I've heard that dichroic filters do age and i've also heard that they don't... Could someone enlighten me: do they change with time like drawer filters or not ?! Many thanks. Awsiya.

-- awsiya (awsiya@fnac.net), April 16, 2002

Answers

Dichroic Filters use interference and do not age. Their principle is based on the interferences appearing at multiple reflections between two semi-permeable layers in the filter. Dyed Filters incorporate the filtering substance in the glass and do age as the dyes fade. There have been some color heads that use additive color mixing by means of dye filters (e.g. Philips).

Regards,

-- Thilo Schmid (tschmid@2pix.de), April 16, 2002.

Yes they do age. Not nearly as fast as gels. They should last years, how many is dependent upon how much they are used and the type (how hot is that light source and how good is the cooling - do you keep the fan inlet/outlet clean?) of light source.

-- Donald F Degen (6228fotoguy@attbi.com), April 16, 2002.

Well, Awsiya - the two answers above should clear up any queries on that subject ;-)

Probably, the definitive answer will have to come from the manufacturers of your particular filter head.

Cheers,

-- Bob Francis (bobphoto@techie.com), April 17, 2002.

Well, Bob, exactly ! Cheers, Awsiya.

-- awsiya (awsiya@fnac.net), April 17, 2002.