LED Light Panel for 11x14 Enlarger?

[John Layton]

I’m getting my 11x14 camera back into shape, and will also be cobbling together enough of an 11x14 horizontal enlarger to test the viability of pressing my 305mm G-Claron into service as an enlarging lens for this format.

If all goes well on the testing front…my plan would then be to further refine the enlarger, and to seek out a light source - oversized to accommodate the spread of light through the wide angle (for this format) 305mm lens. So I’m figuring something in the vicinity of 14x16 or 16x16 should do the trick.

While I’d love to think that I could find an RGB LED flat-panel light which would be both bright enough and offer a good range of green to blue wavelengths (to allow for split-grade printing), my guess is that I might need to settle, at best, for a “white light” (about 5600K) lamp, and incorporate a slot for placing colored gels between this lamp and the negative stage. I’m also guessing I might need a bit of diffusion material to help smooth things out a bit.

At any rate…might the above quest for such a light source be a “pipe dream” respective of what I might require to make enlargements from such (11x14) negatives up to sizes in the vicinity of 40x60 inches?

Here is an example (16x18 RGB Flat Panel) of what I’m guessing (hoping!) might work:
https://www.bhphotovideo.com/c/produ...led_light.html

Alternately, I do see that Glennview lists a 16x16 “high energy blue” florescent lamp, which I’d imaging might fit my needs given that I could filter this adequately. Even better might be to simply locate an Aristo 1414 florescent lamp (which apparently measures somewhat larger than 14x14 so my guess is that it would work), but I cannot currently find any of these available for sale.

Finally, while I truly love and depend upon my Heiland LED-VC lamp for 5x7 and smaller negatives, there is simply no way I could currently afford a version of this lamp large enough to accommodate 11x14 negatives.

At any rate…I’d truly appreciate any amount of information, enlightenment, “what are you thinking?” commentary, etc. - to help me on my quest. Thanks!

[Tin Can]

Posted my experiments at least a decade ago in DIY

11X14 easy

but it is a moving target as lamps evolve

[monochromeFan]

beyond my skill level, but have looked into it before. Many of the DIY articles i came across last year mentioned the use of those large ilford contrast filters as being mandatory.

One could use it as a contact printer.

I remember one person making diffusion panels by taking old LCD tvs apart for the component diffusion panel they use on the outer layer.

[phdgent]

Ever thought about the ROSCO LitePad? These come in different shapes and measures and CCT95.
Their light colour output can be controlled and dimmed.
ROSCO has other LED products and controlling systems too (I am not affiliated to ROSCO).

[Alan Townsend]

John,

I would DIY a panel using warm white LED strips, which are closer in color to tungsten lamps that those filters are designed for, then use VC filters that fit below the enlarging lens. All you need are grades 0 and 5, or whatever the limits for your paper require, then use split grade printing to get the values in between. I recently put a single warm white LED bulb in my 35 mm enlarger and it worked OK with the above the lens set I already had. You can use translucent white plastic sheets for diffusing the LED strips.

Alan Townsend

[John Layton]

Alan, I like your idea of using the warm white LED's with filtration...but I would use large gels which I would slide into a dedicated slot cut just in front of the light source. There are two reasons for this...one being that I did a test a few years back - very carefully bringing a negative into focus on the easel plane, then did the same (careful focussing) thing with a below the lens filter, and an above the lens gel. The below the lens filter result was visibly less sharp (as least through the focus magnifier) than was the above the lens filter result. The second reason is that I remain leery of removing then replacing below the lens filters during a single print exposure scenario...as if I'm not careful I might alter the aperture setting slightly, or if the second filter has any significant thickness and does not fall exactly into the optical plane as the first, and/or if the filters themselves are not perfectly consistent with each other as per how well/accurately they are factory mounted, then this amount of displacement might cause some unsharpness...due to the presence of a refractive index in combination with such relative movement.

Also, I find a negative stage to be generally more impervious to movements than I do a lens stage (and messing near or with the lens)

I hate to sound so nitpicky about all this!

[vinny]

The panel you linked to should work. I haven't used that particular product but I have used plenty of other Godox lights. They're decent for the price compared to LitePanels, Arri, or others. Keep in mind that these fixtures typically aren't instant on like a tungsten light source. They take a couple seconds to power up. Building in a slot for split grade filtration may be easier than trying to adjust the source while having paper on the easel. It can be controlled with an app, but again, that screen will illuminate the darkroom.
I'd stay away from the Rosco product someone else suggested. That's pretty old technology and they were pretty poor units which had to be color corrected due the the magenta/green spikes plagued by typical led sources.

[Peter De Smidt]

The Godox light looks pretty good. I have some Godox flashes, and they've worked find for me. With any light like that, you'll have to make sure the individual dots are obscured. Personally, I think that dealing with big filters would be a huge pain.

Another option: Use am LED monolight and bounce it off angled foamcore/styrofoam.

[John Layton]

Thanks everyone!

While I'll still be researching possible light sources...my next task will be to cobble together an enlarger mockup, likely using an array of my gallery lights behind a glass/negative sandwich - to test the efficacy of using my 305 G-Claron for enlarging, thinking that my available space for this setup might not allow me to use a focal length much longer than this...especially seeing as my ultimate goal is to create prints up to 40x60 inches.

If things look good, then I'll likely go ahead and spring for an existing LED light panel so I can design this into the actual enlarger. Fingers crossed!

[Peter De Smidt]

That's going to require a lot of light!