How to show Shiny & Sharp?

One of my interests is making things polished and sharp,
down to sub-micron levels. It is not difficult to show a good polished
surface; just watch out for blown highlights.

This is a watch caseback opener. It is not supposed to have a sharp
edge. The bevel has a mirror-polish, but the large flat area above it
is mottled, thus it cannot take a good shine.

So far, the task was relatively easy.
But how on earth does one visualize sharpness?
It is easy to show a strand of hair, split length-wise.
But that does not document the edge itself…

Have fun!
Claes in Lund, Sweden


The effect of sharpness.

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One of my hobbies is woodworking with hand tools. Sharp tools like chisels, saws and plane irons are essential to achieve good results.
With a well set up plane for a fine cut and a really sharp plane iron it is possible to take off such thin shavings that you can read eg. the dial of a watch through that shaving - that shows sharpness indirectly.


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For shiny, I think sometimes strong highlights (like blown) can show it. Sort of Specular highlight - Wikipedia So i guess local contrast can help too?

Could you create an HEIF with either an HLG or PQ still image?

Joking aside, I started on the wrong foot: I believe this is a capturing challenge, not a thread solely for remarks and quips. :wink:

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Testing my kitchen knife (because :fr:) and my color light source:


Sharp for sure :sunglasses:.

[Edit: wb]


Or not so sharp… or shiny? Anyone guess what this is? Hint: it is meant for cutting - otherwise I wouldn’t have posted in this thread.
I can’t remember what lens I used… it was reverse mounted on a set of Pentax bellows… I think it was a 28mm K-mount Tokina. @Claes , hope you don’t mind me posting in here…

Impromptu guesses: Bottle opener? Pipe cutter?

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It’s part of a chainsaw - the cutting teeth, I guess they could be called.


Claes , hope you don’t mind me posting in here…

Not at all!
However I wonder whether someone will be able to
find the proper reply to the original question:

But how on earth does one visualize sharpness?

How to document in an image that an edge is sharp,
as opposed to blunt…

I think the best way would be to show it in action, cutting through something… not quite sure how though. I’ll try to try!

@afre and @MetalMick99 thanks for the guesses, Michael you’re absolutely right. :+1: A chainsaw cutting tooth. The field of view is about 10mm for a guess. Thanks!

Does poking through something count?

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HELP! :running_man:

No. That is not considered a cut,
and does not need a sharp edge.

A hint: there is a way to show a sharp edge…

Oho! I think you know already :slightly_smiling_face:… not that it helps. I’ve no new ideas!

I knew I should have put a sarcasm tag on my post.

I should also have used sabre rather than épée, since this is a cutting weapon. The difficulty is that at top level competitions, the background is black, which makes the blade difficult to see. At lower levels, you often lose the blade in a messy background.

Is it not possible to use a speedlight at a low setting? Could create some really cool reflections with the dark background and the athletes in the foreground :thinking:

At a competition, no. I have used flash and other light sources in a club situation.

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