Microfading Tester International Discussion Group

I have a few questions regarding the standard Whitmore design MFT system that we have at Winterthur.

1) What type of Xe lamp have people selected for MFT using the Whitmore design: standard or ozone free? The latter generates less UV, but unless one is interested in UV induced fading or optical brighteners visible light (400-700 nm) should suffice.

2) Has anyone used a 100 W Xe arc lamp instead of the 75 W lamp that seems to be the standard choice?

3) Our Whitmore MFT system at Winterthur also has a water filter installed on the Xe arc lamp housing, but the filter is empty and infrared radiation is instead removed by a glass optical filter. Have MFT users with similar systems removed the water filters since they are no longer needed (and generally require some type of temperature stabilized water circulation to use)?  

Thanks in advance for any advice you can share!

Best regards,

Mike Crawford

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Michael Crawford
SRAL Volunteer
Winterthur Museum, Garden & Library
Glen Mills
United States
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Jenny Kim
Assistant Scientist
Getty Conservation Institute
Los Angeles
United States
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Original Message:
Sent: 6/5/2026 11:36:00 AM
From: Jenny Kim
Subject: RE: Xe lamp and water filter for Whitmore MFT?

Hi Mike,

We had the standard xenon-arc lamp (#6251NS, Newport), but we've recently changed to the ozone-free xenon-arc lamp (#6263, Newport). The reason we changed to the ozone-free lamp is occupant health, as it reduces ozone generation from UV below 260nm. Above 260nm, the irradiance of the #6251NS and #6263 lamps appears similar, so we apply a UV filter and a hot mirror to block UV.

Regarding power, we use 75W lamps. We operate our Whitmore system at around ~800 mlm, and 75W was enough to reach the light level. Also, we feel like we don't need to expose our samples to a higher light dose. However, when a light bulb deteriorates, we increase our wattage slightly higher with a digital controller. 

Our Whitmore system also has a water filter; however, we don't use it due to the complication of connecting to the DI water. We spoke to Newport, and they suggested removing it if we don't use it, since it can reduce the light output. We use a hot mirror to cut the IR, and it seems sufficient.

I hope my answers are helpful, and I am happy to discuss more if you have any follow-up questions.

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Jenny Kim
Assistant Scientist
Getty Conservation Institute
Los Angeles
United States
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