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> Light output of 240 W Enlarger bulbs |
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#11
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Watch this space!! Mike |
#12
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Again, watch this space and I will get around to doing what you have done in due course. Mike |
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White LEDS use a phosphor coating stimulated by a blue LED to generate white so their spectral output is different to a tungsten lamp. Tungsten output gets brighter as you go from blue to red and LEDs are somewhat more even with a peak around green falling off on both sides and a smaller peak at the blue end. So, again, it is probably a case of suck it and see with differences probably restricted to the equal exposure function of Ilford contrast filters going out the window, but still perfectly capable of getting all the grades. But that is just hypothesis based on spectral output graphs I have seen - I've not tried it.
[Edit: thinking about it, I suspect the grades obtained may drift as well as I think the filters are subtractive rather than additive (i.e. they pass the compliment colour rather than pass the active colour of the different hard and soft emulsions). As before, suck it and see seems to be the only practical answer... Last edited by Bob; 24th June 2021 at 06:52 PM. |
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Thanks Bob for the lumens explanation.
Mike, it could be an interesting exercise to see prints side by side revealing not only the difference in exposure time but also indeed if there is a shift in contrast.
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MartyNL “Reaching a creative state of mind thru positive action is considered preferable to waiting for inspiration.” - Minor White, 1950 |
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Terry S |
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