cooling fan on Durst 138?

[Luis-F-S]

[QUOTE=ruilourosa;1355023]

I was not being critical of what you did,

Yes you were!

No dude when I'm being critical I leave very little doubt. Frankly I really don't care what light source YOU use because I have complete enlargers that I can use, which is all I really care about. Until we actually see prints made with your light source well just have to take your word for it!

[Luis-F-S]

Do dichroic filters last decades of use?

I don't know, but almost anything with color fades with exposure to light.

My DeVere was made in 1994 ish and the filters are fine. That's two decades!

[Drew Wiley]

Dichroic filters do not fade. They are optical coatings, not dyes. But with excessive heat over a long time, little bits of coating can gradually spall off the glass,
affecting performance. There are a couple other inherent issues. One is the incidence of the light passing through them, the other is that they can shift spectral
sensitivity with temperature. All this kind of thing can be studied in optical engineering manuals. Most halogen bulbs employed with these are "blackbody" light
sources producing a continuous spectrum, which then is then subtractively filtered for only the three general wavelengths which color printing materials respond to. But LED sources are discontinuous, with only a few of them beginning to fool the eye into a sense of natural light. So even a relatively high CRI can be a bit deceptive in this case. I personally suspect it's a bit premature for LED colorheads, but certainly applaud anyone willing to experiment.

[ruilourosa]

[QUOTE=Luis-F-S;1355067]

No dude when I'm being critical I leave very little doubt. Frankly I really don't care what light source YOU use because I have complete enlargers that I can use, which is all I really care about. Until we actually see prints made with your light source well just have to take your word for it!

I had no doubts, and you do seem to care

and take my word for it, the "dude" is honest most of the times

i am very willing to experiment as a strong believer in research and a reflexive practice towards arts, i do my testing and my thinking, and my enlargers are all quite fit to BW printing (the one that i do) and as are the various enlargers in the university where i teach. I follow the way of Richard J. Henry and Jonh B. Williams in the matter of technique: i test! and if it works and suits me, fine, otherwise i move on. Like i´m doing with this thread:

Cheers!!!