[QUOTE=jon.oman;1480244]Would this work with an Omega D2v?
Hi, I'm not familiar with the enlarger but I looked at a few photos online and also found a PDF of the manual which showed a close-up of the lamp housing and how to change the lamp. My guess is it could be possible but may need a bit more "engineering" to make it work as the chamber holding the lamp is very much smaller than the Durst 138 housing.
Anyway there are rapid developments happening in LED lighting so you may be able to find a smaller unit with adequate lumens to replace your current globe. What wattage is the recommended globe for this unit? 75w, 150W, 250W?
See this, for example:
Yes, my thoughts exactly. I found one site recently wanting to sell the large 300W replacement globes for Durst 138 for $250 or more. No Thanks!
Originally Posted by Marco Buonocore
I believe it is 100W. I'll have to look at the owners manual....
Originally Posted by Tony Egan
Thanks for the link, that may work as well!
i have done it :)
i replaced the opalbulb with a led spot (app. 15 watt).
i dont know the lumen i dopnt know the ligtcolour but it works very well.
my spot had no diffusor so i used a milkwhite plexi-glass.
no brightness falloff to the borders.
with 4x5 i have enough light (10 sec for 13x18 cm)
but for 24x36 mm i have to expose the baper for 13x18 cm about 30 seconds.
Hi Thomas - thanks for your contribution. 30 secs is still pretty good in my experience. With Ilford warmtone paper I was previously in the 60-90 seconds range for 120 and 4x5 film on 11x14 inch paper. This has come down to around 30-45 at similar apertures (f11-f16) after my conversion. It's good to see a positive influence from changing technology on our world. I'm now thinking about building an 8x10 enlarger using LED lights.
Originally Posted by pcyco
yes it was good to see that we schould not only look at curves and measurements of the light-physics. just try it and lets see what happens.
an other point for me to try it with any led-lamp was that some films have other basecolors (foma - blue) this also must have an influence at the printing but nobody cares.
next thing ist to get a stronger light and building an diffusor head.
edit 2 examples
the ring is 4x5
the grapes are 24x36
both printed on kentmere vc 23x18 cm glossy
the grapes filter 0
the ring filter 4
This idea of using the downlight/spotlight things is great and I/m now thinking of a high-power version of a Varicon head.
However, I'm wondering about the distance from the condenser (via the mirror) -- shouldn't the illuminated surface be on the former centreline of the bulb, in order to be concentrated optimally by the condenser(s) ? With any luck there is so much light power available that this isn't a problem, but it might make a difference at extremes.
I'm also curious about the turn-on delay of the unit. Does the enlarger keep the bulb on all the time and have a shutter for exposures?
the worst thing is the diffusor (plexiglass).
i think it absorbs to much light i think i will look for something thinner. any foil etc. thinner and less absorbing light.
@ martinp: yes i have located the laamp in the axxis of the lighthole with the heatabsorbingglass. aprox. 3 cm away from the diffusorplexi in the filterdrawer.
Thank you for the useful information Thomas. My wondering about the light location was for the OP in Australia! The location of the lamp in his big Durst is further away from the condensers than the usual lamp position, though it still works :)
Hi Martin - the bulb position could be moved as it is mounted to the same metal track to which I have mounted the LED. I'm not an expert on the physics of light dispersion although I wondered myself about this as the opening which used to hold the heat resistant glass (I removed) is much smaller than the mirror and the 5x7 inch maximum format. My test was to expose a piece of zone 5 negative at various times to check for light fall off at usual working apertures. I could not see any with 6x7cm or 4x5 inch formats. My amateur hypothesis is the LED may be more precise and uniform than a bulb as the light is coming from a broader source of LED units from a flat field as compared to the narrow filament of a bulb through a curved surface?
Originally Posted by MartinP
As Thomas also indicated, I was quite precise with the LED mounting hole on the board using a spirit level to ensure the LED was exactly aligned to the square opening in the lamp housing. You can see some of my pencil marks on the board in the photo.