I hope you do not mind too much, if I'll give you a basic intro into safelights. As I can not refer to the mentioned lights as I simple use old Agfa filters with a 3 W halogenlight.(posted 9089 days ago)Usually, common b+w papers can be divided into two groups: - sensitive to blue light, unsensitive for 500 nm + - sensitive to blue and green light, unsensitive for 570/580 nm +
First group includes fixed grades e.g. Ilfospeed, Agfa Brovira Speed. Second group includes vc papers, Ilford Multigrade, Oriental VC, Agfa MCP, Kodak Polymax.
Most paper companies have published sensitivity versus spectral wavelength (nm)on their webpages, e.g. Kodak. So one may look up his choice of paper for exact data.
First group papers can be used with green/yellow filters, like Kodak 0A, this lights are relativlly bright, data sheets usually say 4 ft. distance 15 W light bulb for 2-3 mins.
Second group papers can be used with orange filters or dark yellows, usually orange filters are brighter, also 4 ft., 15 W, 2-3 mins. (I found out that Ilford Multigrade can work with indirect green-yellow for a quick handling, while Oriental definitly will not work with green-yellow.)
If using papers from both groups, consider a orange unit, maybe with a interchangable filter for green-yellow for extra brightness, using group one papers.
For testing safelights please refer to the Kodak publication "How is safe is your safelight?" available on their webpages.
Regarding warm up:
Hot lights like tungsten etc. change their emission spectra during warm up, they are shifted towards lower energy (this means higher nm values) which is no problem with papers as they are unsensitive to higher wavelengths.
Regarding brightness:
Your eyes will adjust to it.
Number of safelights:
30 sq.metres is rather large compred to my 6 sq. metres, so how about a smaller direct light and a bigger indirect light, I leave this question better to the folks with big darkrooms!
Summary:
Model: "Uhh, it is so dark in here!" Answer: "Guess, why it isn't called lightroom" (8^]
Wolfram (Different continent, different safelights)