Lab Notes

For what seems like forever now, I've been working on developing a DCG process for myself that I could use when making white-light copies of my silver masters.

After some inconsistent results I stripped the table top of all components and set up an interferometer to see how stable the table was.

I've been working on a couple of holograms recently and while I don't have a lot of time for blogging at the moment, here are a few pictures.

The dancing shoes turned out really nice both in master and copy.

The next one was a quickie for Wifey and her mother.

It's a commemorative pitcher from Union Station in Ft. Worth.

VRP-M is working out pretty well so far, even the old film from Oct 2005 is coming out ok.

OneNote has been written about ad-infinitum as a tool for note taking in meetings and classes, as a general information repository and as a collaboration tool but I'd like to introduce you to another use that I'm putting OneNote to.

Making holograms.

Or more specifically, documenting both the process I go through when creating a hologram and the results from that process in the form of notes and pictures.

As most of you will probably know, OneNote is a great repository for all sorts of information. It has allowed me to combine a number of sources into one place so that when needed, I can easily refer back to previous results when I'm making a new hologram.

For almost two months now, I've been working to figure out the exposure and processing steps to use in order to get bright and clean transmission holograms using my Coherent 315M and VRP-M film.

After blowing through roughly 68 pieces of film (mostly 1.5x1" in size) I think I've finally nailed the process to use for transmission masters.

JohnK on the holography forum had asked if I'd experienced any problems with delayed development of VRP-M.  He's been working on making holograms using a Coherent 315 and VRP-M film and was wondering VRP-M was sensitive to delays of several hours between exposure and development.

I normally develop right after exposure but did the following test to find out how VRP-M behaves.

It's time for another labcast and this time I'm experimenting with making a copy onto PFG-01 from a test "master" made using the 315M and VRP-M film.

The final test turned out pretty decent and was exposed for 12s, developed for 30s in TJ1 and bleached with EDTA.

The final image isn't as bright as I'd want if this weren't just a quick test but overall it's not bad. I may have time tomorrow morning to try another test with fresh developer but then again all my time might be spent watching the lunar eclipse.

Here's the cast. Let me know what you think.

If you find yourself needing to take your laptop into the lab, you can make life simpler by making a safelight cover for the screen.

I know most of you who make holograms don't carry around a tablet and those who carry around one probably don't make holograms but for others who, like me, do both, here's a way to take the computer into the lab without having to turn the screen off while film is out and about and you can save your "night" vision for what is probably a dimly lit lab.

I don't know how often I'll do these but I had the urge to record what I was doing in the lab.

I've been trying to get good results with the coherent 315 laser and VRP-M film and haven't had any luck. In each case where I've gotten any kind of image, it's been extremely dim.

Unfortunately I found that my shutter was causing a full seconds worth of ringing in the table and had to build a new shutter. That was completed yesterday and this morning I'm doing some more exposure and development tests.

My apologies for the sound quality. Next time I'll have to make sure the microphone is closer to me at all times.

Without further ado, here's my labcast.

Let me know if you'd like me to do more of these.

It's taken way to long to get the new Coherent 315M integrated in my lab (insert excuses here) but that's now been completed.

The power and shutter controls have been wired up, the software has been updated to control a third laser and it's been tested and is ready for use.  One thing I seriously need to do is refactor the HoloController source so that it's simpler to control an arbitrary number of lasers.

The layout shown above is the one I used to create a transmission master for a professor at A&M.  I was surprised to see that the beads which I'd painted fluorescent orange show up yellow under green light.  It'll be interesting to see how they come out when shot with green-sensitive film. 

The red in the background is from my copy layout which uses a HeNe.  The red dot in the middle-right is the beam from my red mastering laser.  Ordinarily it would be shining on the subject in the foreground but it's being blocked by the transfer mirror used to "inject" the green beam into the mastering path.

Click on the image for a larger version.

You ever look back at something you did months ago and wonder, "why did I do that?"

I did that this evening with the controller that I've got in my lab.

I'm starting work on another hologram for a professor at A&M and needed to do a bit of maintenance on the table. Strange, but every time a new hologram request from her comes in, there's something that needs doing in the lab before I can get started.

This time the HEPA fan wasn't shutting off during an exposure and the table light sensor wasn't working.

It turned out with the HEPA fan that somehow I'd wired up the relay connection with an additional 5v going to it. I have no idea why I did that. Fortunately it just caused the controller chip on that port to heat up (and not work) but didn't blow anything. Odd that it was working for a while and then just stopped.

The light sensor just turned out to be a loose connection at the junction between the table wiring and the controller wiring. Gremlins.

I also found a problem with the holocontroller software not always shutting off the fan and fixed that.

Now I just need to straighten up the lab, prep some film, paint the subject and shoot. All tomorrow morning.

I spent some time on Thursday night finishing up the platform for the new laser.

I've got a Kee-Klamp scaffold over my table that holds the big red laser and nothing else. I had planned to hang optics off the scaffold but that didn't quite work out. Fortunately it made a great place to put the SP-907 laser box.

Now it's got another rider in the green laser, telescope and shutter.

The dolmen work is proceeding. Things have been slow this week but since the last update I've made masters for the main dolmen and the lit interior.

Here are two thumbnail views of the transmission masters.

Continue reading "Dolmen work III"