How does development time/ exposure time/ bleach time /exposure angle affect the brightness and playback color of single beam reflection holograms? My first exposures were bright, but my 3rd and fourth batches are looking abysmal. also, what is the prefered method for using film instead of plates? also, after processing with triethanolamine, do I squeegee? dry before exposure? Thanks!
Ronny Andreassen - Fri, Apr 06, 01 07:35:35 AM
blueeyedpop, Exposure and develope time is important. The exp. angle is allso important when talking about brightnes. If you exp. the film/plate at appr. 45-57 degree you should be able to achieve very bright holograms. develope time is depending on which type of film U are using. When using PFG-03M U shold dev. until density=0,7 with GP-2 dev., and much darker if you are using orinary dev. + bleaches. The best dev. for these plates are GP-2. On BB640 plates you'll have to dev. until appr. D=2,5, and this will take min. 2 minute to achieve. Bleach untill the holographic film/plate is clear. It's much easyer to help U if you can tell a little bit about your processing and what type of film/plate you are using. I prefer plates rather film. With film U have to indexmatch on to a glass-plate (recommended) or sandwich the film between two plates. After TEA you have to squeegee, therefor it's recommended to add some few drops with Photo Flo in your TEA bath. After TEA U have to air-dry the film/plate for appr. 1 hour before exposure.....ronny 62.66.239.54
blueeyedpop - Fri, Apr 06, 01 09:15:47 AM
I failed to mention that I am using PFG-01 and GP2 chemicals.
Typically, I have been exposing 7-14 seconds, and developing for 7-1/2 minutes, as per the "shoebox" book. My plates actually turn dark in about 1-3 minutes. I am confused bu two things here, The "book" says to dev. for 7-1/2 minutes, and the gp2 chemicals indicate a 2 minute development. In addition, I was told by Intergraph that the bb plates require 1/2 the development time. I am still building my densitometer, but looking at by plates before bleack, I guess a density of 80-90% trans, or densitu of .7 to 1.0 .
I have never seen a plate go darker than this. Perhaps my impresion of transmission is WAY off.
As far as film is concerned, I have tried sandwiching between 2 plates, both with firm and loose clamping, but I get moire' patterns doing this.
I have also tried glycerine which is water soluable, both with a film/glycerine/glass sandwich, and a glass/glycerine/film/glycerine/glass sandwich. I am using ordinary 1/16" picture framing glass since water e\white float and 1/10 wave ground plates are a little expensive.
any further ideas? Is switching to pfg-03M the way to go if I never intend to do a transmission master?
Thanks! 64.63.88.51
Ronny - Fri, Apr 06, 01 11:43:33 AM
I have no experiences on PFG-01 film/plates, but if you take a look at GEOLA's site you'll see that the best dev. for pfg-01 is SM6 or Pyro. I have experienced that SM6 is the best on BB-plates, so my guess is that's the best on pfg-01 too. On the same site you can read about density too. To avoid patterns on the film you can try to expose the film under Brewsters angle (56,7 degree?) and rotate the laser until you have the right polarization angle (minimum reflection from the film). I'm using the PFG-03M to make single beam reflection and master holograms, and they are the best. Please take a look at Frank's linkpage, and go to Vidar Hegdals website. There U can see my results on PFG-03M. 62.66.239.20
Jonathan - Fri, Apr 06, 01 12:44:22 PM
Blueeyedpop - I've found that the best way to mount film on glass is to use "lamp oil" (the clear type). It's available everywhere, doesn't smell, isn't carcinogenic, doesn't evaporate before you're finished, comes off in the pre-wash, and best of all - it works. To completely eliminate unwanted reflection patterns ("woodgrain", etc.) you still need to arrange the reference beam at Brewsters angle and make sure the polarization of the beam is in the same plane as the incident and reflected rays (so-called p-polarization). The other big cause of unwanted "banding" effects in the hologram is stray reflections, especially from the plate or film holder itself. Good luck. 142.194.47.30
blueeyedpop - Fri, Apr 06, 01 07:38:01 PM
Yeah, the vertical banding caused by internal reflection in the plate is a bummer. I put a piece of electrical tape on the edge of the plate towards the laser, and this healps greatly. If I could figure out why the banding is soooo much brighter than my holograms. Perhaps it's a matter of more exposure.
Where is SM6 available? 64.63.88.51
Ronny - Sat, Apr 07, 01 02:22:20 AM
Where to buy SM6: I dont know, Make your own...it's easy. 62.66.239.33
Colin Kaminski - Sat, Apr 07, 01 07:16:21 PM
Do you use a light meter? I find I use much longer exposures for most of my holograms than the shoebox method. I have used pfg-01 and gp-2. Try making a test hologram with a mask and a slit and change the exposures across the plate. That is how I calibrated my light meter. Which is just a solar cell and ohm meter. I usually end up with exposure times of 45 sec with infiniter 200, pfg-01 and gp-2 for 2 minutes. All banding stoped for me when I taped ALL edges of the plate. I am making a plate holder to do the same thing. 64.167.151.217
Colin - Sat, Apr 07, 01 07:25:30 PM
Oh, yeah I also make sure I am vertically polorized but I not sure why. 64.167.151.217
blueeyedpop - Mon, Apr 16, 01 08:21:12 AM
I'm doing the solar cell thing, developing a log book of different exposures. I wontered if moving a mask in from of the plate would have the effect of fogging the back as the object light struck the entire plate, so I started using test strips of film. To check my polarization, I set my solar cell in the reflection of the light bouncing off of the plate, and rotated my laser until I received the lowest reading. I have been taping the edges, but I found flagging works well too.
The one thing that I wasn't minding too well, was the temperature of the rinse and chemicals. Now with the aid of fishtank heaters, I maintain everything at 74 deg F, and everything is beautiful!
Thanks for the help. 64.63.88.51
Colin - Mon, Apr 16, 01 12:23:54 PM
Edmund Industrial Optics has a good article on finding the polarization of a filter. Are you making transmission or reflection holograms? You have to mask both sides for transmission test exposures. 64.167.149.86
blueeyedpop - Tue, Apr 17, 01 09:05:27 PM
Colin,
Would you be interested in communicating more directly?
If so, I can be reached at blueeyedpop@colornetworks.net
Thanks 64.63.88.51
Colin - Wed, Apr 18, 01 10:49:04 AM
Of course I am the one who has that backwards. Single slit and anti-refelection backing for transmission and double slit (one front and one back) for refelection. My refelection test had a significant amount of internal reflections. I have been fighting my transmission set up and had it in the brain when I replied. My Infiniter does not stay in the same place in my mount from day to day. Everytime I go to the bench I have to realign all of the optics. 64.167.149.200