in several languages): "Only use 120V 300 watt lamps". The gal I bought it from had always used the 300 watt lamps, and she even gave me two unused 300W spares.

Since she didn't have a manual, I downloaded my own and was surprised to find that it calls for: "2, 120V 150W ESD quartz halogen projection lamps with dichroic reflector". The back of the power supply says its output is 400W.

The unit bench tests well with the 300W lamps and the lamp house is very clean with no signs of overheating or damage. I haven't started printing yet as I am waiting for appropriate lens plates. I did find another thread on APUG that mentions this issue, but only briefly and without much of a conclusion.

My inclination is to get a pair of 150W lamps and that the sticker is wrong, but before I do I'd like to know if any of you who use this head know any more about this large discrepancy in recommended lamp size, and what lamps you use.

Thanks and best regards,

Dave

Hi Dave

If I recall correctly, Ilford changed the design at some stage from 150W to 300W bulbs.

I use the 500H head with 300W ELH bulbs (made by GE). My 500S power supply says on the front and back that it is 600W. I guess it is possible that you have a mixed set - an older power supply and a newer head... That might explain the discrepancy between the label in the head and the stated power consumption of your supply.

Ian

Ian is right on the 300W ELH bulbs for the 500H head. When I was working for Ilford I recall one of the big selling points for the MG500 head was having the same exposure time over the entire contrast range while keeping exposure times short and this came from using the 300W lamps, not 150's. I have also used an MG500H head for my own work for over 15 years and have always used 300W ELH lamps.

I have used the Ilford 500H head for many years, and I like it very much. In mine, you can use both the 150W ESD and the 300W ELH bulbs. I found that the 300W ones are too bright, and my dodging and burning times were too short at lens' optimum apertures. The 150W are fine, but I still prefer to use a 0.3 ND filter (Rosco) in the light mixing chamber.

The key difference between the ELH and ESD bulbs is their lifetime and price. The rather expensive 150W ESD don't last more than a few hours, perhaps 12 hours worth of exposures. The much cheaper 300W ELH seem to go forever (50 hours or more). Pricewise, despite less electricity used, the lower 150W bulb ends up costing more than the 300W one, even if you disregard it's lifetime. Bear in mind, they are both 120V.

Rafal

I have two MG500 systems of differing vintages and both are 2x300W, with the power supply rated at 600W.

Tom