Triethanolamine Squeeging

On: Thu, Aug 16, 01 03:55:06 PM

Brian wrote:

RESPONSES

Michael S - Sat, Aug 18, 01 02:37:40 AM

I'm not actually familiar with TEA, but I did find I good squeegy for putting holographic film on glass at Fred Meyers. It only cost $.99 and was cheaper than a single windshield wiper. I found it in the automotive section. It is has an ice scraper on one side and the squeegy on the other. It measures about 4" long. 12.18.158.25

Brian - Sat, Aug 18, 01 10:25:49 AM

Actually, does anyone know of a good source of information on using TEA? I'm looking for things like how long to soak, what concentration of TEA, drying times, etc. -B 66.69.244.199

Jonathan - Mon, Aug 20, 01 12:12:20 PM

I've worked with TEA for awhile and it's definitely one of the trickier aspects of holography. I've found that there are no fixed rules, only guidelines. One can't say that 7% concentration will always produce a yellow-green reflection hologram, for example. This is because everyone's lab is different, and there are a number of different factors that affect the outcome. But we all have the same two goals - a clean hologram, and a predictable colour. Squeegying requires your own technique, and practice. The blade has to be good rubber or it will smear and leave marks. I've tried a few wiper blades and they don't all work, especially the cheap ones. All you need to do is glue the blade (only) to a straight piece of angle bar, or something similar, and you have a squeegee. It should be longer than the film is wide, and it shouldn't be used for anything but TEA. For a backboard you can use ordinary glass, secured at 45 degrees just behind the tray. It must obviously be clean, and you need enough glass area so that you never have to place the film down on the same part of the glass more than once. If you do it will leave marks. Soak the film for a couple of minutes, remove it wearing gloves (latex are probably best) and let it drip for a few seconds. Then place it emulsion up on the glass, and swipe it once. Clean the blade off with a kleenex, and give it one more swipe. Pick the film up off the glass (use a single sided razor to lift the edge), and place it emulsion down on a clean area. Swipe twice, and again clean the blade between swipes. Now do it one more time. That is, pick up the film, place it emulsion up, and swipe twice, cleaning the blade off in between. This three-part squeegee routine (emulsion up, down, then up) really works, and is really quite quick with practice. Remember to wear gloves, because trying to handle the film with tongs is quite impossible, and TEA is an irritant. Let it dry thoroughly. A brief hair dryer boost, and a couple of hours in a drying cabinet or dark room will do. Overnight won't work, because TEA is also a chemical foggant, and the film will be fogged badly. You can save the TEA in a stoppered bottle and use again, though it tends to weaken with use and the colour will drift toward the red. I've found that concentrations between 4% and 10% are useful for the range of colour between orange- red and bright green. But other things come into play, such as the initial concentration of the product, type of film, and your method of processing. After all, the idea is control the degree to which the emulsion finally shrinks to in relation to when it was exposed, and there are more factors than just the TEA concentration. If you start with say 5% and go from there, recording all the details, you will find it fairly easy to get predictable results. 209.90.160.85

Tom B. - Thu, Aug 23, 01 04:27:29 AM

In an earlier thread, the use of an air knife was suggested. This is a blower head that produces a thin line of pressurized air that you sweep over the emulsion. Sounds like the perfect solution. Anyone have any experience making or buying such a thing? Stuff I've found on the web has all been heavy-duty stuff for industrial use. the earlier thread ("preswelling technics" or some such): http://207.16.155.247/webhf/archive1/217701931.html 24.67.253.203

Brian - Thu, Aug 23, 01 09:03:21 AM

Here's a thought I had that I'm wondering if someone can confirm: Seems to me that if I expose a room-temperature plate and then chill it right before developing it, then that should also result in a color shift as the chilling would shrink the emulsion and it should get stuck that way during development. Anyone ever tried that? -Brian 66.69.244.199

Colin Kaminski - Thu, Aug 23, 01 01:28:08 PM

Tom, All you would need as a way to create a laminar flow. I will give it a try and let you know. I can make an attachment for a hair dryer. I have some very light weight fiberglass around. I have some TEA on order and will try it when it arrives. Colin 64.167.148.132

S Valera - Sat, Sep 15, 01 05:59:52 AM

If you're using TEA just to obtain an increase in gel thickness, there are other, safer things you can try- Sorbitol and plain old sugar being just two. As with all things, experiment with different concentrations on test pieces. As for chilling before developing- no good. It is immersion in water that swells the emulsion. Temperature has little effect on a dried gel layer. Removal of material from the gel (eg sensitizers, dyes, AgBr) during development and bleaching results in a final dry gel layer that is thinner than the original dry thickness. 212.49.241.2

Xavier - Thu, Sep 27, 01 04:22:12 PM

S Valera, have you tried Sorbitol? If yes, have you good résults? 193.248.121.144

Kris Meerlo - Fri, Sep 28, 01 01:40:48 PM

I think I have the solution for the squeegee problems. Do the same as Jonathan. But try this blade ( squeegee ) The trademark is: LEIFHEIT Shower Cubicle Wiper. For shower cubicles made of frosted or etched glass and for all other surfaces. No streaks (TEA), no scratching. It works great for squeegying holofilm. Total cost in the netherlands about 6 dollars. 62.59.69.32

S Valera - Fri, Sep 28, 01 06:22:56 PM

Xavier, I have tried sorbitol (and sugar!) with DCG to increase the wavelength of exposed holograms. I have not, however, tried it pre-exposure. Suggest you use a used plate with a hologram and try different concentrations to see the variation of wavelength with concentration. 212.49.241.159

Sue P. - Sun, Nov 25, 01 09:21:17 PM

I have a project to do on the compound triethanolamine. Does anyone know any internet sites in which I can find the history of this particular compound (C6H15O3)N? It would be greatly appreciated. 168.191.90.187

Charles - Thu, Jan 24, 02 03:17:15 AM

Sue, try www.jtbaker.com/msds/t5291.htm 146.230.128.29

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