LED Light Panel for 11x14 Enlarger?

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!

Posted my experiments at least a decade ago in DIY

11X14 easy

but it is a moving target as lamps evolve

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.

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).

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

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!

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.

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.

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!

That's going to require a lot of light!

Lots of light...yes indeed! My gut tells me that I'll ultimately need to seek out some top-tier LED's of very narrow/specific (RGB) wavelengths and cobble something together myself...attempting to emulate my super efficient 5x7 Heiland LED/VC head (which I still sometimes need to "power down" while printing 40x60's!).

On the other hand, I do also need to be open to the possibility that I will fall in love, once again...with 11x14 contact prints. And oh my goodness...would that ever solve so many issues! But still...I've got this enlarging itch (enlarging enlarging itch?) that I just need to scratch!

Remember Ansel's 8x10 enlarger, the one with a grid of the halogen bulbs? I'd try something similar, but I'd use high cri LED Cob fixtures, possibly RGB, depending on lumen output. Maybe use a lux meter to meter how much light your enlarger puts at at a normal sized enlargement, and then do a test with one of the leds.....Actually, I could probably do that for you, but I'd be limited to 8x10. When you get closer, and if it'd help, remind me. I have a couple of mid-level COB lights. What aperture would you be using your g-claron at? F11? I just built a light box for digital camera scanning using one of the panels, but the lumen output is no where near what you'd need.

We forgot Lina!

11x15!

https://www.youtube.com/watch?v=ijpD_O70tuA

Yes I do

I have a bigger one

Saltzman mounts 25 Edison sockets with heavy wiring

Round pattern 25” sg

Ifs in my catalogue

Mr. Can yes I've thought about something similar. In fact, I believe that Uncle Ansel used a multi-edison bulb array for quite some time - and, obviously, quite successfully!

...or how about this - to realize the maximum efficiency of an LED light panel, I either purchase or create three of them, one just green, one just blue, and one just white. I could have a slot at the rear of my DIY'd horizontal enlarger to allow quick yet stable insertion/removal of these panels as needed for focus (white panel), then testing, and then split grade printing (green and blue panels).

In fact, with a bit of creative and light-proof cowling, I could construct a "panel box" with its own slot, and have this isolated (contact and vibration-wise) from the enlarger by using a blackout cloth cowling to connect box to enlarger, mitigating potential movement of the enlarger during the panel changes.

I might also be able to incorporate an electrical switch mechanism so that there would be just one connecting plug for the timer for all three panels - so I would not need to remove and re-plug during the process.

Sound like a plan?

I am recalling my 2013 plot

I covered LED panel wit dark cloth

Not all timers worked

The timer on lagged



More asi remember

I bought many smaller one light panels

I made ULF enlarges positives' as gifts to my Doctor

I also used X-Ray to makes stained glass

I bought a Saltzman neg stretcher which I used as "Head'




https://www.amazon.com/dp/B01JJOEK4O...1zcF9kZXRhaWwy

Mr. Can you remind me, that with respect to my "three separate light panels" post above, and that there may indeed be a slight lag in stable brightness (especially as these panels will likely be DIY) - that I will be using my (shutter-mounted) 305mm G-Claron as an enlarging lens, and will be sure to make good use of its shutter to begin timed exposures only after such stability is achieved.

What happens with LEDs is that they get brighter up to a certain temp. As they go above the temperature, they get a bit dimmer. I usually run mine a bit lower than maximum brightness.

I had an Aristo 1414 head, though, only used if for 8x10.
I made custom filters by attaching Roscoe sheets to clear polycarbonate. These durable filters slid in to a filter slot, just above the diffuser. Much easer than sliding in a whole light panel.

It looks like you are doing color, but if you were doing B&W, only two filters are needed. I used Green and Blue, but there are other combinations out there.

Attachment 245795
Attachment 245796

I'm doing just black and white...and based on my experience with my 5x7 Heiland LED VC head, I've come to like the white light for focussing. While a mix of green and blue can work for this (focussing) purpose...I find it more difficult to focus using only green or blue light, but I could probably get used to this - especially if I could upgrade my focussing magnifier to something like a Peak-I.

Questions about your using an Aristo 1414 with Roscoe sheets: What were typically the size of your larger finished prints, and what ranges of exposure times and aperture values might also be typical for your setup?

My questions stem from my concern that, keeping in mind that I'm enlarging 11x14 negatives and that I'd plan to print as large as 40x60, that using an essentially white, florescent light source and using filters over this might cut the final light output to levels which would be too low to be practical - also seeing as I'd want to be using my 305 G-Claron stopped down to at least F/16 or even F/22...for depth purposes to help mitigate inaccuracies of focus, but also assuming that, like the 150 G-Claron I use for printing from 5x7 negatives (vertically to 30x40...the 180 Companon-S works better for 40x60), its "optimized" aperture value would actually be f/22 for this use.

Then again, the Heiland can almost be too "bright" at times as its LED's are so very efficient - wavelength wise, and I sometimes need to power them down even when printing to 40x60...just to keep my exposure times reasonably long to allow for often complicated dodging/burning scenarios - so perhaps something like a 1414 would work?

Remember also that 8x10 negatives projected to 8x10 paper will be 1:1 so there will be a 2-stop bellows factor; enlarging to something like 16x20 will still probably be 1 stop which is why those large format enlargers often had 1000W light bulbs in them. I don't see that a consumer-grade light panel will have anywhere near the output to be useful.

Vaughn...yes, I'm gathering that consumer-grade light panels probably won't cut it - especially as I'm enlarging 11x14 negatives to sizes as large as 40x60.

This is why I'm actually thinking that I'd be best served by separate LED light panels (one green and one blue, and perhaps a white panel for focussing) so that I can realize maximum efficiency from each color.

These panels could slide into a housing behind the enlarger - isolated from the enlarger by means of a black cloth cowling to mitigate the potential for upsetting the (absolutely critical) placement of the negative within its glass sandwich.

I don't think light panels will cut it, unless they're of the professional cine type. My 810H De Vere (a horizontal mural enlarger) had a 2000w head. My guess is it'll take a matrix of COB fixtures.

Maybe an oversized light mixing box - 4 panels (RGB if you want) side-firing, which also theoretically eliminates the diffuser stage. I used this principle in constructing the light source for my sensitometer. Of course that’s just a small box and it is only on for short periods of time, but it is extremely powerful. Whether or not this would scale up to that huge size is an open question. You’d definitely need a way to dissipate heat.

Anyway just an idea.

Attachment 245800

Thinking about the extreme efficiency of my Heiland 5x7 VC LED head - which is RGB no less...makes me think that three panels, each with a single color of the "correct" LED's at a high density, just might do the trick.

I'd obviously need to find the "correct," most efficient (green, blue, and perhaps white) LED's for this project, and would certainly be open to suggestions, from the number of folks here who've either DIY'd an LED enlarger light or who are in the process of doing so...and who thus have far more experience than I.

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I'm doing just black and white...and based on my experience with my 5x7 Heiland LED VC head, I've come to like the white light for focussing.

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Of course, did not think about that.

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Questions about your using an Aristo 1414 with Roscoe sheets: What were typically the size of your larger finished prints, and what ranges of exposure times and aperture values might also be typical for your setup?

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With the Aristo 1414, I always had a yellow Roscoe sheet in place, due to the older style lamp (my receipt for the Aristo 1414 was dated 1988). Also, maybe due to the lamp's age, I needed a center filter to even out the hot spot.

Then I had the color filters, which were somewhat dense primary colors from Roscoe.

The times were not too bad, but, at the time, I only had trays for up to 16x20 prints (2x enlargements).

One issue that reared its ugly head was the need to always keep the filter order the same. Why? As the lamp is on it's light intensity dimininished.

For example if the shorter blue exposure were first on the test print, but the longer green exposure was used first on the final print, the heating of the lamp for the longer exposure would affect the print and it would not be exactly like the test print.

When I sold the 1414, in spite of bubble packing it into a 30"x30" box, the lamp broke. Maybe a blessing in disguise, as Aristo/Voltarc made a new lamp ($500/2017) with the proper color to work with multigrade filters. Maybe the new lamp had better thermal qualities and no hot spot either, as the new owner never complained about it.

The graph was constructed with the termostat set to 40C.

Attachment 245804

I used a Salzman 5X7 Film Stretcher

With custom tunnel holder for it


I put the Lamp as close as possible to negative
I found my LED high end Panel had be to turned down 90%

I THINK I used my Variactor

How big of a print where you making, Randy?

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Originally Posted by Peter De Smidt

How big of a print where you making, Randy?

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as big as my FOTAR Baseboard, 40X60"

6 sheets 14X16-XRay for my south windows inside my double steel doors

I was testing fade and stained glass effect

I've built / rebuilt a DIY LED 5x7 head for my Durst several times now.
First was with standard RGB LED Strip lights - worked as proof of concept, but the Blue isn't the right wavelength for VC papers - gave about a grade 3 1/2.

I updated several years ago to add 'Pink' LEDs instead of Blue from the RGB set. Everyone is going to say I'm wrong and need to use Deep/Royal Blue, but after much research (and confirmation with a spectroscope) the 'Pink' LEDs I have are really a deep blue LED emmitter with an additional phosphor coat that fluoresces, adding wavelengths making it pink. Deep Blue by itself is terribly hard to see in the dark - the added waves just makes it much easier to see - much like the Ilford MG #5 filter is pink. Easily gives me grade 5 as shown by step wedge. The bottom set is pure pink LED, the one above is Ilford #5 through white light.

I recently rebuilt the head but got rid of the RGB + pink, and updated to individual strips - Green, Pink and White (though the Green + pink together produces a pretty convincing white).

The newest COB strip lights are amazingly bright. For the attached image they are turned down to about 5% output. For a 4x enlargment I run them about 50% with times in the 15-30 sec or so.

I found a 3 channel LED controller/dimmer with digital display from one of the online LED shops, along with a custom relay controller I built for using with my standard darkroom timers, eliminating the time delay LED can have.

It has been working great. Getting the right diffusion and evenness can be tricky but very doable. I have not noticed any banding in enlargements or contact prints.
Attachment 245834Attachment 245835Attachment 245836

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Originally Posted by Tin Can

as big as my FOTAR Baseboard, 40X60"

6 sheets 14X16-XRay for my south windows inside my double steel doors

I was testing fade and stained glass effect

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That's great! I'd be glad to be wrong about how much light is needed.

I built a 5x7 with 12 green and 12 royal blue high power LEDs. It could easily be scaled up to 11x14 with 4x the number of LEDs. 40x60 should be doable with reasonable exposure times.

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Originally Posted by malexand

I've built / rebuilt a DIY LED 5x7 head for my Durst several times now.
First was with standard RGB LED Strip lights - worked as proof of concept, but the Blue isn't the right wavelength for VC papers - gave about a grade 3 1/2.

I updated several years ago to add 'Pink' LEDs instead of Blue from the RGB set. Everyone is going to say I'm wrong and need to use Deep/Royal Blue, but after much research (and confirmation with a spectroscope) the 'Pink' LEDs I have are really a deep blue LED emmitter with an additional phosphor coat that fluoresces, adding wavelengths making it pink. Deep Blue by itself is terribly hard to see in the dark - the added waves just makes it much easier to see - much like the Ilford MG #5 filter is pink. Easily gives me grade 5 as shown by step wedge. The bottom set is pure pink LED, the one above is Ilford #5 through white light.

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Can you point me to the details of the pink LEDs you are using? They sound interesting and not something I would have thought of.

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Originally Posted by Larry Gebhardt

Can you point me to the details of the pink LEDs you are using? They sound interesting and not something I would have thought of.

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The item I ultimately got most recently was https://www.amazon.com/gp/product/B09MRK3CHC
When I was first looking at them several years ago, one of the LED retailers has posted the spectrum graphs of all the options, but either I remember the wrong site, or they stopped publishing that info. They matched closely to that of the curve of the High contrast layer of Multigrade.
I used a spectroscope myself on both the Royal Blue and the Pink, and the peak in the Blue was exactly the same. In fact, if I bring the lit Royal Blue LEDs close to the unlit Pink, the pink will glow brightly from the phosphors.

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Originally Posted by malexand

The item I ultimately got most recently was https://www.amazon.com/gp/product/B09MRK3CHC
When I was first looking at them several years ago, one of the LED retailers has posted the spectrum graphs of all the options, but either I remember the wrong site, or they stopped publishing that info. They matched closely to that of the curve of the High contrast layer of Multigrade.
I used a spectroscope myself on both the Royal Blue and the Pink, and the peak in the Blue was exactly the same. In fact, if I bring the lit Royal Blue LEDs close to the unlit Pink, the pink will glow brightly from the phosphors.

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Interesting. I can definitely see the advantage of being able to see the projected image when using a high grade for a negative. I was considering using red LEDs to address that issue in my next iteration of the head. Do you think a lot of the blue wavelength intensity is lost as it interacts with the phosphors? In other words what are the exposure times compared to the same LEDs without the phosphors?

If you want to go the DIY route, lot's of people have built similar light sources to what Larry talks about for reef aquariums.

My experience with the Heiland's blue light is that its almost too efficient...so I'd not worry too much about a bit of pink getting in the way if that's what's likely to happen.

...and Larry - thanks for your encouraging words about "scaling up" (from 5x7)...gives me a bit of hope!

I do have another concern about making big (30x40, 40x60 inch) enlargements from 11x14 - which is that I might be quickly reaching a point of diminishing returns (compared to smaller format enlarging) as I will tend to be very close to the "cliff of diffraction," and I may need to change my tune and set my aperture values for somewhat larger openings when compared to those for contact prints...which also means extra care in focussing and courting the likelihood of occasional negative movements/displacements just prior to (or during!) making an exposure.

I've actually been thinking that I might occasionally make pairs of certain images, with one being set back a bit, aperture-wise, for "best compromise for enlarging," and a second a bit more stopped down for contact printing.

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Originally Posted by Larry Gebhardt

Interesting. I can definitely see the advantage of being able to see the projected image when using a high grade for a negative. I was considering using red LEDs to address that issue in my next iteration of the head. Do you think a lot of the blue wavelength intensity is lost as it interacts with the phosphors? In other words what are the exposure times compared to the same LEDs without the phosphors?

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I haven't done any exposure testing of the Royal blue vs Pink. If any is lost, I haven't noticed in use. With this latest build I'm getting similar times with the Green vs Pink channel. a typical 5x7 neg enlarged to 11x14 at f/8 is in the 10-20 sec range on a single channel.

BTW - Thanks for documenting your Durst 138 LED build years ago - I recall referring to your site several time when working on mine - a salvaged S-45 Special missing condensers.