Euastrum

Marek Mis · Post by **Marek Mis** » Sun Jul 11, 2010 8:51 pm

Polarized light, 1/4 wave length plate, retarder (?).
10 X Olympus S plan achromat, Lumipan - Carl Zeiss Jena microscope

Marek Mis · Post by **Marek Mis** » Sun Jul 18, 2010 11:39 pm

I've made mistake - euastrum was taken with 40 x not 10 x objective.

Ernst Hippe · Post by **Ernst Hippe** » Mon Jul 19, 2010 7:40 am

Hi Marek,

very fine picture! Did you also see tiny bright particles (crystals?) swarming around in the cell?

Regards Ernst Hippe

Marek Mis · Post by **Marek Mis** » Mon Jul 19, 2010 9:46 am

Hello Ernst,
I could not see any tiny cristals inside the cell, but the flares around it could derive from them. PerhapsThe Olympus 40 X S plan achromat is not enough good to resolve very tine particles. Could you see such cristals inside Euastrum Ernst ? If you look at my another picture - "Cosmarium II" you will be able to see similar flares around the cell. I don't know whet is the primary source of those flares. Do you have any idea ?

Ernst Hippe · Post by **Ernst Hippe** » Wed Jul 21, 2010 12:14 pm

Hallo Marek,
The pol. colours of these desmids come from their cellulose walls and look sometimes very impressive!
About the tiny double-refractive particles: I've seen them dancing in Brown movement in probably morbid cells. Your 40x objective can see this too.

Regards Ernst

NileRed · Post by **NileRed** » Thu Jul 22, 2010 2:51 am

Dear Marek, photo looks really nice, but are you sure that you used 1/4 Lambda, because backgroun color much closer to 1Lambda?

Marek Mis · Post by **Marek Mis** » Thu Jul 22, 2010 3:58 am

NileRed'
I'm not so experienced if about using additional various plates, and I don't know enough to discuss with you. However I can say you that plate I've used was 1/4 lambda (it is engraved on the surface of it). Additionally I've used "retarder" (?). The question mark at the end means that I'm not sure if about the name of that last thing. But I call it "retarder".
Both, the 1/4 lambda and "retarder" I've got lately from my friend and they suits to my Lumipan CZJ microscope
I can not to send the photos of these two plates because I've built them into common housing.
Best regards
Marek

NileRed · Post by **NileRed** » Thu Jul 22, 2010 4:20 am

Marek, I am not also a big specialist in pol microscopy, but if you for example prepare starch suspension in water, make photo at 100 or 400X, with 1/4 and #retarder#, or just #retarder# seaprately (if possible) and send it to me I can help us both to understand what #retarder# mean. All 1/4, 1 or other are named retarder or wave plates, but just #retarder# - God knows, probably 1Lambda, but combination 1+1/4 result in blue background (if I am not mistaken), it is also very important their relative orientation, so combination of 1Lambda with 1/4Lambda may result in yellow, purple or blue background. You can be interested in Michel Levy chart in google! Just enter Michel Levy chart...
With best wishes

Marek Mis · Post by **Marek Mis** » Thu Jul 22, 2010 4:51 am

NileRed,
Before I'll send you photo, I'll tell you that the combination of those three elements - polarizer, 1/4 lambda and my "retarder" gives very various colours, both the main subject and the background. It certainly depends on degree of rotation every of them.

NileRed · Post by **NileRed** » Thu Jul 22, 2010 1:38 pm

Hello Marek,
I have one more question. These 2 Daphia photos are really great, please could you tell me did you use stacking to get so high quality and also tell little bit how do you connect the camera to the scope?

Marek Mis · Post by **Marek Mis** » Thu Jul 22, 2010 11:15 pm

NileRed,
Those two images of crustaceans weren't stacked. If about my way of connection my camera to the microscope I'll try to take some photos next week, because I don't have it at the recent place. By the way you will be able to see the housing with polarizer and retarders.
Marek

Ernst Hippe · Post by **Ernst Hippe** » Sat Jul 24, 2010 2:11 am

Marek,

as far as I know the crustacean shell is normally not so colourfull in pol. light, only in ostracodes. So the colour seems to come from crystals attached to body or shell. I observed those some time ago, but coud'nt clear their origin. Your finding is therefore very interesting for me!

Ernst

Marek Mis · Post by **Marek Mis** » Sat Jul 24, 2010 2:40 am

Ernst,
You are right if about colours in simple polarization. But apart from polarizer and analizer I lately use additionally quarter-wave plate and another "retarder". Their combination, separate rotation and appropriate settings give very various colours. I was also very surprised if about effects which give those three elements. Their combination gives quite different results than simple polarisation - a lot of new colours. And I think it doesn't have to be any crystals to occur those beautiful colours. I think that after my short observations.
Best regards
Marek

Ernst Hippe · Post by **Ernst Hippe** » Sat Jul 24, 2010 9:12 am

Marek,

there is no basic difference between "simple" polarization and such whith a Lambda/4 plate and/or a retarder. It's only a question, how much the colours are shifted up the pol. colours' scale. If something shows dublefraction, it will appear bright or coloured e.g. with crossed pol.-filters. I use retarders myself, also called auxiliary objects, of different path differences.
According to my observations the coloured parts in your crustaceans seem to be only crystals or muscle fibres, let alone tiny sand particles. Please look for specimen whithout pol. colours and compare them.
I'm looking forward to your results and more pictures if possible.

Ernst

Marek Mis · Post by **Marek Mis** » Wed Jul 28, 2010 1:56 am

NileRed,
As I promised you, I'm enclosing two pictures presenting my set for photomicrography. This set is not comfortable but it allows taking photomicrographs. As you can see I had to build special construction to my microscope. In the second picture you can see the polarizer and retarders in common housing. If you have got any questions don't hesitate to ask me.
Regards
Marek