In what manner?gelatin filters change with time [during storage]
Then why do you need to make noises in a thread whose topic is... multigrade?? To show off your emoticons?- fine I never try Multigrade means - this was a good choice to avoid Multigrade
- what a nonsence means : Multigrade is nonsence to me.
Then why do you need to make noises in a thread whose topic is... multigrade?? To show off your emoticons?
In what manner?
In what manner?
Chemical decay. The colours fade. This is particularly true with filters exposed to strong light, and the manufacturers recommend to change them after a while (see for instance there, page 130). A gel filter on a 800W projector is typically thrown away a couple of days at most. Even for typical front-of-lens applications where heat is not a problem, Kodak only states a life expectancy of at least 6 months for their newer Wratten 2 series... and advertises it as a major improvement over the old Wrattens (see there). Of course, this is valid only in domestic storage conditions: humidity will cause fogging, dampness will destroy the filter immediately, and temperature above 50°C / 120°F will accelerate aging considerably. A cool dry place is where you must store gelatin filters to maximise its lifespan. Even then, a 35-odd years old gelatin filter is probably toast.
Chemical decay. The colours fade. This is particularly true with filters exposed to strong light, and the manufacturers recommend to change them after a while (see for instance there, page 130: https://www.kodak.com/uploadedfiles..._en_motion_newsletters_filmEss_15_Filters.pdf). A gel filter on a 800W projector is typically thrown away after a couple of days at most. Even for typical below lens application where heat is not a problem, Kodak only states a life expectancy of at least 6 months for their newer Wratten 2 series... and advertises it as a major improvement over the older Wrattens (see https://www.kodak.com/motion/produc...n/kodak_filters/wratten_2_filters/default.htm). Of course, this is valid only in domestic storage conditions: humidity will cause fogging, dampness will destroy the filter immediately, and temperature above 50°C / 120°F will accelerate aging considerably. A cool, dry, dark place is where you must store gelatin filters to maximise its lifespan. Even then, a 35-odd years old gelatin filter is probably toast.
Bugs will give them the rest - I forget to say.
with regards
Darkness is not the only condition and, although light accelerates chemical reactions, they do happen without it. "Several decades" is the key word here.So we can assume dark storage.
By whom? A source would be most welcome.Dyes used in light filters are regarded as not dark fading.
They aren't the same dyes, and I never said they were. Did I miss part of the conversation?We should not mix-up theses dyes with the chromogenic dyes in films.
Why keep posting? You're worse than Trump...
My last set of MG filters I bought around 1992/1993, and I was still using them until about April last year and they were still working fine, but I was placing a large order last April and thought, after reading here and elsewhere that they should be replaced every 2 or 3 years that I better get a new set,
I use 250w bulbs and that is the fear.I fear the 150W bulb in my Ic will fry my precious (new) filters... :lol:
Above the lens, which are gelatin, the below the lens are resinAre these below lens (gelatin) or above negative (resin) filters?
Above the lens, which are gelatin, the below the lens are resin
Richard
I never checked anything in such a a way, simply by putting prints side by side,new v old, and I could not see any difference in the prints grade for grade, but I say if it works it works, if it ain't broke why fix it,
Richard
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