OC filters in our future?

[Jac@stafford.net]

Sodium vapor will fog paper.

You have had some bad luck, Eric.

My Thomas lights do not fog. They each have two sets of filters one of which slightly changes the color of light, and they have doors to lower light intensity more if necessary. (I got new filters a few years ago. The first filters lasted almost thirty years.)

[Leigh]

Sodium vapor will fog paper.

Sorry, Eric, but...

Not true in my tests.

I left a piece of paper, partially covered, on the counter for an entire printing session (several hours).

As the last activity of that session, I developed that sheet of paper.
I could not identify the area that was covered.

- Leigh

[Eric Woodbury]

I don't wish to hijack this topic, but to scratch other's itch, no, I have not owned a Na vapor lamp. I have two good friends that have tested them: one the late-great Al Weber and two a colleague of his. Both did threshold testing and found fog. Furthermore, check the spectra of either low pressure or high pressure sodium and find lines in the blue and green areas, albeit not large, but present.

The point of this link is OC filters in our future. I don't think there is any reason for filtering tungsten black body radiation with an OC filter for what you can get readily, reliably, and lower power from either an amber or red LED.

If you have success with Na vapor, then this doesn't apply to you. If somebody wants a good safelight for $5 or less, use LEDs.

[Leigh]

I have two good friends that have tested them: one the late-great Al Weber and two a colleague of his. Both did threshold testing and found fog. Furthermore, check the spectra of either low pressure or high pressure sodium and find lines in the blue and green areas, albeit not large, but present.

There's an old saying: "Ye shall find what ye seek."
That applies to almost any quest.

What your friends obviously missed is that the Thomas Duplex safelight is equipped with filters to eliminate that extraneous energy.

Apples and cumquats.

- Leigh

[Old_Dick]

192.168.x.x is a non-routable IP address block.

It cannot be accessed by anyone outside of its own physical domain, like over the internet.

I tried it and got:
Non-authoritative answer:
Name: subclub.org
Address: 69.49.101.19


I tried that IP address and it failed.
It also fails a PING, so it is not accessible over the internet.

However, when I accessed subclub.org, it worked.

- Leigh

192.168.0.1 is my router. I don't understand how it can work if it can't be resolved by ping, nslookup or traceroute. What do you have in /etc/resolv.conf ?

[Jac@stafford.net]

[...] I have not owned a Na vapor lamp. [...] I have two good friends that have tested [...] and found fog. [...] I don't think there is any reason for filtering tungsten black body radiation [...]

Bogus in too many ways including hearsay, and how does black body radiation relate to this thread? Impression is not science.

[Leigh]

...how does black body radiation relate to this thread?

A tungsten lamp is a black body radiator, as opposed to an LED, which is not.

He's talking about filtering light from a tungsten bulb, using an OC filter.

- Leigh

[Jac@stafford.net]

A tungsten lamp is a black body radiator, as opposed to an LED, which is not.

He's talking about filtering light from a tungsten bulb, using an OC filter.

- Leigh

If a source can be seen, or it's measured to be more energetic than ambient radiation (light), it is not a black body.
.

[Drew Wiley]

Beehives and the full range of filters are still easy to acquire; and the relevant specifications for each type of filter is still accessible info. Since I do a lot of color work, I'm accustomed to navigating in total darkness. Even my beehive for b&w paper Dev is on a momentary-contact footswitch. I never leave the safelight on. There is no silver bullet. When in doubt, test first.

[Leigh]

If a source can be seen, or it's measured to be more energetic than ambient radiation (light), it is not a black body.

You obviously do NOT understand the concept of a "black body radiator".

Look it up.

- Leigh