Filter to make IR Flash

holmburgers said:

And remember, Halloween is coming!

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I'm ready! Just got a new 10-pak of Rollei waiting for it.

nice!

Less than two weeks ago I won a lot of 32 GE #5R flashbulbs off of eBay for around $1 each. About 6 months ago there were a few GE #22R flashbulbs that sold. They don't come up for sale very often. Maybe twice a year. and they can be expensive.

FWIW, I just won some GE #5R infrared bulbs on eBay. And the other night I tried to mix up some dyes but it didn't work out; only because the solutions I had were too dilute. I've got many more dyes to test though, so that's the good news.

Anyways, these bulbs should set a baseline for IR flash that I will try to reach with my flash-coating.

I know it's been said, but I figured it wouldn't hurt to ask anew. Which IR film would you recommend for this?

Sjixxxy said:

Sounds like you are getting a lot less light then with an SFX Filter. I've been using a flash with a GN of 60 at ASA 100. Four feet at f/4 tends to give me negatives where the subject is of a nice density on the film.

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I have this exact set up; I use a flash with an (optimistic) GN of 30 meters, or about 90 feet. I get a decent neg with SFX film @ F.8 at 6 feet, so I think we're in the same ball park. The farthest I can go is about 12 feet at F2.8 (mamiyaflex TLR w/ 80mm 2.8 lens)

Tried the same set up with some EFKE IR 820 in 4x5 and couldn't get an exposure at any range. It would appear that the SFX is a bit "faster" than the IR 820, or its possible I waaay under developed the Efke IR 820 - I dev the SFX in Rodinal 1+50 for 13 minutes, but massive dev charts stated 1+50 for 9 minutes for the IR 820 - I'm thinking I need to add another 4 or 5 minutes to the dev time for the IR 820.

The gelled SFX filter, while expensive, works darn well, The flash is quite visible, however.

ntenny said:

I can't figure out whether the SFX filter is equivalent to 89b or not.

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I think it is (or it's very close).


Steve.

Word to the wise, there's a sizable stache of General Electric 5R infrared flash bulbs on eBay right now. About $3.33 a bulb and there's 72 available.

Pretty rare! I only mention them because I probably shouldn't buy them myself (though it's tempting..)