Latest session

[JohnFP]

Well, I am almost ready to start making holograms again. I had the dangest time trying to regulate the water supply to the laser. I tried 3/4 inch hose, no go. I tried putting the power supply and laser and the hoses at the same height, no go. I tried eliminating the filter, no go. I had great pressure and flow to the power supply but after the power supply and laser too low. I thought, oh no, the hoses are kinked in the umbilical cord. Well as a last resort I reversed the flow of water through the supply and laser head. It did not seem to flow any better. But then when I put the flow back in the correct direction, yeeeeeee haaaaa!!! I have great flow at 38 PSI. I then set up an interferometer and tweaked in the laser and etalon and I have the most contrasty fringes I have ever see. At least 3 times as contrasty. Very, very stable. I can change the power, all the way up to 30 amps and still great fringes. I can even dial from 488 to 514 and still great fringes. If I increase power or move to another wavelength I have to let the laser stabilize for about 15 minutes to get rid of the slow drift but great, great fringes, literally jet black and bright blue. I am so excited. I think I am going to really have great success in the near future.

I cannot believe I have not regulated the water pressure before this. No wonder I had to have short exposures, longer and the fringes moved as a result of different cooling rates because of the nature of my well pump and where it is set to go on and off now. I was even able to increase the pressure of the water for the house as now it is regulated for the laser. I had it turned down so the highest it would go was 45 PSI.

I also took the next step and built a self contained interferometer that I will introduce before the shutter. This way I will be able to monitor the fringes from the laser and expose accordingly. I believe, but have not tested yet that exposure duration in DCG is more lenient then silver. In other words if I see the fringes start to drift (still using an air spaced etalon but I have an oven controller coming for my oven controlled etalon) I can close the shutter and use the less then wanted exposure time knowing the fringes up to that point are stable and contrasty. It will also help me to determine when to expose knowing what the laser fringes look like at the time the shutter is opened.

This could not come at a more perfect time because I believe some test emulsion material is coming that needs 514. I always shoot in 488.

I am really excited and cannot wait to produce my next batch of DCG.

Peace and happy weekend to all!!!

[JohnFP]

Boo hoo. My plates just sit in their box waiting to be exposed. We had a storm Sunday Night and we still do not have power as of this morning. Guess I will be able to test how long the plates will keep in the constant temperature of the cellar (68 degrees F.) and still be good after all. Boy, I never thought camping out in your own home was so hard. No electric. Luckily we have a stream on the property for flushing, had to buy drinking and cooking water, have to fire up the generator about every 4 - 6 hours to keep the basement less then 4 inches of water and chill the refrigerators and no heat!!! We did get to bond and play charades with the boys until dark. Then early beddy byes.

But, just another reinforcement and reminder of how lucky my we are!

Peace!