I did some research on LED bulbs, and was left with doubts about their suitability to the enclosed housing of my Omega enlarger. I also had questions about lag time to start and afterglow as well as the output spectrum when using VC papers.This may be a case for trying an led bulb to eliminate the heat problem. Not sure which brand works the best but Id bet there a few members here who has been there done that.
In my opinion a glass negative carrier is a must to get a flat negative despite the additional concern of keeping it clean of dust, and I'd get a halogen bulb to avoid the disadvantages of cold-light head(warm-up).I've currently got a Beseler 23CII XL and Leitz Focomat v35 in my home darkroom. The stock 23C with the proper replacement bulb gave me very short print times, even at f8, so I ended up using an ND filter to cut back the light. Even so, I routinely experience negative popping from the heat generated by the bulb, despite the use of the Beseler heat absorbing glass. This obviously causes corner focusing issues (I have a glassless negative carrier) unless I wait for the negative to pop and stabilize, and I don't like the thought of my negatives being subjected to that kind of heat during printing.
I bought the v35 in the hopes of having a better printing experience. The enlarger is a joy to use, but I've now been experiencing long print times with it - exactly the opposite of the 23C. I believe this is because the enlarger was designed around a Philips bulb that is no longer available and the replacement bulbs don't transmit the same amount of light to the light box because of their wider beam spread. I do tend to overexpose my negatives a bit in the hopes of retaining shadow detail, but they are not what I would consider bulletproof. And these negatives print with comparatively short times on the Beseler, so I have to believe that the bulbs are the culprit, and there are other threads online describing similar issues. I do have a glass carrier on the v35 so at least there are no popping/focus issues.
So, in summary, I have long print times on the v35 or short times/popped negatives on the Beseler.
It seems I have a couple of options. Get a glass carrier for the 23C, but still subject the negatives to high heat, or get a Heiland cold light head for the v35. Both solutions would cost more than I paid for the enlargers/lenses. Maybe there's a different enlarger that I should consider that will solve both issues without breaking the bank. I may end up springing for the Heiland since I really do love using the v35, but I do plan on printing MF at some point so resolving the issues with the Beseler also seems like a worthwhile pursuit.
Any thoughts/suggestions would be appreciated.
I don't know of any existing sources of the Philips 13139 bulb. It seems that there are some sources of 'replacements' but the specs of the bulbs are not the same and the bulbs produce less light. I've tried a couple and they resulted in print times that are much longer than I'd like - tolerable for 8x10 but too long for 11x14. The Heiland is probably the ideal solution but pretty pricey at about $400.If you plan on printing for a long time to come then get the Heiland head, or at least find a solution for the light source. I think there still are solutions. The V35 is way better than the 23c. I always thought those were poor enlargers. Always out of alignment.
In my opinion a glass negative carrier is a must to get a flat negative despite the additional concern of keeping it clean of dust
I use a 23CII also with the standard PH111A 75w bulb and don't have any popping issues with standard glassless neg carrier/no heat absorbing glass and normal contrast negs (8-10 secs/f/11 exposure times). Are you using the same bulb? Seems awfully strange that you're having negative popping problems; it's really not all that common a problem.
I did experience popping many years ago but that was my fault: I was cooking the negs a bit too long.
Yes, I'm using the same bulb. I should say that I assume the issue I'm having with the 23C is from negative popping. Here's what I'm seeing:
I focus the image using a grain focuser, and then leave the enlarger on and continue to observe the grain through the focuser. After a short time I can slowly see the grain drift out of focus...
I have the same issue with my 23C III XL. For whatever reason, the bulb is way too bright, even though it's the standard PH140. An ND filter helps with the short exposure times. Mine are even worse than yours. Without a filter, I'm looking at exposures of 6-7 seconds at f:11 on Illford MG IV.
To help with the negative popping, I only leave it on for about 30 seconds at a time, max. Then I'll let it cool off for a minute or two before reusing it. If I have it on for too long, I'll pull off the light housing to expose the bulb to more air and let it cool down quicker. It's a hassle for sure. But less of a hassle than using a glass carrier, in my opinion.
I believe the problem is leaving the bulb on for that extended period of time. I typically load the carrier, insert it and, with the grain focuser in place, switch on the enlarger and quickly focus. I switch the enlarger off and get paper out of the safe and place it in the pre-positioned easel. I then wait several more seconds for the vibrations to settle before pushing the button on the timer making the exposure, which is usually 10 or so seconds. This routine doesn't allow much heat build-up to occur. If the bulb is left on for an extended period of time beyond that of the routine described here I am sure there will be heat transferred and negs drifting out of focus.
I did some research on LED bulbs, and was left with doubts about their suitability to the enclosed housing of my Omega enlarger. I also had questions about lag time to start and afterglow as well as the output spectrum when using VC papers.
If you plan on printing for a long time to come then get the Heiland head
I have LED lights throughout my home. The ones in the bathroom have a definite lag time of at least .5 second. Many LED bulbs specs state that they are not to be used in enclosed fixtures.A true LED bulb does not have any appreciable lag time to start which is why they are getting more popular of cars. The switching on is instant - far quicker than tungsten. As for any after-glow, I have never seen any! I have 2 LED bulbs in my darkroom, one is for general light, the other is a cold light so I can assess the colour balance of prints. The degrees kelvin are around 7000 so it works very well. Switch on is instant and there is very definitely no afterglow what so ever.
Methinks you have been reading too many inaccurate Social Media reports.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?