2013 5X7 Enlarger LED Experiment Parts

[Tin Can]

https://live.staticflickr.com/65535/51497331235_ea547eb028_c.jpg (https://www.flickr.com/gp/tincancollege/39J8Fo)5X7 Enlarger Head Test 2013 (https://www.flickr.com/gp/tincancollege/39J8Fo) by TIN CAN COLLEGE (https://www.flickr.com/photos/tincancollege/), on Flickr

[Ulophot]

Well, this is really interesting! Is this the LED unit you mentioned in a post yesterday? I believe you said that the light was, if anything, too bright.

Anyway, I just measured my venerable Omega D2, after seeing that the 9x6 model of the same Art-O-Graph LitePad measures 11.25" W x 8.5" D x .5" H. The 8.5-inch depth, with the unit centered, would clear the focusing rails behind the lens stage. The length simply means masking, and the half-inch thickness could be fairly easily dealt with. In principle, the unit could simply be adapted to be fit onto the bottom of the aluminum collar that now holds my cold light head (or could be condensers in someone else's machine). At about $120, it's very enticing! -- but there is at least one further issue:

Those matters of design accomplished, the main issue would be the on-off function, which could be a deal-breaker for me, since I use Fred Picker's intervalic exposure procedure, e.g., ten 3.4-second exposures, rather than one longer one. Quick and consistent on-off would be essential.

After all my hopeful imaginings regarding a simple LED light source for enlarging, I expect rain to call on this parade as well, brought by those who know infinitely more about electronics and engineering than I (which doesn't require much).

Do you have anything to add from your experience with your experiment?

[Tin Can]

I doubt my experiments match your expectations

It was just a test, I moved on, I republish to support experimentation

Then I tried a 2013 600 LED Studio Lamp I still use in studio, took this pic minutes ago

This is the one that needs to be powered down 90% by factory included PVM and masked off everywhere, I put a dark cloth over it all to contain light leaks, low heat, the power adapter does get hot, but at 3 ft distance and safe

I am still experimenting, as I just resumed the scrum

the solution is out there

https://live.staticflickr.com/65535/51676703858_c43cbec674_z.jpg (https://flic.kr/p/2mJuBEJ)600 LED Studio Lamp (https://flic.kr/p/2mJuBEJ) by TIN CAN COLLEGE (https://www.flickr.com/photos/tincancollege/), on Flickr

[Michael R]

Why wouldn’t the enlarging/exposure timer take care of that part?


Well, this is really interesting! Is this the LED unit you mentioned in a post yesterday? I believe you said that the light was, if anything, too bright.

Anyway, I just measured my venerable Omega D2, after seeing that the 9x6 model of the same Art-O-Graph LitePad measures 11.25" W x 8.5" D x .5" H. The 8.5-inch depth, with the unit centered, would clear the focusing rails behind the lens stage. The length simply means masking, and the half-inch thickness could be fairly easily dealt with. In principle, the unit could simply be adapted to be fit onto the bottom of the aluminum collar that now holds my cold light head (or could be condensers in someone else's machine). At about $120, it's very enticing! -- but there is at least one further issue:

Those matters of design accomplished, the main issue would be the on-off function, which could be a deal-breaker for me, since I use Fred Picker's intervalic exposure procedure, e.g., ten 3.4-second exposures, rather than one longer one. Quick and consistent on-off would be essential.

After all my hopeful imaginings regarding a simple LED light source for enlarging, I expect rain to call on this parade as well, brought by those who know infinitely more about electronics and engineering than I (which doesn't require much).

Do you have anything to add from your experience with your experiment?

[Tin Can]

I may now try a LED point source with CB7 condensers

A CB7 is just a bit smaller than a 5X7 head as it has a BIGGER Hole

I have a very old CB7 which has a square light panel on top of condensers

Last time I wrote about that, nobody knew of that AGFA head

[koraks]

Why wouldn’t the enlarging/exposure timer take care of that part?

Not all led power supplies are created equal, sadly (or perhaps fortunately - they might all have been junk in this respect).
Case in point: I purchased a led strip + fitting power supply the other day for interior decorating, so no critical timing requirements. The power supply is a simple SMPS. I turn it on by simply applying grid power to it; it's connected to a switched wall outlet. It takes between 1 and 3 seconds to actually turn on the led as soon as power is applied, with the delay being somewhat random. It's OK for the light accent on our new wardrobe, but utter crap for an enlarger of course.

Morale of the story: you gotta try it to see if it works. No guarantees whatsoever. Chinese electrons sometimes move slowly, it seems.

[Michael R]

Interesting. I guess it makes sense many of these are junk.


Not all led power supplies are created equal, sadly (or perhaps fortunately - they might all have been junk in this respect).
Case in point: I purchased a led strip + fitting power supply the other day for interior decorating, so no critical timing requirements. The power supply is a simple SMPS. I turn it on by simply applying grid power to it; it's connected to a switched wall outlet. It takes between 1 and 3 seconds to actually turn on the led as soon as power is applied, with the delay being somewhat random. It's OK for the light accent on our new wardrobe, but utter crap for an enlarger of course.

Morale of the story: you gotta try it to see if it works. No guarantees whatsoever. Chinese electrons sometimes move slowly, it seems.

[Tin Can]

I had trouble with ancient DR timers

I assume there was not enough load for them to start, as they worked with incandescent

No idea what I used then

However I bought many 'used and working' timers from members I also forgot

junk

[Ulophot]

For whatever it may be worth, I have what I consider the luxury to have a Zone VI timer, which includes 0.1-sec increments along with 1- and 10-second ones; a dimmer; volume control on the beeper, an adjustable minus percentage for dry-down compensation, and a light-output compensation circuit that works with my coldlight. The only thing in might have but doesn't, is a plug for the safelight, so that the safelight goes out when the time goes on, as the TIme-O-Lights do. Not a problem for me. My understanding is that power adapter for LEDs typically regulate the current so that the line voltage variations my compensating time now takes care of are no longer an issue.

Philip "Remaining the Optimist for a Solution" U.