633 safelight

[Johnfp]

Not sure, but I was digging for a safelight in my "stuff" and I only had red LED's. But I have two flouresence black lights. I looked at them with my handy dandy Project Star Spectrometer and i see no red at all. Just from about 500nm and lower. Seems to be real good.I will let you know how they work out.

[Jeffrey Weil]

Hello Johnfp,

All silver is natively sensitive to UV. All the absorption dyes do is bring some sensitivity to the visible range. The emulsion is still sensitive to the UV.

Your black lights will fog the emulsion pretty badly.

Jeff Weil
NorthBeach Holography Inc.

[Johnfp]

Huuuum, well, thank you very much. Save my butt a plate and I would say a bit of frustration.

Maybe I should start posting in the beginners section. Can't believe the things I have either not known or forgotten.

Thanks a millions. Truely!!!

[142laser]

OK jeff so what is the best safe light for this media? Incandescant with a good green filter? Mercury does have a red line even with a green filter and a UV absorber so that is no good.

[Johnfp]

Well, if you want to see a spectical (hehe ...you'll get that later) come to Home Depot up by my house tomorrow about noon. I will be wearing a yellow pair of diffraction glasses. They are solid plastic and very slim line and wrap around to the ears. Almost like future space goggles. Sort of like these but yellow.
http://fruitycat.files.wordpress.com/20 ... -white.jpg

I will be looking at all the LED's and christmas lights they have looking for that nice, cheap safe light.
Go to Home Depot and search their site for "green LED".
They have green night lights
Green Beacons
Green LED minirope
Green LED christmas lights
and
Streamlight Stylus Green LED Pocketlight

But be careful, they seem to use the word green as a buzz word for energy efficient.

So I will be looking at a variety of these through my diffraction glasses and see if I can make a spectral spectical of myself...

If I find something good and cheap I will let you all know.

[Jem]

John, do you happen to have a green laser laying around?

They make a perfect safelight for working with red sensitive silver emulsion. You just need to stick a lens in front of the aperture to expand the beam into something usefully large

[142laser]

Sure...a 1/2 watt might be enough. How about a nice used Laser Quantum GEM? Only $1,250. Come on, lets be real.

[Jeffrey Weil]

OK jeff so what is the best safe light for this media? Incandescant with a good green filter? Mercury does have a red line even with a green filter and a UV absorber so that is no good.

Hello 142,

Johnfp beat me to the punch on this one. LED Christmas lights on a dimmer. That's my favorite. They come in red and green. Look for the kind that have some other similar colored plastic thing over the LED. So if the LED's themselves are red, look for something that also has red balls, or berry's or whatever over them.

That extra filter will cut out any stray lines you don't want. Green LED's have a little red light in them, the green plastic thing will get rid of that. The dimmer is important, just use a regular type designed to go into a wall switch box. Make sure to insulate the connections well. The LED's will probably be too bright without it.

The main reason I like the LED's is you can string them over the whole table. Back and forth in rows on the ceiling. If you use a standard safe light, one bright light in the middle of the room, you have a super bright spot and it falls off quickly so the other parts of the room/table are in the dark. Even worse, that single light makes such major shadows over everything its hard to see all the sides of your equipment.

With the LED string and dimmer combo you have a nice soft even glow everywhere. No shadows anymore.

Next is the classic holographers switch. Take a pull cord switch. The ball chain type that has a spring return. You can get them in any ace hardware for just a few bucks. Mount that over the side of the table you work mostly from. Mount it on the wall about 2 feet over your head. Now tie a string to the pull ball chain and connect it to the other side of the lab. On the opposing side the switch is mounted to. Make it so there's a little bit of tension. Just enough to keep the string pretty straight.

Hook the switch up to the white lights in the room. Not the safe light, you can leave that on all the time, the room's white light. Now you can turn the room light on and off from anywhere along the tables length by just reaching up and pulling on the string.

Much easier than going to the wall switch 50 times a day.

Jeff Weil
NorthBeach Holography Inc.

[Jem]

Sorry Phil, I just don't get your sarcasm & think it was uncalled for. Unlike your commercial post, I was trying to be helpful.

Please tell me what exactly is wrong with using a green laser as a safelight? Maybe if you're working on an 8' x6' table or in a huge room it may not be enough. But for the average amateur holographer in a small lab it's quite acceptable.

It doesn't have to be SLM or anything particularly expensive. I use a small 20mW JDSU Microgreen, but it could equally be any other green laser. Even a cheap pointer would probably work if sufficiently heatsinked.

Once the beam has been expanded it provides plenty of light to work by and it is totally film safe.

I've now taken a 'chill pill' and i'm back to my calm self

Jem

Sure...a 1/2 watt might be enough. How about a nice used Laser Quantum GEM? Only $1,250. Come on, lets be real.

[Tom B.]

Re using a green laser as a safelight for red work, I must admit it seems ... perverse. Like using caviar for axle grease. I do agree that all safelights should be treated with suspicion. Most green LEDs do emit some red. Easy to check by looking at the diffracted spectrum from a CD or DVD, e.g. http://astro.u-strasbg.fr/~koppen/spect ... lesse.html