
Piracetam crystals
Moderators: Chris S., Pau, Beatsy, rjlittlefield, ChrisR
Piracetam crystals
I've been using a plastic analyser for a while and finally managed to find a decent one. Here is a shopped picture of some new filters with shots of piracetam crystals inside them. 100 times magnified


- arturoag75
- Posts: 1600
- Joined: Fri Feb 05, 2010 1:05 am
- Location: italy
- Contact:
- Cactusdave
- Posts: 1631
- Joined: Tue Jun 09, 2009 12:40 pm
- Location: Bromley, Kent, UK
Clever idea and good execution, though if I was being 'picky' I think I would have arranged the filters on a different background. I'm not sure that background really compliments them. BTW they are Zeiss neutral density filters aren't they? I think I've got a similar set somewhere.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear
I think they are neutral density filters. I've never used such before but the one that has a value of 0,03 dims the light to a much higher extent than the 0,5 one.Cactusdave wrote:Clever idea and good execution, though if I was being 'picky' I think I would have arranged the filters on a different background. I'm not sure that background really compliments them. BTW they are Zeiss neutral density filters aren't they? I think I've got a similar set somewhere.
This is the reflection of my camera lens from the surface of the 0,03 filter.

And the actual filters. Both of them are zeiss, not sure about the third one.

The other filter transmits green light and reflects purple-ish colours (lower wavelenghts I suppose but I might be wrong)
As for the background I grabbed the closest textbook with a dark cover:

I had no intention of producing the image I posted so didn't really care about the background. I agree, I would've used a different one, not sure exactly what though

- Cactusdave
- Posts: 1631
- Joined: Tue Jun 09, 2009 12:40 pm
- Location: Bromley, Kent, UK
An interesting and amusing choice of background.
Lecturer, practitioner or both? My background was in cell biology and cancer research before retirement. I think the third filter would be a green interference filter, at least it is in the similar set I have.

Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear
None. I am still a student.Cactusdave wrote:An interesting and amusing choice of background.Lecturer, practitioner or both?
What is this set good for? I told a friend about a problem with the light intensity so he gave me this set of two 0.5 and one 0.03 neutral density filters plus the green one. He didn't really say what the original purpose of the set is.Cactusdave wrote:I think the third filter would be a green interference filter, at least it is in the similar set I have.
Perhaps this might give you a better idea of the green filter. I used a CD as a reflective diffraction grid to generate an incandescent bulb spectrum. The top image is (-)filter and the bottom one is (+)filter.

Then I used the filter box as a holder and situated my desk lamp on the right side of the image. You can see the reflection on the right and whats transmitted to the left.

Any information about the nature of this filter set and its applications are highly appreciated.

Then I used the filter box as a holder and situated my desk lamp on the right side of the image. You can see the reflection on the right and whats transmitted to the left.

Any information about the nature of this filter set and its applications are highly appreciated.
- Cactusdave
- Posts: 1631
- Joined: Tue Jun 09, 2009 12:40 pm
- Location: Bromley, Kent, UK
Good question. The neutral density filters were probably useful to help with exposure control in pre-digital photography days, while maintaining a fixed colour temperature. The green filter was probably used to increase contrast for photographing certain histology stains. There seem to be quite a lot of these sets around so I guess they were supplied as a standard accessory with Zeiss microscopes at a certain time.
Edit: BTW I love your innovative experiments with the filter.
Edit: BTW I love your innovative experiments with the filter.

Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear
This thread went a bit off-topic
so here are some actual shots of piracetam crystals. This chemical is somewhat difficult to use for that purpose since it easily forms clumps that are of no use in polarisation microscopy. I found out that spreading piracetam solution to a very large surface helps to make crystals of the appropriate size.















- rjlittlefield
- Site Admin
- Posts: 24396
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
Going off-topic is an honored tradition at photomacrography.net.bromodomain wrote:This thread went a bit off-topic

By the way, while I'm off-topic myself, I'll mention that the standard posting limits call for no more than 6 images per day in each image gallery. (The technical discussion forums are unlimited.) No need to modify anything you've done so far, but please keep the limits in mind for future postings.
Thanks!
And now back to piracetam crystals...
--Rik
I love going off-topic for the simple reason that I learn new things (as in this case). I just felt that people would probably like to see the crystals. I wasn't aware of the 6 images per day rule but I'll keep it in mind for future reference.
Therefore feel free to go off-topic.
Speaking of physics I'm still not sure how the psychedelic imagery in polarisation microscopy is generated. I know about the function of the polariser and analyser and that the colour is a function of thickness but when is the actual colour generated?
BTW I noticed that the green filter changed its transmission properties when tilted relative to the light source.
Therefore feel free to go off-topic.
Speaking of physics I'm still not sure how the psychedelic imagery in polarisation microscopy is generated. I know about the function of the polariser and analyser and that the colour is a function of thickness but when is the actual colour generated?
BTW I noticed that the green filter changed its transmission properties when tilted relative to the light source.
- rjlittlefield
- Site Admin
- Posts: 24396
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
The crystals rotate the axis of polarization differently for each wavelength of light. Strong colors occur when for some wavelengths the axis of polarization ends up crossed with the analyzer so that wavelength gets extinguished, while others are not and make it through.bromodomain wrote:but when is the actual colour generated?
Definitely consistent with being an interference filter.BTW I noticed that the green filter changed its transmission properties when tilted relative to the light source.
--Rik