Search found 225 matches

by Din
Tue Nov 12, 2019 12:00 pm
Forum: Beginning Holography
Topic: Two issues - losing an object beam and spots on plate
Replies: 17
Views: 3357

Re: Two issues - losing an object beam and spots on plate

I think it could be motion. But, I think it's more likely that the light reflecting from the object is missing the plate. If your angles are correct as drawn, most of the light hitting the sides of the skull are reflecting away from the plate. I would look at just the object light (no reference) thr...
by Din
Tue Nov 12, 2019 11:47 am
Forum: holoforum administration
Topic: Denial of Service Attack (more or less)
Replies: 4
Views: 995

Re: Denial of Service Attack (more or less)

If it's of any interest, I'm receiving a number of emails with Chinese characters. I just mark them as 'junk'. But, I wonder why I'm receiving these Chinese emails, and is any other holographer also receiving such emails?
by Din
Sun Aug 04, 2019 8:43 am
Forum: General Holography
Topic: Apodizing filter
Replies: 2
Views: 3146

Re: Apodizing filter

I wanted to use a apodizing filter to get a better uniform object light to make a reflection hologram. Is that a bad idea? Does it affect the polarisation or other laserlight parameters? No, it won't make any difference to any laser property, besides, of course, beam profile. Whether it's a good or...
by Din
Tue Jul 23, 2019 9:33 am
Forum: Beginning Holography
Topic: 3D Silhouette
Replies: 5
Views: 7851

Re: 3D Silhouette

It's for designing objects for 3D printing. It works with the Sillhouette Alta 3D printer. We use Blender for creating objects for 3D printing.
by Din
Mon Jul 01, 2019 8:06 am
Forum: General Holography
Topic: magnified hologram
Replies: 14
Views: 6707

Re: magnified hologram

The transverse magnification of a hologram recorded with reference at x(r), y(r), z(r) with an object at x((o), y(o), z(o), and reconstructed from x9c), y(c), z(c) is*: MT= dXi/dxo= 1/(1 +/-zo/mu*zc–zo/zr)(Meyer; paraxial) MT= (cos(alpha)o/cos(alpha)i){1/(1 +/-zo/muzc–zo/zr)} (Champagne; non-paraxia...
by Din
Thu Jun 20, 2019 8:02 am
Forum: DCG
Topic: Ferric ammonium oxalate tests
Replies: 118
Views: 38043

Re: Ferric ammonium oxalate tests

And if i understand correctly, crosslinking with ferric happens only in developer, so you can't determine FEG emulsion's sensitivity in real-time. I don't know about Fe, but, in general, cross linking occurs at exposure. That's why you have an exposure time, to allow cross linking to take place. Bu...
by Din
Wed Jun 19, 2019 8:07 am
Forum: DCG
Topic: Ferric ammonium oxalate tests
Replies: 118
Views: 38043

Re: Ferric ammonium oxalate tests

If you set up a Michelson, and put your plate with your emulsion into one path of the Michelson, ie between one mirror and the beamsplitter, then, as the material absorbed and cross linked, the density would change. As the density changed, the index would change. As the index changed, the phase of t...
by Din
Tue Mar 26, 2019 8:49 am
Forum: Beginning Holography
Topic: Understanding transmission holograms and HOEs/gratings
Replies: 4
Views: 3781

Re: Understanding transmission holograms and HOEs/gratings

1) what is the difference in setup between diffraction gratings and transmission holograms? A diffraction grating is simply two beams, no object. You illuminate the plate with two beams and you have a grating. If the two beams are from the same side, you have a transmission grating, also called a '...
by Din
Fri Mar 08, 2019 6:13 pm
Forum: Beginning Holography
Topic: Drying silver halides emulsion with alcool ?
Replies: 7
Views: 4240

Re: Drying silver halides emulsion with alcool ?

Drying in alcohol works well for Agfa plates. It doesn't seem to work so well for Slavich plates. The issue may be that you're not setting up the plates to dry vertically. After the photo-flo, you have to prop the plates vertically, or at an angle, with a paper towel underneath to absorb the water a...
by Din
Wed Oct 03, 2018 8:22 am
Forum: AgX
Topic: Ultimate U08 / Bleach : reversal or rehalogenating ?
Replies: 8
Views: 5255

Re: Ultimate U08 / Bleach : reversal or rehalogenating ?

The smaller the grains the more image modulation is of the phase type. Maybe someone with better insights into Raleigh and Mie scattering theory could elucidate on this. Well, roughly, Rayleigh scattering is predominant for small particle size, roughly 10% of λ. Rayleigh scattering is direction ind...