Hi,
A reply in particular in my other thread concerning enlarger electronics has me asking about frosted or pearl lamps (thanks Jim Jones).
In some of the Durst literature I have read, in particular a document titled "Collimated light vs diffused light.pdf" there are a number of diagrams and discussion about effectively projecting the filament onto the paper via various lenses in a condenser enlarger.
If there are a number of particular condenser lenses made to suit certain bulb sizes for an enlarger (and enlarging lenses) and also when there is a table in the enlarger documentation which speaks of a 'point light' condenser elements, how much does lamp diffuseness play into things? You are trying to focus a filament onto the paper - not a whole bulb ... (in a condenser enlarger anyway) according to the documentation.
The Durst L184 10x10 enlarger does not have point light lenses. The L138 enlarger does have point light lenses.
As the bulbs are not available, I am looking to make up something. I have bought two different sized lamps (quartz halogen 240Vac). Both are not frosted.
I am off to a local manufacturer within the hour to get them mounted in the housings and will discuss perhaps making a polished stainless reflector - hopefully in an elliptical shape to aid in shoving light into the system. I have nothing to get ideas from so I'm sucking and seeing.
The other thing I'm thinking of trying is sanding the heat shield - effectively making it a ground glass heat shield! I'll buy another piece of glass for that purpose of course. This will diffuse the source somewhat yes?
At the end of the day I'd like to get as collimated and as sharp as possible. Diffusion can be had with a big piece of frosted glass or two in the filter drawer!
Cheers,
Steve
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