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Hi Tony, thanks for the tip, I will keep it in mind. I was using plastic syringes which had silicone oil (presumably) to lubricate the rubber portion of the plunger. Pits resulted after using this (with a syringe filter), but no pits were seen when the emulsion wasn't filtered with the syringe. The ...

This is the same hologram reprocessed with 68C 100%. Much brighter, without any noticeable difference in bandwidth. Thanks for reminding me! In transmitted light, the plate is clear. For some reason the camera is picking up some blue glare which is mostly absent when viewing the hologram by eye. It'...

Thanks for your thoughts about the warm water bath. So far in my tests, a wavelength shift upward (towards red) is preferable to a blue shift, because there are methods (such as prolonged baking) which can shrink the layer back down. On the other hand, if there is too much shrinkage, it's quite chal...

A (still blurry) photo showing blue figure on left. The previous hologram was re-processed today with a higher water temperature. My beam alignment (reflecting off the spherical mirror) was off: too much green on the right, and too much blue on the left.

I had problems focusing the photo, the figure on the right was focused, the others weren't. This is a two-color DCG hologram done today. Still trying to find a film formula that is reproducible, but I've made quite a bit of progress in the last couple days. P1010037.JPG This test hologram was re-pro...

Thanks Dave, that makes good sense. Part of my problem was over-loading the emulsion with dichromate when exposing at 488nm, as you suggested. I watched the plate as it was being exposed and saw a huge amount of scatter coming off the emulsion (it looked a little like frosted glass) when being expos...

I've had some crystallization problems with G307. It may be due to the cool temp of 16C (60F) used when drying. When immersing the gelatin layer in the 5% solution of potassium dichromate (with a little glycerol and Photo-flo), it comes out clear, but after drying a while, white crystals form, espec...

Can you take photos? If you want to degass water for an emulsion, I recommend getting an inexpensive distiller, for example, a medical one. The resulting distillate has a low gas content in the first hours after receipt or if hermetically sealed. You can keep a gelatin solution under ultrasound for...

Thanks for the detailed info. Also, to make sure the mix was thorough, I added two-three drops of photo-flo to the gloop. So far, I haven't added photo-flo, but want to try it. When mixing my DCG (I use mag stirrer also) it's obvious that it takes some effort to mix it well. In the glass bottle of e...

In the past, I've noticed "pits" in my coated emulsion. I call them pits, because they seemed to be what Richard Rallison described in his 1994 Lake Forest notes: "These "pits" have the appearance of small circles of various sizes and scatter themselves throughout the plate....