I believe that, if we can shoot good B&W pictures of knots, we should prefer them from colour pictures.
Colour pictures offer this easy, comfortable but also superficial, skin-deep only “similarity” with the real, familial everyday objects, but they lack the power of abstraction of black&white pictures. A picture of an object is NOT the object itself - it is just a f… picture ! A picture of a pipe, is not the pipe ! 
A picture of a knot, is not the knot - the knot is what you get when you entangle a piece of rope, and you pull, twist, untie, and then tie it again and again. A B&W picture helps us avoid the trap of “virtual reality” …
However, to shoot a good B&W picture is a difficult job : it requires effort, time, talent, equipment - and oftentimes luck…
That is why sometimes I feel the need to post those mediocre colour pictures ( which may look OK to most people ), AND, side by side to them, those mediocre B&W pictures ( which do not look as good as they should to me ! ).
Having said that, I would appreciate a generous offer of 7.450 $, to buy a Leica Monochrome :
http://us.leica-camera.com/Photography/Leica-M/LEICA-M-MONOCHROM2/Details
http://www.adorama.com/LCM246.html
Some nice B&W pictures :
https://instagram.com/jasonmpeterson/
We do not need to represent knots by pictures of knots tied on ropes : we can use other flexible “tubes”, made by various elastic materials, provided the do not elongate longitudinally, and they retain their circular cross sections. I have used vacuum cleaner and garden flexible hoses. as well as less wide steel springs ( steel is reflective, so it “writes” nicely on high contrast B&W pictures ).
To get an idea of what I mean, see :
http://www.tonyhutchings.co.uk/stilllife.html#23
Hi Xarax!
very nice!
I sometimes use “spaghetti” (boiled!) or, even better, “bucatini” and it’s funny too!
I have to shoot some B&W pictures 
ciao,
s.
A little off topic, but, I’ve wanted to purchase half-black & half-white (lengthwise) 5-7mm accessory cord with the express purpose of studying knot torsion signatures. I doubt that such a cord exists off-the-shelf, but I’d love to get my hands on some, and so not have to resort to jerry-rigging. It has long puzzled me the little “airtime” which torsion receives on this forum when it is such a deeply intrinsic part of what makes up a knot.
+1
Perhaps because the generation of torsion, during the shrinking of the nub, as well as the consequences of its “propagation” along a “twisted” segment, are effects which are veeery difficult to watch, to measure and to evaluate. I suspect that the differences we see in the shape of knots tied on stiff ropes ( which, among other things, “work” as torsion bars ) and on “soft” ropes ( which are not “loaded” by torsion forces ) are mainly due to the effects of torsion.
P.S. In general, kermantle ropes are stiff ropes, while single braided ropes are soft ropes. I am talking about the “resistance” of a segment of a stiff or of a soft rope to torsion ( due to its twisting ) - not only to compression / flattening ( due to its squeezing ).
?
Did you mean “shape of knots tied on stiff ropes”.
I could nt mean " knots tied on knots", could I ? ?
There is some B&W “poly-Dac” marine cordage
that sort of fits your need : “sort of” in that the
monofilament PP runs one direction, polyester
multifilament the other (I could be wrong and
it’s nylon, but PS better matches to PP/PE and
hence the colloquial name). (Tends to be somewhat
square-ish, though, per differing material flexibilities.)
Indeed, I’ve often wondered about all the arc’d
up strands going one direction on knots, showing
that they were contributing zilch to holding tension!
(On a fig.8 eye knot, which is known to be strong.)
–dl*
I have been tying a knot every day in 2016. THey are color but have the beauty of b&w.
Very nicely done windychien.
Thank you for sharing and I hope you will share more as they come.
SS
Very nice windychien, I am enjoying looking at your images 
Thank you! I’m so glad you like them. Here is an article from yesterday: https://www.wired.com/2017/01/artist-tied-one-knot-every-day-2016-results-gorgeous/#slide-1
To me, color/non-color choice is partially about contrasting ‘drama’; so partially subjective to what you are used to etc.
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Author shows clean, crisp Black-n-White can do this defining contrasting very well.
But, for me; part of that BW drama would bring me back to an older time,
with ‘grittier’ components of hard work/conditions of rope in this ‘drama’; story told in the picture as part of the scene.
but my familiarity is totally as work device, so looking to feel the gritty work and sweat, rope loaded w/force of the scene i think;
but still think it is the best ‘drama’ from the BW canvas.
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In contrast, i think colorful ‘eye candy’ has it’s merits to the other extreme of clean and smooth.
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Each should draw you in with it’s details and depths i think.
even to the point of perhaps eye fascination opens to light mesmerism of more open mind to learning, as pic looks so right??
i think we have a survivalist animal eye, that rejects false looking pics etc.; doesn’t open to them
as animals we are constantly learning what looks right around us, so can define out of place threats
in drawing this comes up so many times, as just doesn’t look right; you just know something is out of place, but can’t define it.
brain is pushing back, not open when eye says content isn’t right
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i believe things i’ve put together are more labor intensive as a real ‘draw’ back!
but then always trying to leave said construction open to animation..
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edit:Drawing/ animation can also take viewer into theoretical places/views etc. that picture couldn’t.