How lighting can influence on grade appearance

[Garry H (Cut Nut)]

Date: 1/16/2006 11:53:59 PM
Author: michaelgem
Hi Garry,

From your take, it does not sound like I was successful. Successful background - yes thanks. But are you able to draw any conclusions yet?

On a further note to Sergey, it would be most instructive to me and perhaps others, if you could photograph the two lighting circumstances with a wide angle lens, along the line of site, toward the observer''s eyes like my example, to give a picture of the illumination like Garry has tried to approximate.

It would then be easy to understand the performance of the diamond''s in the two lighting environments.

Alternatively, a shot of the whole setup from some side angle would also be helpful.
Great idea - we need photo''s with a dome / upside down metal bowl / shiny sphere of some such thing of the GIA diamonddock as well as sergey''s Eichorst set-up. Side on shots with viewers positions etc etc.
Then we can see the relative intensity - angles etc

Michael Cowing

www.acagemlab.com

 

[Serg]

Date: 1/16/2006 11:40:04 AM
Author: strmrdr
serg,
I find a tilt with over head lighting highly consistant with how people view diamonds in the real world on the finger.
I did a small study and asked 20 people to look at there diamonds and admire them.
Every last one of them tilted there hand back towards them, so the viewing position was over head lighting, diamond tilted, some did it at full arm lenth some at half.
Not one brought it in to there body and looked at it strait down.

Yes. It is usual. What is problem?

 

[Serg]

Re:Steep deep diamonds look best in that environment, and shallow stones look awful.So far the onlky saving grace that I can spot for GIA''s study is that stereo vision somewhat lessens leakage.

Yes. Leakage give contribution, but I think Leakage is not most important reason ( for diamonds Pav 41,5 -40/Cr 35)

Leakage just slightly increasing brightness for Pav 41.5( and Stereo Compensate it for this type diamonds.)
But darkness shallow diamond in GIA light could be very big. It is main problem

 

[michaelgem]

The GIA lighting environment, while not representative of the lighting in my example, is more representative of strmrdr’s common situation where the diamond on the hand is tilted back, moving away from usual overhead illumination toward the line of sight and the viewer’s head.

This creates a lighting profile that is closer to what Garry illustrated, which is reproduced below. As Belle points out, the observer’s head is not obstructing the brightest part of the illumination, which is about 45 degrees from the line of sight.

However, in both strmrdr''s and my example lighting circumstances, there is relative absence of light near the line of sight and the observer’s head. If this is a primary area being reflected to the observer, as it is to a greater degree in diamond cuts with shallow crown angles, those diamond’s will appear less brilliant, both in GIA’s lighting and in strmrdr’s common viewing situation.

In that sense, GIA’s lighting and strmrdr’s viewing circumstances, where there is relative absence of light in the vicinity of the viewer’s head, both reveal the reason for the darker appearance of diamond’s with shallow crown angles when compared to ideal crown angles. (Always need to include the caveat that the pavilion is held close to 41 degrees.) This is true irrespective of whether this absence of light is due to head obstruction.

This is the why of my conclusion that:

>>

Even though Garry and Sergey may think I have gone a little off point, this is all very related to Sergey’s topic header: How lighting can influence on grade appearance. I am addressing the big picture of this topic.

It is my belief that it is typical lighting circumstances that have driven the evolution of the cut considered by most on this forum to be Ideal.

This is also why it is important that optical performance metrics employ lighting that meets the criteria:

“To be meaningful, measurements of diamond beauty should be made in illumination producing optical performance closely approximating the optical performance judged by humans in usual illumination circumstances. “ Michael

I believe, from answers to my inquiries, that GIA has found that judgments of relative light performance (beauty) between pairs of differing diamond cuts using their Diamonddoc lighting correlate well with conclusions obtained from their 70+ thousand human test comparisons.

This whole thread including Sergey’s raytracing, Strmrdr’s and Belle’s observations and Garry’s lighting illustration lead to an understanding of why this might be.

With all this as background, I will next try to respond to Garry’s question:

"Successful background - yes thanks. But are you able to draw any conclusions yet?"

My answer is yes.

Sorry, I always go too long and try to say too much. Please bear with me.

Michael Cowing

www.acagemlab.com

 

[Serg]

re:I believe, from answers to my inquiries, that GIA has found that judgments of relative light performance (beauty) between pairs of differing diamond cuts using their Diamonddoc lighting correlate well with conclusions obtained from their 70+ thousand human test comparisons.

This whole thread including Sergey’s raytracing, Strmrdr’s and Belle’s observations and Garry’s lighting illustration lead to an understanding of why this might be.


Michael, Please clarify

1) How mine or Garry explanations can show what: "GIA has found that judgments of relative light performance (beauty) between pairs of differing diamond cuts using their Diamonddoc lighting correlate well with conclusions obtained from their 70+ thousand human test comparisons". ????
2) Did GIA use different light( Not Diamonddoc lighting ) for obtained from their 70+ thousand human test comparisons? I thought light was similar.

P/S Head and observer distance are very important for grade. But it is old and well known( at least for all us) field. It this topic I try to start discuss something very new( at least for me) . I had shock when I saw such strong phenomena ( good shallow stone went dark)

BTW do you know How GIA received number 70+ thousand human test comparisons, What does it mean exactly?

 

[Garry H (Cut Nut)]

Date: 1/17/2006 12:31:18 PM
Author: michaelgem

The GIA lighting environment, while not representative of the lighting in my example, is more representative of strmrdr’s common situation where the diamond on the hand is tilted back, moving away from usual overhead illumination toward the line of sight and the viewer’s head.

This creates a lighting profile that is closer to what Garry illustrated, which is reproduced below. As Belle points out, the observer’s head is not obstructing the brightest part of the illumination, which is about 45 degrees from the line of sight.

Michael Cowing

www.acagemlab.com

In addition to Sergey''s questions above, I think I can describe the problem that Sergey and I see Michael.

It would not be normal to hold a stone out at 45 degrees and very very close to the head.
The stone would be lower and the head is usually blocking a lot of light - but using the GIA DD the light does not come from around the observers head.

In the GIA study case it seems this is a different environment to oes that we commonly describe and use in models like DiamCalc.

 

[oldminer]

Quite a thread has developed here. It shows the depth of interest in the subject matter. Can any of the expert participants see a resolution of the issues coming from these discussions? It sounds like many people, more or less, agree in principle and in part, yet small issues separate the same folks from making a decision.

Then, too, who among this group of experts is the one, or the anointed group, to decide what will become an international standard? If what is being debated is to mean more than just debating for its own sake, how will the decision making process take place. Who is to be in charge? That would be a large debate in itself.

After you all clear up the angles and the obscurations, how will you judge which diamond looks BEST. Simply a diamond which is more brilliant, may fail to be judged best in overall looks, since how much light is returned, is not the sole factor in the beauty contest. Who will then predict sparkle or scintillation? How much looks best? Can there be so much sparkle that intensity, contrast, is diminished? Who will offer how much is too much?

In essence, are you guys getting somewhere with this? And, where is it you are getting to? Where do you hope to go with this debate and discussion?

If I was a rank consumer reading this, I would be inclined to think the "experts" have no consensus on light behavior, yet the industry spouts platitudes about "Ideal Cut" and "Premium Cut"?

If you create a light prediction model that shows a special cut is highly brilliant, how do you also know for sure it would even look pretty? Too much light return will diminish sparkle. Where are the lines of performance being drawn to show that what is predicted to be beautiful is, in fact, beautiful. More of a particular element of light behavior is not by necessity simply "better".

 

[strmrdr]

Date: 1/17/2006 2:33:09 PM
Author: oldminer



If I was a rank consumer reading this, I would be inclined to think the ''experts'' have no consensus on light behavior

lol
they dont when it comes to how diamond cut interacts with light.
every expert has there pet turf they are protecting that is a small part of the puzzle but no one that iv heard of/from has a good overall picture.
Paul and Brian come closest but they are coming at it as an art not a science and the science hasnt caught up with the art.

That said it is a young science give it 30 years and the youngsters will look back on these discussions and say boy they sure didnt know much back then. What they wont realise is that without what is going on today it would have never got to the point they are at.
So these discussions are usefull in a broader sence :}

 

[oldminer]

"Paul and Brian come closest but they are coming at it as an art not a science and the science hasn''t caught up with the art."

"I''m not an expert on diamonds :}"

When I read your first line I know you just don''t have a handle on what is actually going on, yet you sound so decisive and well informed. Then, I read your sign-off, and you admit to the same.

I have no idea where you live or work, but if you ever wanted to see the real science that has been going on to measure light performance and thereby gauge the beauty of diamonds, you have a standing invitation to come see the AGA lab and I will get you the chef''s tour of the ImaGem R&D office. No, we won''t tell you the trade secrets, but maybe you''d speak with Dr. Aggarwal and he''d share some of his past 9 years of study in this research with you to give you more inside knowledge and a better trust in the science side of these expert systems that are now working, and not just in theory.

Several of the particpants does have a stake in the outcome of these discussions, including myself. I am not strictly unbiased, but I am also known as being open minded and a good listener. If any of the experts here, including Strmrdr, wants an opportunity to discover more, please let me know about your interest.

This is a personal invitation on my part. Dinner and drinks included. Please don''t feel I am in the attack mode. I want to see this process go forward.

 

[strmrdr]

Dave thank you for making my point for me :}

I make a personal opinion remark from the outside looking in.
I dont have a stake in this other than being an interested outsider and to learn kewl stuff.

Yet you have to attack me and stake out your imagem turf yet again.

As far as the statement you quoted goes...
Brian has been cutting/designing diamonds since atleast 1995 and likely earlier that score at or near the top on the tests science is just now coming up with to test them against.
He isnt the only one but is one we all know.
Am I wrong in saying that his art is ahead of diamond science?

edited: changed "top out" to "score at or near the top on" to better reflect reality :}

 

[oldminer]

You are a bull headed guy. It was a friendly invitation to inform yourself if you wanted to do so sometime at your convenience. An attack, be serious. That is not what I'm all about. People who want to know more don't get so defensive when nothing is coming at them......Its your loss, but what the heck, I tried.

Sorry to all who wrongly think I was attacking anyone. It was a friendly gesture and I do have an open mind. Did anyone else see the response as an attack? You can PM me rather than ruin the good thoughts of the thread.


I'll read what follows but promise no further comments. No point in going where I'm unwelcome.

 

[solange]

If I was a rank consumer reading this, I would be inclined to think the "experts" have no consensus on light behavior, yet the industry spouts platitudes about "Ideal Cut" and "Premium Cut"?
Old Miner

I must admit that, as a rank amateur, I am confused and beginning to wonder if there is any consensus among the experts as to just where the cut-off is as to how to judge a desirable stone. I do not think I can tell brilliance, fire, scintillation, ect. and there does not seem to be a general agreement. To me, either a stone has life or it doesn't and I do not know where the life is coming from. Also, after reading the post on color appearance and learning that a diamond that is the best coor and cut can look bad in direct sunlight or other lighting situations, the color grading process is also confusing since diamonds go where the wearer goes and one has no control over the lighting or environment.

However, although this thread is way above my head, I still feel it is useful and I would be sorry to see Old Miner stop participating in it since he is one of the most informative contributors on Pricescope and I highly value his participation. He is always very generous with his time and information. I am sure these discussions among experts will lead to greater understanding in the industry as to how to grade stones and the result will be more information for the consumer as these are very frank and open discussions. The differences are opinions from experts. Thesis, antithesis=synthesis--or a melding of expert input into a subject in which there are various views will lead to a better understanding and resolution.

I hope he will reconsider and rejoin the discussion where he has been so informative and scholarly.

 

[Hest88]

Date: 1/17/2006 5:52:02 PM
Author: oldminer

I''ll read what follows but promise no further comments. No point in going where I''m unwelcome.

Oh for chrissakes, Dave, please don''t let Strmdr drive you away; you know he has no qualms about being difficult. After all these years the optics discussions are still way too complicated for me to participate in but I still find them fascinating. I hope *all* the people who are at the forefront of cut research---including you---will continue the debate no matter what those in the peanut gallery might say.

 

[Garry H (Cut Nut)]

Date: 1/17/2006 2:33:09 PM
Author: oldminer
Quite a thread has developed here. It shows the depth of interest in the subject matter. Can any of the expert participants see a resolution of the issues coming from these discussions?

Dave don''t go all limp on us.
Question - how would you go about this issue?
I could say GIA''s study was a waste of money and their grades are useless - never buy a GIA graded stone and ignore their cut grade info - but that would be a waste of virtual ink.

I prefer to review their processes, as is Sergey, and raise questions where I think they may have made errors in method etc. I do not think it does anyone any good to have a public war. However i hope and believe that enough people with enough influence will read these discussions and ask enough questions (from outside and inside GIA) to lead to a review of methods and results.

You too could / should / must participate. But I would prefer you participate in the review process, rather than to say that the whole method should be replaced by direct assessment.

Ultimately we will collate this information and perhaps write a Journal article for PS as well as for peer magazines etc.

 

[michaelgem]

Some see my message is a defense of GIA, but it is more an analysis of why they have come to the conclusions they have. These findings and conclusions arrived at after 15 years are reflected in their Facetware.

My judgments in the area of diamond cut design and optical performance differ from both those of GIA and AGS as do the judgments of Sergey, Garry, John, David and others posting here. But there is much more commonality than differences between judgments of GIA, AGS, those on this forum, and myself.

I am exploring that commonality, where I believe fundamental truths in all our research and observations reside. That is why you observe me pointing out such commonality when I see it. By drawing parallels between observations and findings by those on this forum and my observations and conclusions contained in my writing from 2000 through 2005, I am pointing to our commonality, wherein I see the truth.

I hope this helps others see it too. Most of us devoting our time and effort posting on this forum have similar aspirations.

Michael Cowing

www.acagemlab.com

 

[Garry H (Cut Nut)]

Date: 1/17/2006 11:33:55 PM
Author: michaelgem

Some see my message is a defense of GIA, but it is more an analysis of why they have come to the conclusions they have. These findings and conclusions arrived at after 15 years are reflected in their Facetware. In the Foundation article they

My judgments in the area of diamond cut design and optical performance differ from both those of GIA and AGS as do the judgments of Sergey, Garry, John, David and others posting here. But there is much more commonality than differences between judgments of GIA, AGS, those on this forum, and myself.

I am exploring that commonality, where I believe fundamental truths in all our research and observations reside. That is why you observe me pointing out such commonality when I see it. By drawing parallels between observations and findings by those on this forum and my observations and conclusions contained in my writing from 2000 through 2005, I am pointing to our commonality, wherein I see the truth.

I hope this helps others see it too. Most of us devoting our time and effort posting on this forum have similar aspirations.

Michael Cowing

www.acagemlab.com

I hear you Michael. Thanks for the reply.
You are looking for areas of agreement. I guess i am concerned about areas of difference like that displayed in this image.

GIA might give this stone a grade of excellent, where as AGS might give it AGS4 according to their various proportion based guides.

I am concerned that such differences will result in confusion for the diamond buying public and those professional in the industry who are not as aware about diamonds as they could be (many retailers for example may have trained as watchmakers, or still operate on the old Ex/Ex 60:60 thinking).

For a diamond cutter who has a piece of roungh on the scanner and see''s he can make a GIA 1.000ct Excellent, or an AGS 0 ''ideal'' of only 0.98ct - it is a no brainer - the 1.00ct GIA will fetch a higher price and in the interest of the company owners / shareholders......

Michael, which stone would you recomend one of your family, friends or clients to buy?
The steep deep 1.00ct with these GIA proportions with the proportions listed on this slide?
Or would you suggest an alternative - look and find perhaps an AGS 0 stone which might cost 5% more?

 

[Serg]

Date: 1/17/2006 5:52:02 PM
Author: oldminer
You are a bull headed guy. It was a friendly invitation to inform yourself if you wanted to do so sometime at your convenience. An attack, be serious. That is not what I''m all about. People who want to know more don''t get so defensive when nothing is coming at them......Its your loss, but what the heck, I tried.

Sorry to all who wrongly think I was attacking anyone. It was a friendly gesture and I do have an open mind. Did anyone else see the response as an attack? You can PM me rather than ruin the good thoughts of the thread.


I''ll read what follows but promise no further comments. No point in going where I''m unwelcome.

re: Did anyone else see the response as an attack?

I have no idea where you live or work, but if you ever wanted to see the real science that has been going on to measure light performance and thereby gauge the beauty of diamonds, you have a standing invitation to come see the AGA lab and I will get you the chef''s tour of the ImaGem R&D office

Who will then predict sparkle or scintillation? How much looks best? Can there be so much sparkle that intensity, contrast, is diminished? Who will offer how much is too much?In essence, are you guys getting somewhere with this? And, where is it you are getting to? Where do you hope to go with this debate and discussion?


Dave, I saw same.

( All who remember old my and Storm disputes with our about Imagem can see attack here. Please understand this fact.)

re: And, where is it you are getting to? Where do you hope to go with this debate and discussion?

Firstly - Understanding ( What is important , what is not important for grade, How it is work ...) Before you will do any good standard, you need receive deep and good Understanding .
Only from you depends What you can receive from our posts and discussion with us. You are welcome for discussion and understanding( nobody welcome for slogan( without any real facts) promotion.

I received a lot of understanding from such discussion on GK, DT, PS. I am very happy meet any new strong and smart opponent. Good "scientific opponent" is necessary for process of deep and right UNDERSTANDING.

A lot of people was disagree with my statements in this topic. I received several private letters and calls. They was active my opponents. Thanks a lot to all.
Some people was passive opponents( My first statements was not clear enough)

I changed my "language" and immediately receive new UNDERSTANDING for some people and ME. I want be honest : Education is not my task. I am working on PS for MY UNDERSTANDING firstly( Not for your, or Garry, strmrdr , .. UNDERSTANDING . I am very happy if I can help to other people to receive my UNDERSTANDING, but it is not my main task on PS)

Secondly ,
I want create Cut Study science wide community. One company can not create good enough Cut grading system, Light standard,... We need share our knowledge, have open discussion, we need science( have other part which is important science community. Science can not exist without open science community. Current situation in diamond industry is abnormal( "feudal time ")

. Is it more clear for you now what I am doing ?

You can help us and increase your UNDERSTANDING or continue your way. It is your choice only.

 

[strmrdr]

getting back on topic..and leaving gia out of it...Iv rounded up your main points and I think left your meaning intact.

"Just imagine: You turn on light in standard light equipment and brightest diamond become to darkest diamond."

"1) First is similar to 'Office type' with white walls and big windows with white textile jalousie (jalousie = venetian or slat blinds). Stones is inside Magna color scope ( Eickhorst company) . BTW This phenomena strongly depends on distance between stones, background and light. Light in Magna color scope turn off



2) Second . Same + light turn on."

..........
end of quotes
..........

simplified:
diamond is in a box you turn the light on above the diamond and the diamond appears darker.

Iv been playing around with DC custom light envirements and havent duplicated it.

 

[Garry H (Cut Nut)]

Thanks for doing that Storm.

Everyone can start again from this point.
Dave please ask Prof Agwarral to get involved too.

This Gem File below is not very good Storm, but best I can do.

Click on the file and save it (if you have DiamCalc - or just open the GemAdviser for those who do not) but change thefile name to .dmc from .gem and then you can open it with DiamCalc.
Then you can save the lighting format.
Ask if you do not know how

 

[strmrdr]

Date: 1/18/2006 4:53:17 AM
Author: Garry H (Cut Nut)
Thanks for doing that Storm.


Everyone can start again from this point.

Dave please ask Prof Agwarral to get involved too.


This Gem File below is not very good Storm, but best I can do.


Click on the file and save it (if you have DiamCalc - or just open the GemAdviser for those who do not) but change thefile name to .dmc from .gem and then you can open it with DiamCalc.

Then you can save the lighting format.

Ask if you do not know how

yep that worked.... for others:
change extension to dmc
open in DC
go to options
lighting
customise
click save and save it.

Then you can use the lighting model using the load button in the custimise window to load it then click apply.
.................

Your demo has the dark part but the default state with them off isnt the light return like the pictures which I was trying to do.

The light return from the first picture source couldnt be eliminated by the other lights was the problem I was having.
The diamond kept returning that light even with the others at high angles.
Im rather confused as to where the light that was lighting them up in the first picture went.
Or am I missing the step where it was taken away?

 

[strmrdr]

I knew this looked familar.
see how the high angles gives a darkfield affect and you can see the inclusion and the pavilion facets thru the table.
someplace I read about using a fiber optic light shining like that if you didnt have a darkfield attachment for your microscope but I cant find it.

 

[Garry H (Cut Nut)]

This is not real good Storm - but if you play with it you might get better.

It is a general flood light from the front

Date: 1/18/2006 5:14:58 AM
Author: strmrdr

Your demo has the dark part but the default state with them off isnt the light return like the pictures which I was trying to do.

The light return from the first picture source couldnt be eliminated by the other lights was the problem I was having.
The diamond kept returning that light even with the others at high angles.
Im rather confused as to where the light that was lighting them up in the first picture went.
Or am I missing the step where it was taken away?

Sergey''s point here in the first photo is that there is hardly any light - our pupils would be wider open (as would the camer aperature) and you can even see that the lower photo has greater depth of field - and there is more bright light from abaove - where as the top photo - the lower part of the piece of perspex is lit up - because the light is coming from the ambient light in the room.

In the lower photo our eyes have adjusted to a very very intense light that is very close to the stones.
The light has only created a few small sparkles in the rounds - the body of the stones is quite dark - but if we took the same photo with the same setting as the first shot - they would be completely over exposed.

The princess cuts are doing almost the exact opposite.

Dave this is very important for Imagem - it is possbile to have a lighting set up that you think is good for one stone shape - but is shocking for another. A little birdy told me that he no longer believes in the Brilliancescope because of this very type of situation - a cetain type of bad stone can actually get a blow away fantastic result.

Please people - corrrect me if I am wrong - Sergey is not helping us here - he is playing Socraties

 

[Serg]

Re:The light return from the first picture source couldnt be eliminated by the other lights was the problem I was having.
The diamond kept returning that light even with the others at high angles.
Im rather confused as to where the light that was lighting them up in the first picture went.
Or am I missing the step where it was taken away?

We can not model full eye dynamic range in DC yet. we can use less then 256 gradation gray only, it is not enough for model eye brightness adaptation on monitor( We need add HDR to DC firstly)

re:Im rather confused as to where the light that was lighting them up in the first picture went.

eye brightness adaptation to new level of Brightness is reason of loss the office light .

 

[strmrdr]

question it looks like the princess cuts table is at a different angle than the table of the rounds.
expecialy the left big princess looks like its leaning back more.
using your diamcalc lighting when the princess cut is tilted back it lights up more than when its at the same angle as the rounds.

 

[strmrdr]

Date: 1/18/2006 6:18:46 AM
Author: Serg
Re:The light return from the first picture source couldnt be eliminated by the other lights was the problem I was having.

The diamond kept returning that light even with the others at high angles.

Im rather confused as to where the light that was lighting them up in the first picture went.

Or am I missing the step where it was taken away?

We can not model full eye dynamic range in DC yet. we can use less then 256 gradation gray only, it is not enough for model eye brightness adaptation on monitor( We need add HDR to DC firstly)

re:Im rather confused as to where the light that was lighting them up in the first picture went.


eye brightness adaptation to new level of Brightness is reason of loss the office light .

kewl thanks that was driving me batty trying to figure that out :}
Now if I could just find that webpage im looking for.

 

[Garry H (Cut Nut)]

Yes Storm - they are all resting on their pavilions and they are all different nagles

 

[Serg]

Date: 1/18/2006 6:25:26 AM
Author: strmrdr
question it looks like the princess cuts table is at a different angle than the table of the rounds.
expecialy the left big princess looks like its leaning back more.
using your diamcalc lighting when the princess cut is tilted back it lights up more than when its at the same angle as the rounds.

Angles are more or less same. ( +-5 degree, I think)
It is not very important: We checked this phenomena in big range angles, tilt, moving,..

 

[Yuri]

This is a picture of Magna Colorscope, Eickhorst System production, an observer, and the set of stones under discusion. One upper light is turned on.

 

[diamondsrock]

from michael: >>

ok, so now as a regular consumer I am completely confused. The most beautiful diamond I have seen (at least in pictures) on Pricescope had crown 34.1 and pav. 41.0. Is this considered a shallow stone and are you saying it will have less brilliance? These are the angles I was shooting for in my next stone but now I''m confused!

I haven''t seen one yet with these angles anyways in all my searches through vendor inventories here but I was thinking if one came up I would be interested. NOw I don''t know.

 

[Serg]

re: k, so now as a regular consumer I am completely confused. The most beautiful diamond I have seen (at least in pictures) on Pricescope had crown 34.1 and pav. 41.0. Is this considered a shallow stone and are you saying it will have less brilliance? These are the angles I was shooting for in my next stone but now I'm confused! I haven't seen one yet with these angles anyways in all my searches through vendor inventories here but I was thinking if one came up I would be interested. NOw I don't know.


P41Cr34.1 is great combination .

Do not worry , be happy.
Please do not use anything from this topic and any other my topics for your solution about purchasing.