Help, Ilford, my enlargers is not well.

Kilgallb said:

it had a measured colour temperature of 3200K

Click to expand...

Looking forward to hear your results. Chosing a good LED for the enlarger is rather tricky. There are problems with uniformity, the spectrum, possible UV emissions, ...

Have you seen the spectrum from the data sheet of the LED? Is it continuous or only small peaks in RGB?

RauschenOderKorn said:

Looking forward to hear your results. Chosing a good LED for the enlarger is rather tricky. There are problems with uniformity, the spectrum, possible UV emissions, ...

Have you seen the spectrum from the data sheet of the LED? Is it continuous or only small peaks in RGB?

Click to expand...

I have no data sheets at all for the LEDs, just a quick measurement last night with a minolta CL-200 meter I borrowed from work. I will have more time tonight to make careful measurements. You are correct though, most LEDs will not have a smooth fill of the spectrum but instead have high intensity at specific wavelengths.

I just finished measuring up the system. I also compared it to my Omega D2 condensor enlarger

Omega: Maximum variation in light over a 20x24 image: +11% greater than average, -8% dimmer than average. This was at f16.
Converted Beseler: Maximum variation in light over a 20x24 image: +12.5% greater than average, -22% dimmer than average. At f5.6 the variation was 50%

I checked colour temperature:
Omega: 2900 K
Converted Beseler: 2880K

Beseler with LED
With Ilford 00 filter u'= .3096 v'= .5411
With Ilford 5 filter u'= .3796 v'= .5160

Omega
With Ilford 00 filter u'= .3096 v'= .5438
With Ilford 5 filter u'= .3942 v'= .5169

I think uniformity is ok (less than 1/4 stop variation) but I might have an issue with the grade 5 filter. I will try some split grade printing tomorrow.

I have attached pictures of the mod and parts. I removed the ring on the bottom of the Beseler 45 Dichroic boxx, the part that mates with the enlarger. I removed the lid frm the mix chamber and mounted the lamp on top. So I am still using the beseler diffuser. Total cost so far is $30 Canadian for the lamp. I will invest a bit more to make it a permanent installation.

.

Color temp meters can get fooled by discontinuous spectrum sources like this, so ultimately, it will be actual split printed paper tests that count.

Kilgallb said:

I tried to contact modern enlarger lamps but the web site appears offline.

Click to expand...

I purchased a Model 2 from Modern Enlarger Lamps earlier this year. I've noticed that the site frequently goes down. The owner, Cemil, took a number of days to get back to me after my initial email, but I did eventually get my order in. It arrived about a month later. It wasn't a fast process, but overall I'm pleased with the product.

DREW WILEY said:

Color temp meters can get fooled by discontinuous spectrum sources like this, so ultimately, it will be actual split printed paper tests that count.

Click to expand...

Ghetto color temp test - shoot a raw still with a decent DSLR. In camera raw, you get a histogram and temp and tint sliders. Unless there are some very bizarre spikes (like the early days of CFLs with their hit of green) you can check the temperature (blue-orange axis) and the tint (green/magenta axis). When I get a new daylight source (say an LED or HMI) I can see if it has any quirks.

I use this to dial in gel combos to get my lights to match location lights. Works really well, when I scout I shoot a gray card around the office or whatever location and check those shots in camera raw. (So I can match my lights to the location but still use the existing lights for fill, and use my flos or HMIs for keys).

I am not sure how to interpret your numbers.

Kilgallb said:

Beseler with LED
With Ilford 00 filter u'= .3096 v'= .5411
With Ilford 5 filter u'= .3796 v'= .5160

Omega
With Ilford 00 filter u'= .3096 v'= .5438
With Ilford 5 filter u'= .3942 v'= .5169

Click to expand...

What do these mean?

With regards to the contrast you are getting with the new light source, your testing has made me rather curious and I tested my enlargers, too. Giving it some thought, I would think that the projection size does not matter, while the lens and the negative mask used do have an important effect.

For both my Dunco 6x7 and the Omega D5 Super Chromega I am getting a contrast of around 0,15 logD focused, at open aperture and largest negative size possible (i.e. 6x7 cms for the Dunco - Componon 4/80 - and 9,5x11,5 cms with the Omega - Rodagon 5,6/135), i.e. around 30% variation in the intensity of the illumination. Stopping down the lens to smallest aperture or masking (using a 6x9 cm mask in the Dunco), the contrast is reduced to values between 0,02 logD and 0,05 logD, i.e. less than 10% variation and values which my equipment cannot measure any more with sufficient accuracy. As stopping down greatly reduces the contrast and the values are distributed accordingly, I have measured the vignetting of my lenses.

How did your split grade printing work out?

My split grade printing was good news and bad news.

I managed to get a great print but it appears that exposure on grade 5 is about three stops greater than grade 00.

I printed a known negative and found the ratio of exposure on grade 5 to grade 00 was almost 10:1 more than with a tungsten lamp.

It is workable but a pain. Either long exposures on grade 5 and short on 00. I am worried I will not get the usual control.

I hope the modern enlarger lamp site comes on line again. I am ready to take the step to get that product.

In the mean time at least I can be printing again. Time to save my pennies.

Does anyone know the email or phone number for modern enlarger lamps? Maybe he will respond to a direct inquiry.

Kilgallb said:

Does anyone know the email or phone number for modern enlarger lamps? Maybe he will respond to a direct inquiry.

Click to expand...

Try modernenlargerlamps@icloud.com