Not with a glass carrier, which maintains negatives flat regardless of the fact that they're noticeably heated. With a glassless carrier, it most definitely does cause significantly more deviation from flatness than the slight amount negatives already exhibit when cold.Originally Posted by Luis-F-S
You enumerated them yourself in post #7.
IMHO, a word: No, except to make money for Heiland, the LED head manufacturer!
Since photographers like to think up problems that don't exist, I measured the temperature rise on a 6x6 negative with an IR thermometer in the standard glassless carrier, on an LPL 4500-II with a VCCE head, being turned on for a total of 10 minutes. The bulb was the 250W halogen recommended for this enlarger.
negative temperature at start: 66.9°F
light on for 1 minute-negative temp: 74.5°F
light on for 2 minutes-negative temp: 76.2°F
light on for 3 minutes-negagive temp: 79.4°F
light on for 4 minutes-negative temp: 83.9°F
light on for 7 minutes-negative temp: 83.9°F
light on for 10 minutes-negative temp: 83.3°F
So it would appear that the temperature at the negative stage stabilized after 4 minutes or so. The negative remained in focus the entire time. There is no negative pop at 83-84°F. If you get it to pop at that temperature, you have much bigger problems.
How often do you replace the EVW bulb? I'm still on the original bulb I put in the enlarger. I've bought some 50 odd EVW bulbs at auction for an average cost of $3.48 ea. And how much does an LED head cost?
A 16.4°F rise most definitely distorts a 4x5 negative in the LPL glassless carrier. Concomitant decrease in relative humidity of the emulsion makes this pronounced.
That's your opinion, have anything to back it up? I use glass carriers, so I don't have a horse in this race, besides, I print sheet film in a 5108 NOT the LPL, which I only use for 6x6 and 135. Besides, most enlarger exposures are in the 20-30 sec range in which time, the temperature increase will be negligible.
Last edited by Luis-F-S; 26-Jan-2020 at 14:02.
Your data from post #12 and my experience with 4x5 sheet film in both glass and glassless LPL carriers in my 4500II.
Yes, minutes and not seconds and my 35 year experience with 4x5, 5x7 8x10 and 11x14; and enlarging in both glass and glass-less carriers gives a different opinion from yours!
Luis, please give it a rest already. My experience with a 4500II is the same as Sal's. He's not making this stuff up.
I ordered the Heiland set up from Catlabs today. I'm just not that interested in a project and the upgrades sound worth it to me.
Good luck, please do let us know what you think once you've had a chance to use it!
Indeed, and, if possible, please include some pictures of the installation. Thanks in advance.
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