Poor man's DIC

bromodomain · Post by **bromodomain** » Sat Jul 16, 2011 2:32 am

Recently I got the opportunity to play with the DIC setup on a Zeiss Axioplan and I was utterly impressed. Too bad its so expensive

Could anyone sum up the reasons of why its so unaffordable?

Anyway I tried some experiments at home and oblique+partly crossed polars was the closest I could get to DIC (although still very far away from the actual technique).

This may not be the most representative shot but one can notice the high and low amplitudes on the opposite sides of this paracetamol crystal.

Any input on improving the oblique illumination is welcomed. It seems that there are many possibilities to experiment with oblique illumination and I was wondering whats the closest anyone has ever came to DIC?

Cactusdave · Post by **Cactusdave** » Sat Jul 16, 2011 2:48 am

It is possible to get very 'DIC-like' effects with forms of oblique illumination, alone and in combination with other contrast enhancing techniques such as Rheinberg illumination and partially crossed polars. These techniques work particularly well on transparent low contrast subjects. The problem is that compared with true DIC they are often very sensitive to minute changes in setup and therefore hard to reproduce consistently. See this thread and links contained in it http://www.photomacrography.net/forum/v ... ght=#87794 and the nice oblique illumination example in this recent post. http://www.photomacrography.net/forum/v ... highlight=

bromodomain · Post by **bromodomain** » Sat Jul 16, 2011 5:42 am

Excellent, thanks! Do you know why the equipment is so expensive? I feel like investing in DIC but it may take a while to save some cash.

Litonotus · Post by **Litonotus** » Sat Jul 16, 2011 9:31 am

thanks for pointing my examples (:

I have perfected my 'DIC-like' filters (: I may write a thing or two about them in couple of days.

the only inexpensive DIC is polish manufacturer's (PZO) system dedicated for their biolar micorscope, but it may also be used on other micorscopes - mostly chinese ones. many of amataur microscopists in Poland use hybrid systems, and they work well. this DIC set is about $600-700, and it is very cheap compared to all others.

one thing has to be said here - this DIC system is a very good quality one (look at ChrisM's photos). communists made the great polish manufacturer fell... we would have the great 5 today.

Cactusdave · Post by **Cactusdave** » Sat Jul 16, 2011 10:56 am

Chris_M's DIC pictures with the PZO DIC system are certainly very good. No doubt about that.

http://www.photomacrography.net/forum/v ... hlight=pzo
Unfortunately the PZO system doesn't seem to be widely available outside Poland and the few I've seen on Ebay were actually being offered for a dollar price higher than the equivalent you quote in Euros. I guess English operating instructions might be an issue also. Perhaps our Polish friends on the forum could put something in the Equipment section on the PZO DIC system? I'd like to know more about it and how it has been fitted to non-PZO microscopes.

Litonotus · Post by **Litonotus** » Sat Jul 16, 2011 11:32 am

It is extremely rare on a ebay (I saw one offer - very expensive one), it should be bought on polish allegro online auctions. It is offered from time to time for $600-700. If anyone from abroad is seriously interested and the set is listed on allegro - buying and shipping could be arranged (:

full set includes objectives, but those objectives are not for DIC, and you do not need them. you have to find a set without objectives and it costs - as I said - $600-700.

the PZO system consists of 3 parts: polarizer, condenser and the head (prisms and analyzer are inside).

to fix it on other than biolar micorscope two things has tobe done:
- the PZO condenser mounting diameter has to be changed from 39mm to 37mm to fix it on chinese microscopes.
- second thing is to adapt the microscope base and head to place the dic module between them. that's all. here is a link to a picture of how it looks like: http://www.forum.biolog.pl/resources/image/3855 (one of polish forum member's set)

No one of us registered here has such hybrid (ChrisM has biolar microscope, Marek has CZJ, and I have a Motic scope). I can only say what the others have succesfully done. I wanted to get that system to make such a hybrid too but I changed my mind and I want to get something better in (long) future.

bromodomain · Post by **bromodomain** » Sat Jul 16, 2011 3:33 pm

Are there any non-oblique based alternatives to DIC? Whats the deal with plasDIC?

Perl · Post by **Perl** » Sun Jul 17, 2011 12:49 am

Hi

Take a look at this - Complete set

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... :MESELX:IT

Regards
Pär

Cactusdave · Post by **Cactusdave** » Sun Jul 17, 2011 1:20 am

PlasDIC was introduced in 2004 by Zeiss to get around the problem of the birefringence of polystyrene tissue culture vessels destroying normal DIC, but is still based on Nomarski's principles. http://www.zeiss.de/C12567BE00472A5C/Em ... arch_e.pdf
Nikon and Olympus also introduced a system which worked through plastic based on Hoffman modulation contrast, which is a kind of combination of oblique illumination with polarising effects as I understand it. http://www.nikoninstruments.com/Informa ... n-Contrast
Both of these systems introduced an additional slit into the light path. I don't pretend to understand the optical physics involved, but clearly they work. The article in the first link is deeply impenetrable to me

. I don't know about the current cost of these systems, which still require specialised components. I don't know any 'amateur' who has one. You might be interested in this old thread on the Yahoo Microscopy Group that discusses PlasDIC and members' attempts at 'do it yourself' duplication of its effects. http://tech.groups.yahoo.com/group/Micr ... sage/13755

Ecki · Post by **Ecki** » Sun Jul 17, 2011 11:48 am

The light path in Nomarski DIC: polarizer -> Wollaston prism -> object plane -> objective -> Wollaston prism -> analyser.

The light path in PlasDIC: slit diaphragm -> object plane -> objective -> polarizer -> Wollaston prism -> analyser.

It is cheaper to build because you can use standard objectives and only one Wollaston prism is required. It is cheaper to use as polystyrene petri dishes can be used - normal DIC is killed by the birefringence of polystyrene.

But beware, the PlasDIC image is monochrome!

g4lab · Post by **g4lab** » Sun Jul 17, 2011 5:37 pm

Zeiss also has something similar called TIC which is for incident light use.
http://www.zeiss.com/C1256F8500454979/0 ... 6_0019.pdf

http://www.zeiss.de/C1256D18002CC306/0/ ... 0018_e.pdf

bromodomain · Post by **bromodomain** » Mon Aug 08, 2011 5:35 pm

Jan l'Amie · Post by **Jan l'Amie** » Mon Aug 08, 2011 11:58 pm

Bromodomain, I don't know how you made these photo's but I got the same effect with my home-made Kreutz filter. This filter you can make in a couple of minuts, costs less then 2 euro's.

http://www.photomacrography.net/forum/v ... hp?t=14154

Litonotus · Post by **Litonotus** » Tue Aug 09, 2011 3:25 am

the first one is broken glass, isn't it? it looks like obligue light mixed with advanced rheinberg ilumination - looks great and may be very cheaply done indeed (:

bromodomain · Post by **bromodomain** » Tue Aug 09, 2011 6:35 am

The filter costs absolutely nothing. Just a piece of carton from a cereal box. The primary polarizer is a piece of LCD screen plastic and the analyzer is a linear Zeiss polarizer that I placed above the objective turret. I used a concave mirror and situated the filter orthogonally to the microscope light train. Basically it was blocking the light in front of the mirror. There is potential in this oblique business but its hard to replicate it. For something that costs me nothing I think its OK $\:D/$

As for the crystals themselves its a random mixture of 0.21% Bromophenol Blue, 0.21% Xylene Cyanol FF, 0.2 M EDTA, pH 8.0 and 50% Glycerol (or simply DNA loading buffer) with paracetamol a bit of vit. C and some citrate and probably urea.

Poor man's DIC

Poor man's DIC

DIC Set