Leaf casts (Thanks Manfred!)

[Charles Krebs]

I want to thank Manfred ("seeman") for showing me something new to try on a very rainy Saturday afternoon. I admired his two recent posts of leaf casts made using nail varnish (nail polish).

I collected a few leaves, dried them off, and gave it a try. The first two are a Viburnum davidii leaf. The third shot is a Polystichum munitum ("Sword fern"). Amazing how much detail is observed in these "casts".
(First and third are DIC, second is oblique brightfield. All with 20X objective).

[arturoag75]

Charlie ,
the third one is incredible..nice
Arturo

[Pau]

Manfred and Charles: this is a very interesting technique, Can you explain (or link) the method?

[Mitch640]

Very nice for a first time Charles. The green cast is from DIC?

Pau, there is some information on Google about doing this. Essentially, you use a dry leaf, a live, fresh one is best. Then paint it with clear nail polish and allow to dry, but no longer than 20 minutes of so, or it will be hard to get off intact. The link I saw, said to use a piece of Scotch tape, folded over so to leave a small length of the sticky side showing. Use that part to stick to the nail polish to lift it from the leaf and transfer to the slide.

All our leaves are now under two feet of snow, so I can't do this till spring at best.

[john sp.]

These "casts" are indeed very interesting. I could see many innocent houseplants losing a leaf or two once one got started on this project. ;-)

Thanks for the additional details, Mitch, but I was left wondering if Charles and Manfred added water and a coverslip to the cast (or perhaps even some other fluid) in order to best view these specimens.

I suspect that they will be difficult to discern under standard brightfield conditions, alone; so some other lighting to enhance contrast will be necessary. (Charlie has illustrated the effectiveness of DIC and oblique illumination, and Manfred is likely using something other than brightfield, as well, I would guess.)

On the otherhand, I wonder if some color other than clear nail polish would give a thin enough cast that it would show well with brightfield and offer more contrast.

Anyway, I think these two have given many of us ample reason to think of trying something new.

John

[Charles Krebs]

The clear polish definitely needs some type of illumination contrast enhancement to bring out the details. I think Manfred showed in his first post that Rheinberg illumination could be very effective with this subject. (Not sure what he used on his second..oblique?).

[g4lab]

This is a variant of replication. These techniques are used in scanning and even in transmission electron microscopy and will preserve details into the size ranges of those techniques.

I believe the first method of doing this involved aqueous based solutions of poly vinyl alcohol (trade name Elvanol) which were allowed to dry out onto surfaces and then were lifted with tape. I did some of this in the early seventies when I worked at a Materials Research Lab. We were looking at fracture surfaces in the transmission electron microscope.

You then had to shadow the replica to render it electron opaque for the TEM, or conductive for the SEM. This could be done in a vacuum evaporator or a sputter coater.

The technique was also used extensively to replicate intracellular interior surface features, generated by the freeze fracture method. Blocks of tissue were frozen to liquid nitrogen or dry ice temp and put in a clever gadget that would fracture the frozen piece. The exposed surface was then replicated by a similar technique to above and the moisture vacuumed away without boiling. That would leave a replica with great detail. I never actually did this myself but did have the opportunity to admire TE micrographs from someone who did.

I don't know whether biologists still do much freeze fracturing since there are now confocal scopes available that seem to easily resolve self emitting things smaller than the usual resolution limits.

[BJ]

Hi,

i often play with this technique and keep saying that I will pursue it more systematically. Some leaves give nail polish peels a lot easier than others. We have a mediterranean climate here and a lot of the leaves are very hairy. Sometimes the polish just seems to soak into the hairs and it is impossible to remove a clean peel. Other times the polish pulls off the hairs - which can be interesting in its own right. With some leaves, i have got better peels by first cleaning gently with 95% ethanol. I have also got interesting peels sometimes from petals.

I have got excellent contrast using Rheinberg illumination (eg blue central "stop" with a red surround) and a really good 3D effect with darkfield. Unfortunately I am a lousy microphotographer, but if Charles will allow i could post two old rather out of focus photos in this thread to show the effects.

thank you to Charles and Manfred for interesting posts,
obrigado
Brian

[Charles Krebs]

Brian,

but if Charles will allow i could post two old rather out of focus photos in this thread to show the effects.

Please go ahead. I would like to see some more Rheinberg "renditions" of this subject.

[BJ]

Hi,

thank you to Charles fro allowing me to post in his thread, 3 rather poor photos:

1. nail varnish leaf peel (lower epidermis...?species). Rheinberg illumination, with blue central stop and red surround.


2. same peel with oblique/darkfield illumination ( on close inspection, I think with this photo, the dark stop was off centre (handheld) giving an extreme oblique illumination rather than darkfield)


3. peel of upper leaf epidermis of Pistacia lentiscus (mastic tree) showing a trichome pulled off the epidermis by the varnish.


microscope Olympus BX 40
achromat lenses
camera Canon A640

Apologies for the poor quality of the photos (now you know why I am too embarassed to post very often!) but I hope they are of interest.

regards
Brian

[john sp.]

Brian, looks like a line break got introduced into the url for the third photo. Maybe you can mend it back together (with delete or back space) and then see if the image displays on this page. [Fixed by Admin]

I think that your "failed" darkfield actually turned out just about right for capturing the details of this leaf cast. Thanks for jumping in and sharing your success with these types of specimens.

[Wim van Egmond]

Wonderful!!! It is a very nice trick for the holiday season. :-) I think it works best with oblique illumination and Rheinberg. It is made for Rheinberg! Also try using thin rings with different colours. http://www.microscopy-uk.org.uk/mag//ar ... nberg.html

And when you use blue and yellow (or orange) the image will look more like real leafs.

And, Hi to all!

Wim