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  1. #21
    Steve Smith's Avatar
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    Quote Originally Posted by ic-racer View Post
    Ok, now that I see it, it looks like a good one for a LED project as that is not a common head. Nice that it incorporates a wall mount bracket on the chassis. Good luck, keep us posted.
    Here it is in my darkroom and fixed to the wall, waiting for its new light source. I had a day off work today - unfortunately the LED PCB is at work so it will have to wait until tomorrow. With me being the impatient type, I'm surprised I didn't go to get it.

    I think the PCB will fit in the removable top half of the head quite easily. I'm wondering if I should keep the strange water filled diffuser or put something else there. Does anyone know how much water should be in it? When it is level there is a 2" x 3" air pocket in the middle of the image area. I'm thinking it should be filled up a bit more to optically couple the front and back surfaces but I don't really know how it should be.

    I did put a 5x4 negative in, fitted my 105mm lens (I need to get a 135 or 150) and with a desk lamp held above I focused an image onto the baseboard (I told you I was impatient!).
    Attached Thumbnails Attached Thumbnails devere4.jpg  
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  2. #22
    Steve Smith's Avatar
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    I now have the LED PCB in place. I don't have any translucent material here to use as a diffuser so at the moment it is using three layers of kitchen roll. It diffuses well enough but restricts the output a bit. I didn't have any luck with its original water filled diffuser. There is still sufficient to make a print with and I would have done just that if I actually had some print developer!

    The picture attached shows the partially opened negative holder with red, green, blue and white settings. I'm not sure why my digi-thing rendered the green as cyan but in reality it is a really nice primary looking green. The blue is a lot deeper than shown here too.


    Steve.
    Attached Thumbnails Attached Thumbnails RGB.jpg  
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  3. #23
    ic-racer's Avatar
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    Lets see a picture of the LED PCB. Is there some kind of controller with it? Power supply?

  4. #24
    Steve Smith's Avatar
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    Some views of the PCB with LEDs off, red, green and blue on and just red on. The PCB has a common anode connection and red, green and blue cathode connections. I have a four wire cable going to a three gang, four position rotary switch which gives the options of red, green, blue or all three colours together. The PCB has current limit resistors so I just use a basic 30 volt DC power supply. each colour draws around 120mA.



    Steve.
    Attached Thumbnails Attached Thumbnails DSCF0391.JPG   DSCF0390.JPG   DSCF0392.JPG  
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  5. #25
    ic-racer's Avatar
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    Quote Originally Posted by Steve Smith View Post
    Some views of the PCB with LEDs off, red, green and blue on and just red on. The PCB has a common anode connection and red, green and blue cathode connections. I have a four wire cable going to a three gang, four position rotary switch which gives the options of red, green, blue or all three colours together. The PCB has current limit resistors so I just use a basic 30 volt DC power supply. each colour draws around 120mA.



    Steve.
    Ok, so that is from a LED stage light. Looks like a fantastic fit!
    I guess there would be a lot of ways to hook that up, from a very complex closed-loop, PMW system to simple toggle switches for the colors. What are your thoughts on the hookup?

    Just a guess here, but I'll bet it will give a better light distribution with a diffuser that is thicker in the center. The bottom plastic plate diffuser of a Chromega mixing box comes to mind.

    Also, I'm curious as to how the exposure times will be. I'm still skeptical about LED intensity.
    Quote from Wiki (not my own experience):
    A 300 watt medium-spot GE PAR-54 easily outshines a PAR-64 RGB LED Pro fixture from American DJ, which is one of the brightest LED fixtures available in 2008.

    Anyway, I'm pretty impressed! If this thing works, it will put Aristo out of business. (Oh, they already went under ).
    Last edited by ic-racer; 05-29-2010 at 11:17 AM. Click to view previous post history.

  6. #26
    Steve Smith's Avatar
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    The light is not as bright as a bulb would be and that Wiki quote is also correct - it is not as bright as a 300 watt stage light when in its original use as a PAR 64 light. However, I was very surprised at the light output of these stage lights when I first saw them. I didn't think anything would ever replace incandescent for stage use but for small stages in marquees, etc, they are very good.

    However, I didn't pay anything for it (it was a spare after I repaired another one for a sound company I occasionally work for) so I think it is well worth experimenting with.

    For graded papers I can either give separate blue and green exposures or even three exposures - blue and green together, then separate blue and green exposures or I could make a continuously variable PWM system with a single control going from 100% green, 0% blue through to 0% blue, 100% green.

    Whilst I like the idea of having a single 'contrast' control, this will effectively halve the output and increase printing time.

    The fit is perfect. There is a plastic plate behind it with four M5 bolts which fit in the cold light transformer mounting holes and also three M3 pillars which line up with some existing holes in the PCB.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  7. #27
    mhulsman's Avatar
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    I am also testing with a Par56 led .
    In the future I want to replace the light in my CLS 1840 head.
    A friend of mine had a broken Par56 led light with DMX control.
    It is an 153 leds system, with 5mm leds. 1850 lux /1m
    It is this one http://www.bax-shop.nl/led-par-56/ba...t-details.html
    Very cheap and has DMX control
    I tested the Par56 with my 10x10 lightbox but got uneven lighting.

    Than I removed my 100 box from the CLS1840 and hold between the lightbox and the Par56, lighting is now more even.


    The Pro with this head is the cost (less than 50 euro) and the possibility to control with DMX.
    With an USB DMX controller and some freeware DMX software you can program your densities.
    And for example lit for 5 seconds the red leds before the actual lighting, nice when doing dodging and burning.
    And this is only with 5mm leds, suppose you build your own system with 3W leds.
    This is not something I want next week, I will continue printing with my CLS 1840 and ignore the noisy fan that run about 3 minutes when you even expose for 0.1 second
    --Mike

  8. #28
    Rick A's Avatar
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    Quote Originally Posted by Steve Smith View Post
    Here it is in my darkroom and fixed to the wall, waiting for its new light source. I had a day off work today - unfortunately the LED PCB is at work so it will have to wait until tomorrow. With me being the impatient type, I'm surprised I didn't go to get it.

    I think the PCB will fit in the removable top half of the head quite easily. I'm wondering if I should keep the strange water filled diffuser or put something else there. Does anyone know how much water should be in it? When it is level there is a 2" x 3" air pocket in the middle of the image area. I'm thinking it should be filled up a bit more to optically couple the front and back surfaces but I don't really know how it should be.

    I did put a 5x4 negative in, fitted my 105mm lens (I need to get a 135 or 150) and with a desk lamp held above I focused an image onto the baseboard (I told you I was impatient!).
    Have you found a lens for it yet? I have an old Liesegang, Dusseldorf - Parastigmat 135mm enlarging lens. I'm not sure of the mount size, but it does have an adapter flange that it screws into. You can have for the price of postage from the USA.
    Rick A
    Argentum aevum

  9. #29
    ic-racer's Avatar
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    Quote Originally Posted by mhulsman View Post
    This is not something I want next week, I will continue printing with my CLS 1840 and ignore the noisy fan that run about 3 minutes when you even expose for 0.1 second
    Which power supply? EST1000N? I know that some of the power supplies (like my EST2000N) only 'overrun' the fan if the temp in the housing goes above ambient temp. So, my fans shut off as soon as the lamp goes off. It only stays on if I run a bunch of exposures right after another, then it stays on until its cool up there again.

    That LED conversion looks promising, but I would imagine that the heat from 1000watts of LED (if you could ever get that much) would still require the fans

  10. #30

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    Thats cool that you got a 4X5 enlarger. I recently bought a Crown Graphic camera and an Omega DII Enlarger. The enlarger was $75. It has a Bausch and Lomb f4.5 139mm lens. The problem was the lens was frozen at f11. The fix required some carburetor cleaner and a large pair of pliers. f-stop ring is very smooth now.

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