Most photographic enlarger uses normally pretty high power of a light bulb up to 150W or even more, the heat from the light bulb would be a problem for the negatives especially long exposure. Now the LED bulb is becoming popular in the market, today I am going to test a enlarger light bulb and a LED bulb to see how different they are and would the halogen enlarger light bulb be replaced by a LED bulb?
enlarger light bulbs
My Fujimoto 450M enlarger comes with a Philips 150W light bulb and other 75w bulb from a LPL 7700C . I also grabbed two 13W LED light bulbs (warm and cool white color temperatures) from Philips to join this test. The measure tools will be Sekonic-758 and Minolta color meter IIIF. Enlarger lens is NIKKOR 135mm f5.6. The tests include directed light and through the enlarger lens. All tests keep in constant distance and position to measure the EV values and color temperatures. All data available below:
Measuring though lens
Meter reading
Measuring Data
Conclusion:
According the measuring data, 150W halogen bulb has 0.5EV more illumination value than those LED bulbs, but similar in through lens test. The LPL 75W bulb has 0.5EV less illumination value than the LED bulbs. The warm LED bulbs has around 3000K color temperature value which very close to the halogen bulbs. However the cool LED bulb has closed daylight color temperature which can reduce 50% exposure time definitely in term of the photographic paper is more sensitive to shorter wave length of lights. But in this stage, I still prefer using warm LED bulb due to have more time for dodging and burning during the exposure. From the result of the prints, cool LED bulb has slightly less contrast when judging carefully but almost similar to warm LED bulb. Finally, those LED bulbs have extremely less heat than the 150W and the 75W halogen bulbs, therefore the Philips 13W warm LED bulb won this test which fully replaces the halogen bulb. If anyone wants more exposure time, the 10W LED bulb would be other choice.
prints
LED bulb, Saving energy Saving environment, Protecting the your negatives.