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Old 8th March 2019, 12:22 PM
Terry S Terry S is offline
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Default Using LED lights in your enlarger

I am starting this new thread about this question rather than carry on taking another post in a totally different direction from its original title. This post can be found here:

http://www.film-and-darkroom-user.or...t=12357&page=3

So, after reading about using an LED light in ones enlarger, I thought it worthwhile to get one as a backup for mine, as the light bulb in it is from buying the enlarger new over 25+ years ago! And as we know old style bulbs are getting harder and harder to get hole of.

After reading the above post, I went to my very local B+Q yesterday and bought one of their own branded 'Diall' WARM white light 2700k LED bulbs, with an equivalent output of 75 watts = actually being 9.2 watts / 1055 lumens. So far so good.

I have yet to get to the darkroom to test it out, but one thing worries me.

One the back of the packet, there is among many little icons, one that says that the light will give out 60% of its full power in less than one second. This may not matter in general household lighting, but what about for enlarger use?

I am particularly worried as I use one of the 'RH designs' exposure timers and when doing a test strip, some of the exposures can be just over one second at a time. Using this bulb, I would therefore presume that I will not be getting the full exposure each time (whatever exposure is done on the test strip). But then, when doing a full exposure it would give a different total of time when compared to the test strip. (I hope this all makes sense?)

E.g. if I was making a test strip of say 2.0 seconds each to make it easy (but really with only 60% of the light in the first second) say 1.6 seconds (=only 60% in the first second).

Using the above as five separate exposures = the timer will say 2 seconds each time x 5 exposures, which SHOULD equal 10 seconds in total, but the individual exposures on the test strip will only total 1.6s x 5 = a total of 8 seconds!

Am I reading too much into this or can anyone correct me?

The only way I will really find out I suppose is by using it, but until then can anyone chip in?

Many thanks,

Terry S
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Old 8th March 2019, 12:51 PM
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Barry Barry is offline
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Hi Terry,

You don't say if your enlarger head is a condenser type using an incandescent bulb or if it is a colour head? I am using a condenser head successfully with this lamp.
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Last edited by Barry; 8th March 2019 at 12:58 PM.
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Old 8th March 2019, 12:56 PM
Terry S Terry S is offline
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Sorry Barry = good point!

Currently I have a b/w condenser enlarger with a screw in / E27 75 watt bulb, which is white (paint?) coated and I use Ilford MG filters under the lens.

And as previously mentioned I have bought, to try out, a B+Q (a British DIY store) own branded 'Diall' WARM 2700k LED bulb, with an equivalent output of 75 watts = actually being 9.2 watts.

Terry S
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Old 8th March 2019, 01:01 PM
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Hi Terry, we posted at the same time! I have edited my post to include a link to the led bulb I am currently using. It replaced a 150w Philips incandescent lamp. The only thing I have not tried so far is if it has acceptable times at grade 5. I use Ilford above lens filters.
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Old 8th March 2019, 01:54 PM
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Although I have just got around to putting led light bulbs throughout my house, I still haven't found the need to use them in the darkroom.

That being said, personally I wouldn't worry too much but then my aim for 8x10" exposures is to be around the 16sec mark. Based on a diffuser enlarger and a lens of longer focal length than the film format.
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Old 8th March 2019, 02:37 PM
Alan Clark Alan Clark is offline
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Terry, if you have a hand-held exposure meter, try taking a reading off the paper easel as soon as the enlarger light is switched on (with no negative in place) Then take further readings every 10 seconds. This should show you what you need to know.
In the other thread I did suggest going to an electrical shop and seeking specialist advice. When I got mine I did ask for a bulb that instantly came on at full strength. And on the package, which I have kept, it does say "Instant full light". and my bulb is rated 11W (equivalent 75W) My bulb cost £4.95. I don't know how much you paid, but B&Q isn't noted for being cheap.
I think £4.95 is cheap for a bulb that has turned out to be a perfect replacement for the old hard to get incandescent bulb. And, as it is rated at 15,000 hours, it will probably see me out...

Alan
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Old 8th March 2019, 02:42 PM
Alan Clark Alan Clark is offline
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Quote:
Originally Posted by MartyNL View Post
Although I have just got around to putting led light bulbs throughout my house, I still haven't found the need to use them in the darkroom.

That being said, personally I wouldn't worry too much but then my aim for 8x10" exposures is to be around the 16sec mark. Based on a diffuser enlarger and a lens of longer focal length than the film format.
Marty, you seem to be suggesting that LEDs are brighter and you don't need the extra brightness. But when the bulb you have in your enlarger is no longer made or very hard to get, then an LED bulb may be your only option.

Alan
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Old 8th March 2019, 03:09 PM
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Quote:
Originally Posted by Alan Clark View Post
Marty, you seem to be suggesting that LEDs are brighter and you don't need the extra brightness. But when the bulb you have in your enlarger is no longer made or very hard to get, then an LED bulb may be your only option.

Alan

Sorry Alan, what I was getting at is that I'd prefer to avoid having such short exposures and thus effectively eliminating the problem.
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Old 8th March 2019, 03:19 PM
Richard Gould Richard Gould is offline
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Quote:
Originally Posted by Terry S View Post
Sorry Barry = good point!

Currently I have a b/w condenser enlarger with a screw in / E27 75 watt bulb, which is white (paint?) coated and I use Ilford MG filters under the lens.

And as previously mentioned I have bought, to try out, a B+Q (a British DIY store) own branded 'Diall' WARM 2700k LED bulb, with an equivalent output of 75 watts = actually being 9.2 watts.

Terry S
Hi Terry, Ihave been using a Dial 2700 LED bulb for around 2 years now with great success, I tied both the cool tone and the warm tone Dial and found the warm tone 2700 dial LED to work better than the cool tone, the 2700 is about the same as the same as the photocresnta bulb, and have never had a problem with warm up, less than a second when first turned on seems to be negliadge, I use a RH analyser/pro, and the LED s geat with it, no heat, no negative popping, with the photocresnta the enlarger, a Meopta Opemus 66, was to hot to touch after a print, with the LED no heat build up, I am very happy with the bulb, I also find that although my bulb is rated at , I think, 14.5 which equals around 100 watts the light is brighter than the old 150 watt bulb, around 1 stop extra,
Richard
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Old 8th March 2019, 03:56 PM
Alan Clark Alan Clark is offline
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Quote:
Originally Posted by MartyNL View Post
Sorry Alan, what I was getting at is that I'd prefer to avoid having such short exposures and thus effectively eliminating the problem.
Marty, I agree that short exposures can be a problem. The 11W LED bulb that I have been using in place of the old 75 W incandescent bulb in my Leitz Valoy 11 is 20% brighter. But I don't have short exposures. A typical exposure would be about 20 seconds with the enlarger lens at f8.

Alan
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