🔬 Making microscope filters: Darkfield, Rheinberg, Oblique

If your microscope has a condenser with a filter holder, then you can try to make filters and patch stops. These will change the colors of the specimen quite dramatically.
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[@GrzegorzBaranArt]

Hey Olivier, just wanted to tell you that what you say about the blue filter isnt correct. The main function of the blue filter is to get sharper image (higher image resolution) and reduce effect of light diffraction. It is because the wave length of the light perceived by human is between 400nm and 700nm. 400nm is blue while 700 nm is red. It means that the wave length of the red light which is around 700nm is almost two times longer to the shortest wave length human can perceive. Using the shorter wavelength can make a big difference when we deal with very high magnification levels. Just saying since I study color since years now and thought you might find it useful.. unless you already found it in a future as this video is 3 years old :). Thank you for all great job you do with your videos. They are really super helpful and I love them all. Cheers!

[@Baji_drawings]

You are correct but he doesn’t mean that

[@stefanidno]

This is fantastic, thank you! I'd love to see more videos about small modifications/different techniques like this!

[@Robodie]

Love your channel - content that's actually useful, clear explanations of why and what you're showing, comparisons (including failed / mistakes / less effective), all the details. Just wanted to let you know that you are appreciated!

[@dorsetdumpling5387]

If you want to use glass, you can find 32mm (or just about any sized) watch glasses really cheaply on Amazon. I got 10 glasses, 32mm by 1mm thick for less than £5! They fit perfectly in my filter holder.

[@davewinch7677]

I just made a dark field filter for my microscope. For the dark spot, I stuck some black electrical tape on the bottom of a triple A battery, for a pattern, then cut around that with scissors, peeled it off and stuck that on my clear plastic disk. Works great, thank you for the information.

[@dennisfreeman9761]

Thank you, Oliver! I am very interested in DIY modifications like this for photography. Your experimental findings about Rheinberg filter color density was very instructive.

[@urbansnipe]

using adhesive vinyl (can be opaque or transparent with colour) or even using insulation tape would be quite effective. even those tins of chocolates have a very good variation in colour films that wrap the chocolates you could sandwich them between two filter lenses with ease. just a suggestion :) im still choosing which microscope to get i had one as a child years ago which since has vanished :(

[@bendirval3612]

Do you have a pdf or image file of the filters as you printed them out?

[@LinasJu]

Really well put, with so much practical information. Oliver, this technical channel of yours is a gold mine.

[@Mitch.Wasserman]

You're videos are so expertly done. Thank you for sharing all of your valuable knowledge and expertise.

[@teresashinkansen9402]

A disk of tin foil might work as well to make the light stop totally opaque just glue it into the glass disk and paint it with a sharpie so it isn't reflective.

[@jarmengolalbanell]

Coins of different diameter, painted

[@theunseen010]

Unfortunately, I dropped and broke my blue filter that came with my microscope in half while taking it out of the box in excitement.. I found your resources and used some tinfoil, sharpie marker, and scotch tape to both repair the blue light filter and turn it into a dark field patch stop. It looks amazing, but I had to change the size of the center 3 times before it performed correctly... My microscope has the swing-out filter holder and I can get some of the oblique illumination effects with the dark field stop I made and swinging the filter holder in and out! Thanks again for the awesome resources! You're the best!

[@Baji_drawings]

I tried it and felt great. Thank you for your input

[@evanthompson116]

Man every time I get an idea to save money I see you already done it happy to see it works thank you for the video

[@MarieChardome]

😂

[@glikar1]

Fabulous, thank you! You've provided the answers I was looking for.

[@darkskyatnight]

Very concise and easy to understand!

[@bendirval3612]

Seems like for many microscopes, instead of darkfield being a filter, it's a whole different condenser. Not very convenient for this type of experimentation--not really that convenient in general since swapping out condensers is a lot more of a hassle than just swapping filters. Are darkfield condensers inherently better in some way?

[@MicrobehunterMicroscopy]

There are different dark field condensers, more elaborate ones have internal concave mirrors that redirect the light (expensive). Not automatically better, but some are designed to work also with high numerical aperture (ie high magnification) objectives and a simple filter works up to 20x. With 40x I already have some problems with a filter (too dark, blurry).

[@japrogramer]

Have you tried a filter with a dark center but different colors around the edge. Could be interesting to see the effect of rotating the filter.

[@sabyasachibanerjee124]

Very useful! I'm gonna try this out

[@boris2342]

I can watch your vids for hours

[@rsk6929]

I can see how excited you are. Thanks for sharing that excitement along with the info keep it up! Science is fun

[@microscopedope4017]

Oh wow. I was about ready to a few hundred on a dark field condenser cause I thought it was the only way to do dark field 😬 Thanks for the video 😁

[@BHFWaterloo]

can you place the patch stop right on top of the Kohler illuminator if you don't have a filter holder

[@gregvisioninfosoft]

silkscreen and photo etching, similar to circuit board making, would be my choice for producing one offs. or for thicker material water jet cutting.

[@Mark-ks9jj]

LED and halogen filament are both small point sources of illumination. I think better dispersion of the led light would improve the side illumination say with a prismatic lens. Great instructional video btw as usual excellent and easy to follow information well done

[@bradxwx]

i've found your videos to be one of the best resources shopping for a microscope. hard shopping for something you know little about

[@ahmetkaracaoglu5617]

Awesome.Thanks...

[@theleadlifereloading5742]

I bought clear acetate sheets today from a craft store for $2.60. I am going to use cardboard, and colored markers to make a variety of filters for relatively free of cost. Your thoughts?

[@diegoroberto8339]

Fantástico!!!

[@davidcalderon2016]

Estaba esperando un vídeo sobre este tema!! Gracias, estaré pendiente de los siguientes!! Saludos desde Guatemala!!

[@DaveFer]

Love your channel. Thank you for your generous contribution of time in making these videos. I'd like to suggest a topic for a video if you haven't already done it: A video on how to clean slides and what to expect from new slides from a box. We just got a very nice stereo microscope for the kids. But the biggest problem I have encountered is that the slides / covers that were included with the scope are absolutely horribly corrupt right out of the box, handled with much care. There are many different types of corruptions: flaw / bubbles in the glass, foreign matter on the glass, scratches, etc. It's almost as if they included recycled, poorly cleaned slides. I won't mention the company because I LOVE the scope. But would be very valuable for us to see a video on how to clean slides and covers. Best wishes!

[@MicrobehunterMicroscopy]

I have to agree that many new glass slides and cover glasses look horrible right out of the box, sometimes even unusable. I have to clean them before use, and sometimes even this is difficult. Sometimes there are water spots on them. I suggest putting them into vinegar for a few minutes, which will remove the calcium carbonate deposits from the water spots and other things. Then rinse with soap and warm water. Sometimes dry-wiping the slide with a microfiber cloth works, but it depends on the type of dirt. Sometimes these are not scratches that you see (unlikely on glass) but rather fatty deposits from the manufacturing process, which are hard to remove.

[@arvetis]

My microscope's manufacturer sells a specific "darkfield condenser" for a hundred bucks. Why do they do that if I can just use a patch stop?

[@betodruid4422]

This will be extremely helpfull for me, thank you !

[@sanaanasr9877]

Very useful. Thanks for sharing. Which filter would be best to observe live bacteria? Thanks.

[@jacobmarvel395]

Is that the Tyndall effect you are talking about?

[@robertYTB78g]

Excellent and interesting video, can't wait to try it out :) thanks for posting

[@edward_grabczewski]

Darkfield seems to have two interpretations: the first is the one shown here using a filter disk; the second seems to be a ring of light shone through the objective lens itself. Olympus has objective lenses that do this. I guess as long as there's a dark background surrounded by a ring of light then it gives the same effect but the first method shines light through the bottom of the specimen and the second from the top. This must surely give very different views.

[@MicrobehunterMicroscopy]

The system where the light comes from the top does give a different impression. It is epi-illumination. There are also darkfield condensers which contain a concave mirror that reflects the light coming from the bottom.

[@edward_grabczewski]

@@MicrobehunterMicroscopy On the Olympus website they have a few articles on darkfield. Here's a reflected darkfield article: www.olympus-lifescience.com/en/microscope-resource/primer/techniques/darkfieldreflect/ and here are the rest: www.olympus-lifescience.com/en/microscope-resource/primer/techniques/darkfieldindex/

[@hebintn]

Some of these samples/ images would be striking with stacking several images at different focal lengths. Have you done any experiments with stacking? It's more computer oriented than microscope, but would be fun. I have not tried stacking but it's on my to-do list.

[@andrewmiller6672]

Do you just use extension tubes and a c mount adapter for dslr/mirrorless recordings? I heard the Amscope multiplier ef to c is really soft. Wondering if anybody has tried any other type of magnifiers out there?

[@abid0296]

i learn so much from watching your video...thank you

[@NoName-ow9de]

I love it! Cheap and easy!

[@karl3549]

One may also be able to utilize a 3D Printer in order to make some interesting filters. I'm not sure at what temperature the halogen bulbs operate (if I had one, I'd put a temperature probe on it and see), so one may have to print the filters with ABS, PETG or another plastic which has a higher melting point than PLA.

[@MicrobehunterMicroscopy]

Yes, and I also have tried this in the following video: kzbin.info/www/bejne/bJnLZo2viphor8U

[@karl3549]

@@MicrobehunterMicroscopy That's great! I just found your channel recently so I'm still going through all of your videos. Thanks for the link!

[@elenaacim]

Beautifully done! 👍

[@PawelGrzelak]

Thank you very much

[@yeraydavidsquicciarinigati1574]

you explain evreythin do great i love to see your videos

[@RichAT]

Do you have a formula or a plan that guide you in the size of the inner darker circle in your homemade filters?

[@florisklein536]

I got a Leica DM300, which set of filters do you recommend (I mainly will use it for mycology purposes) thank you in advance

[@user-mn9ob8he7z]

Hi for all of these last images specially the one you said you had no filters (~min 17:24/21:21 ), you still had the blue filter in and then added additional filters to it for the additional images. I ask because my microscope the image is reddish/ yellow and its difficult to get the contrast of the samples (single layer transition metal dichalcogenides, opaque sample)

[@ALIPHD5]

Great explanation thx .

[@lotharmayring6063]

why do u not make phase contrast filters

[@aminkakar2347]

Very good video, thanks Sir for increasing my knowledge but one request could you upload videos without music in background? Because I don't like music.

[@rcpd3359]

Would it be at all possible to add a or make a dark field filter for the telmu microscope or no ? If so how would I do that?

[@Finley0312]

Can you recommend a darkfield filter holder and replacement objective lenses for an old Swift International colligate microscope? Model number #75E6020 M220-400 series. Thank you!

[@starsoffyre]

For single LEDs, placing a fly-eye lens over the light source should do the trick

[@The.Chiefman]

Thanks for this great information

[@minhkhoalecong6334]

DO you have the dimensions for the blocker? Thank you!

[@jessemangiardi7308]

Can you post a link to a commercial darkfield patch stop like the metal one you show? I cannot find one on Olympus' site or elsewhere.

[@MicrobehunterMicroscopy]

It is not manufactured anymore by Olympus and the dark field patch stop sizes depend on the size of the filter holder. I think that it is best to make them yourself and experiment. I have also 3D printed some and they work well.

[@BLUE-ZONE-TEAM]

Nice really, do you have any idea about inverted microscope to convert dark field or phase contrast?

[@Simonjose7258]

What is 1.27k ? What # is that supposed to be? 127,000!? Or 1,270? Or 1,027?

[@MicrobehunterMicroscopy]

Are you referring to the number of subscribers? 1.27k is an abbreviation for 1270. The "k" stands for "kilo" which is one thousand. The dot "." is a decimal point and not a separator (different in different countries).

[@WenRolland]

Thanks for this, very interesting. :)

[@notyah2411]

What magnification do you use the most in your videos. My Brunel microscope is 10x60 at it highest.

[@MicrobehunterMicroscopy]

Max magnification of my objective is 60x. Rarely 100x oil.

[@usernamemykel]

SUPERB (as usual).

[@jamescorbin5638]

Great video. Very informative!

[@MicrobehunterMicroscopy]

Glad it was helpful!

[@Coopercup]

Thank you very much for your very good videos! If this works that good, so why is a separate darkfield condenser so expensive? Is it much better?

[@theredmonkey236]

Yeah I’m curious about the same thing

[@Yash-Gaikwad]

What is the diameter of this circles?

[@brapro8742]

Thanks so much, that's amazing!!! Do you have tried it for Stereomicroscopes? They don't have a condenser and I don't know exactly if that would work. I'll try it in any case. Thanks :)

[@MicrobehunterMicroscopy]

For stereo microscopes this does not work the same way, because the light is from the top. You can get a similar result by putting the specimen on a black background and then have the light from the top. This will also produce bright specimens on a dark background.

[@brapro8742]

@@MicrobehunterMicroscopy Thank you!!!

[@MarieChardome]

so, i could try a tube with filter in front of my top illumination or epilight, in a dark room 🤔

[@pinkpanther5379]

Are these filters able to be used in inverted microscopes also?

[@MicrobehunterMicroscopy]

if the microscope has a filter holder, one might be able to make it work, but the condenser is farther away from the objective so I can imagine that the dimensions of the filters have to be different.

[@michaelb.1860]

With the traditional long working distance condensers on an inverted scope darkfield is not possible - as microbehunter said, the condenser is too far away to get a darkfield angle...some higher end inverted microscopes allow you to use an adapter to mount a condenser from an upright microscope which then would allow you to do darkfield (no light path difference between upright/inverted at that point) but that is quite expensive even for research labs - more so than the cost of an entire upright microscope with darkfield

[@AlexanderDinchev]

Very useful video! Thank you! You are making really nice educational series! And I have a question about the condenser - Can a DarkField filter be used with an Abe condenser or it's necessary to install a different type of condenser in order to observe samples in a DarkField? I'm asking this because some microscopes require to replace the Abe condenser with a Phase Contrast condenser in order to use a DarkField illumination which is not clear to me why.

[@MicrobehunterMicroscopy]

A regular Abbe Condenser can be used for darkfield. This is what I have. You do not need a phase contrast condenser. But a Phase Contrast condenser can work also as darkfield. In this case the phase annuli in the Phase Contrast condenser take the role of the Darkfield filters. You can also buy dedicated darkfield condensers (rare), and in most cases not necessary.

[@AlexanderDinchev]

Thank you Oliver for your prompt reply!

[@Redpulsar2011]

Thank you!!

[@MiguelAngelRodzEcoguerrero]

You are a superman!! Woooww incredible work! greetings from mexico!

[@mhamado.abdullah6925]

Thank you 😍😍

[@TheJulioChaul]

man, you are the best

[@Nice2Much]

9:11 … I am an astronomer and if you touch my optical surfaces like that i would probably kill you !!!! 😂

[@borisgrejcha7263]

Hello! Please tell me will the Olympus CXH41 fit?

[@MicrobehunterMicroscopy]

If you have an Olympus microscope, then I would order the Dark field filter directly from Olympus and then use the dimensions of this filter to make others.

[@toucanjoe3302]

I have a celestron lab cm 2000 Cf, it has problem with the light ,is bluish all the time and in photos come intense blu .Anyone knows why?

[@MicrobehunterMicroscopy]

A slight blue tint can be a white balance issue with the camera (set it to automatic white balance) if the blue color is visible also from the lamp before it wen through any filters, then this could be that one of the colors of the LEDs failed (if you have LED). Or you can remove the filters. A blue filter is necessary for halogen lamps, but not LEDs.

[@toucanjoe3302]

@@MicrobehunterMicroscopy the blue is light looking with the eye but in photo is really strong.I think that I understood the problem, there is a permanent blue opaque lent in the illuminator but the light is a led so is a problem with this microscope model.i think the reason is because the celestron use to make this model with halogen light( and in the celestron website still say is halogen light )but then they changed with led without changing the illuminator.what do you think?

[@LabExperiment]

it won't work in high magnification how to make it works in higher magnification? answer please .. . . Iam from Indonesia

[@MicrobehunterMicroscopy]

You have to make the central disk larger. Watch this: kzbin.info/www/bejne/bJnLZo2viphor8U

[@LabExperiment]

@@MicrobehunterMicroscopy do you sell the darkfielf filter sir?

[@gr4653]

Спасибо! Огромное спасибо!

[@matthewbeard9035]

Great video thanks for you explanation. I’d like to encourage my children in science currently we have access to a 4- 10- 40 middle school type microscope I want something better. Can you recommend a couple for us that won’t make me have to work overtime. They are going to need to last from 4th to at least 12 grade. I’d like to encourage my daughters desire to be a doctor or research scientist. Please offer suggestions.

[@matthewbeard9035]

Oh and my son is also an Oliver

[@MicrobehunterMicroscopy]

If it is up to grade 12, then I recommend one with a condenser. Try the Swift SW350B or similar. Many microscopes in that range have very similar features anyway.

[@ixamraxi]

Looks like my laser cutter is going to get some use pretty soon :D

[@ceilingfun2182]

Does this work with sw380T?

[@MicrobehunterMicroscopy]

Yes, I already made videos on this topic.

[@AshwiniKumar]

why don't you start selling them, people would be interested in buying them :)

[@dorsetdumpling5387]

Has anyone tried this with an led light source?

[@gatotacha]

Excelente...muchísimas gracias

[@elfishendri873]

Thx

[@limchai8404]

really amazing, learn something

[@israelramos7441]

A poor's DIC.. 🤭🤭 thanks a lot!!!

[@vaulthunter3056]

very cool!

[@OksOksanium]

What's the purpose for filters with colored nested circles red-yellow-blue-black? kzbin.info/www/bejne/hpzYZYduqJJjosk

[@MicrobehunterMicroscopy]

I was simply experimenting, it is a variation of Rheinberg. But these filters will result in a mix of colors (two circles resulting in one color under the microscope), so the effect is not high.

[@ti62bu54]

great.

[@rajiv9144]

5:18

[@mothman_slayer4217]

It’s absolute bs that simple parts for a microscope cost sooooo much money 😡

[@miguelelento5637]

the oblique illumination was extremely dark almost don't see anything so I blame my light source.

[@theunseen010]

My light source has some kind of diffraction liquid over a single LED.. maybe you can use some foggy liquid solution (sealed of course!) in between the light source and sample to break up the point source into more of a cone?

[@benibuntu2052]

❤❤❤ ⚘️🌷⚘️🙏🙏😊😊😊👍👍👍

[@miguelelento5637]

:D

[@surajradhakrishnan2414]

Plz come to the point fast...you are so lagging and it's become bored over time