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.
"She's always out making pictures, She's always out making scenes.
She's always out the window, When it comes to making Dreams.
It's all mixed up, It's all mixed up, It's all mixed up."
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?
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.
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.