Thread: Same edge, same spot, same magnification, different light...

Originally Posted by gssixgun

Am I seeing a Double Bevel????

Yes, it's an edge with a secondary bevel. I've been experimenting with it quite a bit lately. I think it's great for comparing the capabilities of various hones, because the very edge is only formed by the last hone in the progression. (There's lot to be said about this topic, but a bit besides the scope of this thread)

Originally Posted by Utopian

I used to do a lot of microscopy work (and have a lot more to do soon) and it's amazing what a little change in the parameters can to to your interpretation of what you see way down there. Those are great photos to show the difference the light angle can make!

That was my point exactly. The angle of the light hitting the subject makes tremendous difference, even within very few degrees of variation. All pictures are lit by the same light source, only with slightly different angles. The razor itself was not touched. Magnification is 50X, by the way.

For those who wonder, the scratches running in opposite directions on the second picture, are actually very shallow strop marks.

Bart.

Same edge, same spot, same magnification, different light...
Bart

All pictures are lit by the same light source, only with slightly different angles



Go figure it out now?

What was the purpose of your message?

If I may be so forward, I believe it was to show how different your pictures for edge analysis can be when the light is hitting th subject at different angles. This is a fundamental of photography.

First sentences how he started his threat and second one how he did explain ?
at first "different light "
next "same light"
what he was trying to do ????
confuse us or to get help from us?

He just wants to illustrate that pictures have their own peculiar way of telling a truth.

Originally Posted by hi_bud_gl

First sentences how he started his threat and second one how he did explain ?
at first "different light "
next "same light"
what he was trying to do ????
confuse us or to get help from us?

I'm sorry Hi_bud, never meant to confuse you.
I've should have titled it "different light conditions".
Indeed I was trying to make a point that pictures at magnification can be very ambiguous.
The same edge may look completely smooth or deeply scratched. All it takes is a minor adjustment of the lightng angle.
Actually I saw a thread last night were someone posted scratch patterns left by two different hones. I noticed how he placed the razors at a different angle under his scope (which has the same effect as altering the lighting angle). I wanted to illustrate how easy it is to jump wrong conclusions out of that, but decided to start a new thread, rather than offense someone that I respect, and know to have only good intentions with sharing those pictures.

My apologies for the confusion,
Bart.

for clarification.I was just a little confused and trust me i don't have any hard feeling.thank you for a nice pictures it help .if you could compare 50x, 100x to 200x same blade in exact condition i would appreciate.on y microscope i can see only 50 aND 100x,300 doesn;t help much.
thank you

Originally Posted by Bart

Yes, it's an edge with a secondary bevel. I've been experimenting with it quite a bit lately. I think it's great for comparing the capabilities of various hones, because the very edge is only formed by the last hone in the progression. (There's lot to be said about this topic, but a bit besides the scope of this thread)

That was my point exactly. The angle of the light hitting the subject makes tremendous difference, even within very few degrees of variation. All pictures are lit by the same light source, only with slightly different angles. The razor itself was not touched. Magnification is 50X, by the way.

For those who wonder, the scratches running in opposite directions on the second picture, are actually very shallow strop marks.

Bart.

Very dramatic difference between the first picture and the last.

I'm sorry if this question falls into the "outside of the scope of this thread" realm, but without getting too deep into it.. Just wondering if you're creating the secondary bevel angle by putting two layers of tape on the spine? That's all I'll ask.. promise.

Hi All

Realise its a while since my last post, but I thought I can add something useful to this.

I use a small handheld microscpoe with a built in light source to see how things are going during honing - the every popuar tandy style of thing. It is exactly for the reasons above that I set the focus on maximum and hold the edge of the razor below the base of the 'scope. This way I can angle the blade and get the light reflecting off the edge in several different directions, thus seeing the "whole picture".

It requres a steady hand, but I find it really helps to get an overall impression of the bevel edge along its entire length.

Sunsi

Bart, I never realized how dramatic the differences could be under differing angles of lighting, or differing blade angles for that matter. This will make me view what I see under the microscope in a whole different light.