Durst 138s + 650 Watt Quartz Super 8 Movie Light

[Robert Oliver]

Just yesterday, I lined the inside of my 138 with 1/2 inch foam like a mixing chamber and installed an off the shelf LED.
Went to make a test print and realized I had ran out of dektol and didn't have time to mix up some from scratch.

My first trial setup has LED taped inside main chamber... Until I can fashion a mount to get bulb into original housing.

I am using original mirror in place. I used a sheet of diffusion gel above top condenser space and a sheet of frosted plexi on negative stage. I will probably add another sheet of diffusion gel on bottom of bottom condenser platform instead of the plexi on the carrier.

Light looks pretty even so far...

[jbmia]

How'd that print come out? Be sure and let us know...

[Luis-F-S]

Next step is to try that or a 300 watt ELH if I can find a replacement heat absorbing glass. Anyone have any ideas on that front?

I have two pieces of heat absorbing glass that I bought years ago that I'm having recut to fit the Lacalo holder. Will ask when I have it recut if it is still available. L

[Robert Oliver]

This a crappy cell phone snap of an 8x10 in the wash water. I did the test with a 4x5 negative holder mask with an 135mm EL Nikkor. It is pretty uneven. I would never use that lens to make an 8x10. I need to test it with a much bigger enlargement. Smallest print I make is 11x14, preferring 16x20 and working my way up to mural size prints.

I have a used 150mm Componon S coming in the mail.

I also did a test of the corner of an 11x14 with an old 7.5" Ektanon and it's much more even.
.

[Robert Oliver]

Tonight I did a couple of quick tests to see if I want to pursue an LED conversion. I was mainly looking for evenness of lighting and if the off-the-shelf LED bulb played nicely with my vc filters.

Bulb is a 5000k Phillips 15w bulb rated at 1200 lumens.

It was plenty bright. Exposure 16x20 was 8 sec at f11 with no filter and #00. 16 sec with #5 filter.

Wasn't going for exact, just wanted to see if filters worked. I will do more extensive testing.

I definitely have major falloff... Part of that is probably bulb position. I just taped it in to see if it would even be worth playing with. I paid $20 for the bulb and $3 for the foam.

I will move the bulb into the lamp house, and will see what happens if I replace the mirror with another piece of styrofoam.

So far so good though... Definitely worth moving to round two.

[Robert Oliver]

Left is #00, middle is #5, right is no filter.

[jbmia]

Thanks for the follow up! Yeah, I'd definitely move the bulb into the lamp house before making a decision... All the diffusion heads I've seen have the light coming in horizontally and bouncing around the mixing chamber... You'll no doubt have longer exposures in that position, but you should get an idea of how even you can get... You should be able to unscrew the bulb bracket and flip it so the socket is facing horizontal. Good luck.

[Robert Oliver]

The bulb is horizontal in this configuration... Moving it to the other side of the filter holder into the lamp house should even up the light a bit. I just need to figure out a way to mount it in the lamp house.

[jbmia]

Apologies.. I just saw your pic of the bulb.. What I did was put the opal/diffusion material in the bottom of the lower condenser housing. I lined all sides of where the condensers normally go with styrofoam and replaced the mirror with that as well. Just something to consider. Looks like your putting your diffusion at the top of the top condenser.

Many manufacturers used styrofoam, but interestingly looking in the 6x9 mixing box of my other durst enlarger, it's lined with shiny metallic material instead of styrofoam.

[Luis-F-S]

[QUOTE=Robert
Tonight I did a couple of quick tests to see if I want to pursue an LED conversion. [/QUOTE]

I would use a 3400K bulb, not a daylight bulb. Also, do you have a reason not to use a G140 bulb? I think the coverage will be much more even. L