• Welcome to Photrio!
    Registration is fast and free. Join today to unlock search, see fewer ads, and access all forum features.
    Click here to sign up

Durst 1000 - Blue filter

SMBooth

Member
Allowing Ads
Joined
Jun 29, 2008
Messages
1,192
Location
Melbourne, N
Format
Multi Format
Ive put together a darkroom, my 'new' enlarger is a Durst 1000 with condensers and bulb which requires a filter set for contrast. I'm curious to know why previous user inserted a blue filter between the lamp and condenser. Should I remove it to get correct contrast filtering or does the blue filter improve something I don't know about.
 
it's supposedly better to focus with blue light because that is the color that photographic papers are traditionally sensitized to see. focusing with white light, in theory, is less accurate because the different wavelengths of light focus at different distances.

that said, in practice, I have never seen a difference.
 
A blue filter would increase contrast with variable contrast paper. Is the light source quite green or yellow without it?
 
The heat absorbing filters I know have a greenish-blueish cast. Maybe the OP could comment if the filter has a colour cast or a strong distinctive colour?
 
OTOH if the filter is a colour conversion filter (i.e. a KB3 or so) the former user might have tried to enhance contrast. A frosted bulb with 150W says nothing about the colour temperature of the light; maybe it's not a dedicated bulb for enlargers and the spectrum is simply to warm.
 
Obviously there are thousands of irrational reasons the filter could be there. If you are interested in some rational reasons, I can suggest the enlarger may have been used as a sensitometer.
 
SMBooth said:
No bulb is a Phillips Photocrescenta PF 605, filter is pale blue not unlike a 82C filter. It not heat glass its tape directly to the top condenser.
Click to expand...

My understanding is you're not kitted out for colour printing (correct me if I'm wrong), but maybe the filter was to provide a slightly cooler light to the warmer/reddish lamp? Much the same as you'd use an 82 A-B-C filter to cool down an overly red scene. Another theory is to correct for visual colour deficiency ("colour blindness"), much the same as a few people where blue-tinted glasses, others still wear rose-tinted... there are likely thousands of reasons.
 
munz6869 said:
I have a blue filter accessory for my Grain focuser, and folks have often commented how sharp my prints are... Of course I have never ever used the thing (and why would I? It just makes everything annoyingly darker!).

Marc!
Click to expand...

My experience as well.
 
SMBooth said:
No bulb is a Phillips Photocrescenta PF 605, filter is pale blue not unlike a 82C filter. It not heat glass its tape directly to the top condenser.
Click to expand...

The bulb seems to be the correct one. The fact that the filter is taped to the condensor shows that it was not intended by DURST. Just remove it.
 
munz6869 said:
I have a blue filter accessory for my Grain focuser, and folks have often commented how sharp my prints are... Of course I have never ever used the thing (and why would I? It just makes everything annoyingly darker!).
Click to expand...

Gene Nocon recommended the blue filter in his book Darkroom Printing. He suggested that it was better to focus using the same colour of light which the paper is sensitive too.

It doesn't matter if the light is filtered at the source or at the grain focusing device but I would remove it from the enlarger to make an actual print.


Steve.
 
You must log in or register to reply here.
Menu
Log in
Register