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Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 12:54 am
by rnabholz
Maybe you all will like darkfield better than oblique? More fossil diatoms from St Laurent La Vernede.

American Optical 10, 100x Plan Achro Iris Oil, toric darkfield condenser, Canon 70D, captured in green light, converted to grayscale in post processing, stacks as noted, Zerene Stacker using the PMax process.
44µm  Stack of 6
44µm Stack of 6
St Laurent La Venede 9838-43 ZS PMax Final.jpg (52.99 KiB) Viewed 1796 times
44µm  Stack of 3
44µm Stack of 3
St Laurent La Venede 9835-37 ZS PMax Final.jpg (124.55 KiB) Viewed 1796 times
44µm Stack of 5
44µm Stack of 5
St Laurent La Venede 9830-34 ZS PMax Final.jpg (88.83 KiB) Viewed 1796 times
50µm Stack of 17
50µm Stack of 17
St Laurent La Venede 9844-60 ZS PMax Final.jpg (126.95 KiB) Viewed 1796 times

Re: Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 3:15 am
by zzffnn
Very nice work, Rod. Your oblique and darkfield images are both beautifully done. I think it is just that forum members still catching up with new posts.

Have you tried stacking circular oblique light mask? For some diatoms, COL works better than offset oblique.

DF is simply an oversized COL. Your DF works very well, so I am guessing COL may work nicely too. I am just curious.......

Re: Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 7:38 am
by Hobbyst46
Very nice images. Thanks for posting.

Re: Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 11:40 am
by rnabholz
zzffnn wrote: Have you tried stacking circular oblique light mask? For some diatoms, COL works better than offset oblique.

DF is simply an oversized COL. Your DF works very well, so I am guessing COL may work nicely too. I am just curious.......
Thanks zz

I have an interest in trying COL, but could use a reference on how to go about it. Any you can refer me to?

Re: Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 11:41 am
by rnabholz
Hobbyst46 wrote:Very nice images. Thanks for posting.
Thanks Hobby.

Re: Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 6:22 pm
by zzffnn
Rod,

Paul James did a 4 part write-up on COL before: http://www.microscopy-uk.org.uk/mag/ind ... pjcol.html

Using the right mask size and mask centration is key. To start, close down condenser iris to around 85% of objective NA, then vary mask sizes. When in doubt, try smaller mask; if illumination ring is too narrow (mask being too big), halo and shadow may be too severe (such that it would reduce resolution).Thick diatoms may require a slightly smaller mask size than thin diatoms.

Here is another article about COL by Ted Clarke: http://www.microscopy-uk.org.uk/mag/ind ... c-col.html

Re: Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 8:13 pm
by MicroBob
rnabholz wrote: fossil diatoms from St Laurent La Vernede
Hi Rod,
your nice images remind me that I have some cleaned material from this location that I still haved not looked at! The fall is coming soon and I hop to make some nice slides from it.

Bob

Re: Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 9:51 pm
by rnabholz
zzffnn wrote:Rod,

Paul James did a 4 part write-up on COL before: http://www.microscopy-uk.org.uk/mag/ind ... pjcol.html

Using the right mask size and mask centration is key. To start, close down condenser iris to around 85% of objective NA, then vary mask sizes. When in doubt, try smaller mask; if illumination ring is too narrow (mask being too big), halo and shadow may be too severe (such that it would reduce resolution).Thick diatoms may require a slightly smaller mask size than thin diatoms.

Here is another article about COL by Ted Clarke: http://www.microscopy-uk.org.uk/mag/ind ... c-col.html
Thanks zz.

Sounds a bit tricky to dial in. I'll look into it.

Re: Oo La La, More French Diatoms

Posted: Tue Sep 11, 2018 9:53 pm
by rnabholz
MicroBob wrote:
rnabholz wrote: fossil diatoms from St Laurent La Vernede
Hi Rod,
your nice images remind me that I have some cleaned material from this location that I still haved not looked at! The fall is coming soon and I hop to make some nice slides from it.

Bob
Thanks Bob.

My sample is very centric heavy, all sizes including some pretty big ones. There are some other forms scattered too, as you can see.

Good Luck with it.

Rod

Re: Oo La La, More French Diatoms

Posted: Thu Sep 13, 2018 12:12 am
by Charles
Beautiful Rod!

Re: Oo La La, More French Diatoms

Posted: Thu Sep 13, 2018 3:06 am
by rnabholz
Charles wrote:Beautiful Rod!
Thank you Charles!

Re: Oo La La, More French Diatoms

Posted: Wed Sep 19, 2018 7:44 pm
by vasselle
Bonjour
Superbes images