Darkfield Sunflower stem

[mrsonchus]

Hi all, I've been slide-surfing and though I'd try to make darkfield with the x2.5 Leitz objective. I used a piece of Blu-Tack squashed into a diffusing-filter slipped into the filter tray beneath the condenser, top lens swung out.

Anyway it's interesting to see and I may well give it a try with a more accurately set stop, perhaps on live tissue too such as pollen grains.

Thought you may like to see the result, quite nice really - this was/is a stained and permanently-mounted slide of a Sunflower axial-branch stem in TS, sectioned at 10µ and mounted in Numount resinous mountant. The stains are Safranin and Fast-green, although of course this view is not the usual 'look'...

ws_darkfield-sunflower-stem.jpg (398.42 KiB) Viewed 9442 times

May try a few more.

John B.

[Crater Eddie]

Very interesting... and somewhat haunting. More please!
CE

[JimT]

Very very good and yes, more. Really brings out the detail.

I have also done some dark field images of transverse sections (Not as good as this one) and based on your good results I will have to try some more.

Looks like that 2.5X obj. was a good acquisition.

[billbillt]

I love this look!... Your usual perfect job and presentation...

BillT

[Hobbyst46]

Beautiful!

[billbillt]

.

[KurtM]

That's a really pretty image, looks like an entry in one of those contests to me!

[mrsonchus]

Very interesting... and somewhat haunting. More please!
CE

Thanks Ed' - yes, if I glance sideways at it it reminds me of one of those 'big round space-entities' coming towards the Starship Enterprise - the original of course!

[mrsonchus]

Very very good and yes, more. Really brings out the detail.

I have also done some dark field images of transverse sections (Not as good as this one) and based on your good results I will have to try some more.

Looks like that 2.5X obj. was a good acquisition.

Hi Jim, good to hear from you!

Yes, I was really surprised that a decent image came out - quite pleased!

The two major factors seem to be the edge of the stop is in focus with the specimen, and that the stop is the right size of course.
The 100W bulb I have in the Orthoplan at the moment easily gave me the high light-level needed to get the image this bright with the field jet-black.

Yes, I'm very pleased with the x2.5 indeed! Thanks Jim.

[mrsonchus]

I love this look!... Your usual perfect job and presentation...

BillT

Hi Bill - thanks my friend - yes I found the look really pleasing too - seems so finely detailed.

p.s. I like the look of the new objective - get it in the turret! I'd love to see how it perform for you.

[mrsonchus]

That's a really pretty image, looks like an entry in one of those contests to me!

Haha! Thanks Kurt, yes it's quite an eye-candy affair this darkfield stuff - great tissue delineation between the epidermal, the cortical, vascular and ground systems - really clearly visible in the overview. Must try some more of this technique perhaps with some better cut-out stops.

Thanks Kurt.

[charlie g]

Beautiful colors, Mr.Sonchus. I love the blue coloration, like a stained glass window to my eyes. Terrific anatomy on a dark winters night! Charlie guevara

[einman]

Very nice indeed

[vasselle]

Bonjour
Superbe image

[mrsonchus]

Bonjour
Superbe image

Thanks Seb - pleased you like it.

[apochronaut]

I can't remember, John; if you have phase on your Leitz? If you have, the phase annulus for the 100X objective, makes a good DF stop for low power objectives, 10X and under. The 40X annulus can be used for very low power objectives. They are nicely centerable too.

nice image.

[photomicro]

I can't remember, John; if you have phase on your Leitz? If you have, the phase annulus for the 100X objective, makes a good DF stop for low power objectives, 10X and under. The 40X annulus can be used for very low power objectives. They are nicely centerable too.

nice image.

Great minds think alike eh John? Quite ironic.

Sometimes a similar (but different!) effect can be achieved with polars.

[JimT]

Sometimes a similar (but different!) effect can be achieved with polars.

Ah yes. Plant sections in polarized light can be enjoyable as well as very revealing of hidden details.

[billben74]

I like it. A lot.
Fabulous image. Now where is my dark filed condenser.....

[mrsonchus]

Hi, yes the polariser is great for lignin, the xylem secondary lignified cell walls glow!

Here are a couple of examples of polarised xylem lignin,

Compared to 'normal' brightfield,

ws_brighfield_polarized.jpg (161.65 KiB) Viewed 9087 times

Looking down into a vessel with polariser,

ws_xylem_polarized_birefringence.jpg (30.17 KiB) Viewed 9087 times

Should be able to get the big-O up & running soon with the new 402a rig!
I'll post a heap of images as I put it through it's paces.
Of course the 402a alsohas a darkfield stop which should be interesting to try on perhaps some moss parts and pollen grains....

Back soon...

[mrsonchus]

I can't remember, John; if you have phase on your Leitz? If you have, the phase annulus for the 100X objective, makes a good DF stop for low power objectives, 10X and under. The 40X annulus can be used for very low power objectives. They are nicely centerable too.

nice image.

I just bought a 402a Apo' - and it's just arrived, as have x10, x25 and x40 Phaco objectives to go with it - just waiting for the adjuster wrenches to arrive although I'm improvising a little with a pair of fine forceps to a reasonable extent as a starter...

Thanks Apo'

[charlie g]

Your first df image stunning, Mr.Sonchus..like a peek at Louvre, France stained glass windows. thanks for these df contrast method colors. Charlie guevara