More diatoms

[Radazz]

Polarizer and analyzer removed really brightens up the phase contrast.
Green Interference filter on field lens improves contrast and color.
Saturation and contrast enhanced in photoshop elements
7 image stack
20x Ph1
Olympus BX40
Brighter image. (Wow!)

8 image stack
background removed in PSE
My new avatar.

Radazz

[GaryB]

Those colors are gorgeous, well done!

What type of green interference filter are you using? I'm not very familiar with other than standard filters and I've never used an interference type.

[Hobbyst46]

Those colors are gorgeous, well done!

What type of green interference filter are you using? I'm not very familiar with other than standard filters and I've never used an interference type.

In agreement with both compliment and first question of GaryB, may I elaborate on the question.

For convenience, I will call 546nm "green", although it might be slightly different figure.
An ideal bandpass "green" interference filter can only transmit green, say wavelength of 545-546nm, and block all other wavelengths.
A non ideal interference filter will transmit a broader portion, say only those within 540-550nm, and cutoff all the rest.
That is a distinct advantage of interference filters over the cheaper absorption filters, those transmit a much broader portion of the spectrum, say within 500-600nm, and cutoff all the rest - below and above. Peak transmittance will be at 546nm, but significant transmittance will cover from 500 to 600nm (all numbers are suggested, according to my experience).
Your photo displays a very wide spectrum. Red and blue can be there only if they were included in the filtered light that hit the specimen.
Was it not a bandpass filter?
Or, were the colors added in software?

[Radazz]

I’m guessing it’s a GIF at all. Looking at it obliquely, it looks a bit like the coating on a dvd, while looking through into the light is a sort of milky green. I got it on the field lens of one of the Nikon labophot2 scopes I got from the medical school. Fit the Olympus perfectly, so I appropriated it.
As you see, it really enhances Phase contrast.
As I say, I’m guessing
Radazz

[GaryB]

Wow, I just did a search on ebay and what you describe appears to be a GIF 550nm phase contrast. They seem to cost around $90 or so.
Olympus 45mm 550nm green phase contrast interference filter, Part # 43IF550W45

I'll need to see if there is a generic version for less.

https://m.ebay.com/itm/Olympus-45mm-Gre ... %7Ciid%3A1

[Radazz]

That looks like the one. Mine is not in a frame, and looks like two pieces of glass with the coating between them.

[Radazz]

Here’s one for a little less
https://www.ebay.com/itm/Olympus-Micros ... 3270665235

[Hobbyst46]

I searched the web to find the transmission spectrum of the Olympus 43IF550-W45 filter but could not find it.
However, Olympus brochures specify it as a filter to produce monochromatic light, of wavelength 550nm, which is exactly the way to improve contrast in phase contrast microscopy. It almost certainly transmits narrow band, say 550+/- 10nm, that is, green light, without blue or red.

[vasselle]

Bonjour
Très belles images
Cordialement seb