Colour of the steel

[markturner]

Hi, in some of my literature, particularly the handbook from the To-ken society i just joined, it refers to looking at the colour of the steel as part of assessing the quality of the blade.

 

Try as i might, i cannot seem to differentiate any shades of yellow, blue, white or black as referred to in the text on any of my three blades. is there a "trick" to doing this, or is it just my untrained eye? All my blades look like shiny silver to me......

 

Thanks, Mark

[paulb]

Hi Mark,

If there is a trick to doing it I still havent found it and I have been trying since 1983! In addition I have been involved with colour measurement for about the same period and that hasnt helped. I find assessing colour in steel very difficult. The only time I can do it is when comparing blades side by side. I am currently doing some work on an old Awataguchi piece. I had it sitting next to a Yamato Shikkake blade and the Awataguchi was deifinitely dark blue in comparison.

I have also had a blade which was defined as having typical Northrn Province dark steel. After 2 or 3 years I was still trying to see it.

[Bugyotsuji]

Just had this conversation with a couple of other members of our local sword appreciation society. Is it really true, or an article of faith? They laughed and agreed. They said it is very difficult to see 'color/colour' in a lone blade, but side by side as Paul says above, the job becomes easier.

 

I was staring at an Aoe blade after the sensei mentioned its typical black quality, and well, just perhaps it had a bluish tinge to it, I was thinking. :lol:

[Eric H]

This has always been a mystery to me... ... how and in which light can the color shades be seen at best? Daylight, artificial light, or to look at a specific angle?

 

Eric

[Brian]

And then nugui can change the color of the steel when applied by someone who knows what they are doing....

 

Brian

[cabowen]

And then nugui can change the color of the steel when applied by someone who knows what they are doing....

 

Brian

 

Or, more often in the West, doesn't know what they are doing....

 

Discerning the color of the steel is maybe the most difficult part of assessing a blade. It does help to have a comparison. It also helps to have good lighting and a proper polish. Seeing many blades in hand is essential. You can't get this from a book.....

[b.hennick]

I always thought that color was best seen in the kissaki as it is easily changed in the rest of the blade.

[David Flynn]

I've always found natural light, holding the blade down at about 45 degrees.

[markturner]

Thanks for the answers guys, so I am glad I was not missing something there...

 

Cheers, Mark

[Darcy]

This is a really good question from a bunch of different viewpoints.

 

A polisher has a lot of leeway in altering the apparent color of a sword. Some schools are supposed to look a certain way and the polisher can help that along by doing his job to enhance those qualities. Or maybe disguise other qualities.

 

The rest of it is very interesting because there are a lot of issues involving our brain lying to us about what white is, and then our inability to recognize absolute color when we see it, along with a strong ability to recognize differences in color (relative color).

 

White problem... in something like a blue deficient light source (light that is greenish-red, like a tungsten light), this has a yellow cast that is universal throughout a scene. We can both use reference objects (a piece of paper) and the light source itself to kind of on the fly adjust for the lack of a particular part of the spectrum in our judgements. We have automatic white balancing. Not perfect but someone will still say that paper is white under their tungsten reading lamp. Blast them with a daylight spectrum bulb and they'll say it's blue for a few seconds before their brain recalculates and it will start looking white again.

 

The problem then is that without a good reference and without a balanced light, we are really fudging it in our brains about the colors we perceive.

 

You cannot get a good handle on blue in yellow light. Yellow light can be considered the absence of blue or very strong green and red light together. Without a lot of blue participation it becomes difficult to make judgments about objects that reflect blue.

 

In perfectly yellow light, blue objects will in fact appear to be black.

 

This doesn't hold for all colors... a purple object will appear to be purple in low-green light (hard to find an example), will appear to be blue in low-red light (almost fluorescent) and appear to be red in low-blue light (tungsten light), while in balanced (white) light it appears purple. Under those three scenarios, blue will look: blue, blue, black, and blue.

 

You can't make blue look red or green. Blue is either blue or black.

 

So us with our swords and yellow lights lights and brains constantly re-deciding what white is, and an inability to precisely measure what absolute color is anyway... we have a very hard problem trying to decide if a particular sword is going to be bluish or not.

 

Until you put it beside another sword.

 

Then as long as you have a tiny bit of blue in your light, then you can tell which one is reflecting *more* blue at you. And that one becomes the blue steel.

 

So you really need a reference if you are going to judge color. Then even in bad conditions, if you are just deciding which is more of something than the other, you are OK. Diamond graders use this approach.

 

They calibrate with machines that test the spectrum, give reference colors out to the graders, and the graders can compare D to E to F to G and when they find a place where the stone they want to grade fits nicely between two places, they can give it the same grade.

 

Your own best chances are to use daylight bulbs. Natural light is good but it rapidly changes color depending on clouds in the sky. Daylight bulb is stable in color. Use this always for your study. Study in the same place.

 

It may be possible that someone who studies really hard and uses a fixed environment over a long period of time can train themselves to have "absolute" color for the thing they're looking at. It won't be perfect but I would not be surprised if someone with decades of experience can look at a sword given in their study and tell you about its color. But it would take a lot of careful training and the more someone practices at it the better they will be.

 

This all of course is in the subtle range. That is, the generally non-obvious stuff. Paint a sword blue and we all will know it. We know when a photograph is way out of color balance but there's a range where we'll always accept it as being legit... even when by the mathematics it's pretty far out.

 

If we didn't... we'd probably go insane because when the sun moves in and out of the clouds, the relative change in color of a white object is very dramatically different. Just walking into the shade of a tree your teeth are pretty blue. Then sit down in the grass and they're green. Keep talking and as the sun sets they will become yellow and then orange.

 

But we never look at someone's teeth and think this, they're white... or possibly yellow.. or brown. OK, model's teeth are white. But that's the overall problem again, within a select range our brains will adjust and tell you it's white. Push very far out of that range and those teeth will be yellow and push very far again and then brown.

[Tcat]

Great post Darcy, many thanks!

 

Not sure where I got the idea, but could it be said that in terms of very rough generalization, koto blades tend to be more blueish (or darker) in colour than their more contemporary counterparts?

[Guido]

And here I am, thinking the color changes I experienced were an after-effect of the stuff I inhaled in the seventies ...

[sanjuro]

For what it is worth, I have always found that true to what has already been said, differences in the colour of steels is most pronounced when done in comparison with another blade. However, one might more easily discern it in daylight rather than in an artificial light. The darker colours of koto steel are best seen in daylight as they were first noticed hundreds of years ago. Whereas the activity in a blade is invariably more evident in an artificial light. Most daylight (and it varies from country to country) is relatively blue compared to the yellower nature or whiter nature of artificial light. Koto steel is generally more grey than Shinto steel.