Best specimens for testing DIC?

[Dubious]

I am just getting started with DIC. I obtained the DIC parts for my Olympus IMT-2 and am trying to set things up right and test whether DIC is working properly. I don't have the manual for the DIC kit for the IMT-2, so am winging it. Does anyone have any suggestions as to readily-available available samples or specimens that would work best for the testing? I am getting what I think are weak DIC-like effects with some prepared slides I had on hand, but they are stained slides and probably not very good subjects. I will soon have some glass-bottomed petri dishes (was using plastic) so can move to protists, but specimens that stay still would be easier to compare.

Thanks for any suggestions.

[viktor j nilsson]

Small oil droplets can be a really good test subject that really reveals if you are getting proper DIC.

[PeteM]

A bit of saliva pushed down under a cover slip is another easy specimen. Even more interesting with a bit of soap and oil.

[75RR]

Small oil droplets can be a really good test subject that really reveals if you are getting proper DIC.

That seems very useful for those setting up DIC for the first time or experimenting with alternative ways to achieve DIC.

Have you by any chance some before and after images - I am sure they will be instructive.

[Dubious]

Thanks, exactly what I needed! Here are the results. I used the 20x objective for the following photos, although the camera port crops so much it's more like a 40x FOV. Note that the IMT-2 is an inverted microscope, so the view for these is up through the slide. Photos are unedited and I tried to keep the before and after as similar as possible, although I did tweak the focus a bit for 1B for those twin "hills" that DIC had made more prominent. So, what is the verdict?

1A - saliva under slip cover, Brightfield:


1B - saliva under slip cover, DIC:


2A - saliva with oil and soap under slip cover, Brightfield:


2B - saliva with oil and soap under slip cover, DIC:


3A - small drop of oil, no slip cover, Brightfield:


3B - small drip of oil, no slip cover, DIC:

[LouiseScot]

I'm kindof in the same boat as I've been trying to put together a dic setup. It can be quite hard to tell if it's really working (or not!). Is what I'm seeing true dic or a trick of the light, or oblique illumination? The oblique illuminated paramecium video (in pictures and videos) could almost pass for dic - it's very good! Viktor's suggestion of oil drops is one to bear in mind Also, Nikon hosts a useful dic gallery: https://www.microscopyu.com/galleries/d ... e-contrast

Louise

[Dubious]

Thanks, the before/after photos on that site are useful--I may try cheek cells...
Yeah, it is tricky. With phase, at least you can tell by the bright halos that it's working.
I think I probably am getting DIC but just don't have enough experience with it to be sure. Also, because I don't have the DIC manual and my setup does not allow some of the setup procedures I have seen described in other manuals, I'm probably not adjusting things right.
Some of those oblique images do seem the equal of DIC, all right. One interesting thing I discovered since posting the above photos is that I can get results almost, but not quite, as good as DIC (if that is what it is), by using just the polarizer and slider/analyzer and closing down the aperture iris a bit more. That is, I switch the condenser to brightfield but leave everything else in place.

[eKretz2]

Your 1A and 1B images already have cheek cells. The ones that look sort of like a fried egg. And yes I would say you're getting DIC in 1B - cheek cells show it pretty well.

[Dubious]

Hey, I never thought of that, but that is where the saliva came from. Thanks!

[eKretz2]

Here are a couple to compare with, both are EPI DIC of cheek cells. One with a cover slip and one without. (EPI does not generally work great with a cover slip). The non cover slip is dried out from evaporation.

Without cover slip, 50x objective


With cover slip, 50x objective

[Dubious]

Thanks, eKretz2. Meanwhile, here is a vorticella--again, looking up through a slide. Not a great photo but interesting and it does look like DIC, given the "3d surface" features. I wish I could do something to get more color--everything seems very monotone.

[tpruuden]

Thanks, eKretz2. Meanwhile, here is a vorticella--again, looking up through a slide. Not a great photo but interesting and it does look like DIC, given the "3d surface" features. I wish I could do something to get more color--everything seems very monotone.

Waveplate for more color - minimally a thin plastic film in light path.

[rudnicki]

Oblique lighting is not difficult