Rembrandt xray study- some select metals looks like negative or positive images

[Mustafa Umut Sarac]

I was reading a paper on rembrandt paintings and I found a xray study for different paint pigments metal elements and I found something very interesting.
Some metals looks like negative , some metals looks like positive.

What is the meaning of that ?

Please find single page PDF attached.

Umut

 

[VPooler]

*sigh*

This is the wrong forum for questions like this. There are physics forums around, go ask them about X-Ray imaging and such. This is not an alternative process, this is not even photography related.

 

[Mustafa Umut Sarac]

Estonia...

 

[MDR]

Mustafa do they actually write that some metallic pigments look like pos and some like neg if not I would say the images look like pos and negatives because that's what they are. Different contrast and pos negative view to enhance the image. Lead based pigments also usually block X-rays better than none lead based pigments. Josef Maria Eder and Valenta made an X-Ray showing the results of X-raying different materials http://www.artic.edu/aic/collections/citi/images/standard/WebLarge/WebImg_000243/165305_2850322.jpg
nr. 4 is lead and nr. 1 silver

Vpooler the question is a photographic one as X-ray film (in this case evil x-ray) is used by LF Photographers and X-Ray is also a photographic process. Furthermore the look of certain materials under certain lighting conditions is relevant to photography.

 

[Mustafa Umut Sarac]

MDR, No they dont say that but I dont think they would make a positive converted to negative also. I found it interesting because you can print a photograph with negative xray scan. Additionally your image reveal positive and negative images also.

I found it very interesting that if painter tries to paint a negative and positive with different colors for different tones. Its very very exciting.
Today I will try to convert it to positive and than play with the curves.

BUT I am not sure about anything also. I will write to wetcanvas and see the result , plus a physics forum as said.

 

[MDR]

The images are the results of X-ray fluorescence meaning it's the fluorescence of the metal that is being recorded. "Under the energetic X-ray light, different pigments fluoresce in a specific way......With the use of X-ray radiation, the scientists excited elements to fluoresce, including calcium, iron, mercury and lead." The images were also enhanced to show the differences in fluorescence of the pigments as well as show the different paints and where they were used.

In short the less the pigments light up under X-ray the darker they are in the final image. They are not pos or neg they just reflect different amounts of light. Think dark cloth vs light cloth one reflects a lot under visible light the other not as much but you wouldn't call them pos or neg.

Still interesting work thanks for the link.

 

[Mustafa Umut Sarac]

mdr,

Here is the full paper , thank you for shed light to it.

umut

 

[MDR]

Thank you

 

[Perry]

FWIW:

My father was, for a time in the 50's, an Xray tech x-raying steel welds on surge tanks at the Ft. Randall Dam in Pickstown, SD. Being naturally curious and inventive, he took some x-ray 'pics' of his Zippo lighter and his Hamilton wrist watch. The Zippo was particularly interesting in the way the flint striker spring was detailed. And the watch pics showed various levels of the gears and springs. Magnification was 1:1 so the detail was superb. These were all hard copy x-rays, not digital lke today.

Perry

 

[Mustafa Umut Sarac]

Perry,

I have ASME certificate on nondestructive testing with Ultrasound. It costed me 550 dollars and no use since 1999. I was thinking to test my aluminum dory welds , such a idiot I am. I went to welding class also. There was xray course also. I have 500 pages of course notes. But all good things does not go to garbage, I have nearly 10 patent applications. I forgot what were they about. I heard all steel welders died young , if I am not wrong due to cadmium , oh no lead. They turned in to zombies , especially the ones weld pressure vessels of nuclear pressure tanks. Such heros or victims.I watched a movie about first nuclear test , before test , they question the soldiers and elect from does not know nuclear harm. Than they used them as a experiment. Last place you want to be a soldier , nuclear countries.

Umut

 

[TimFox]

X-ray fluorescence is an example of "dark-field" imaging, where the image itself is dark in the absence of the fluorescent element. This is how Superman's x-ray vision works "in reflection" (presumably by backscatter), as opposed to normal x-ray imaging "in transmission" which is bright-field, since a hole in the object is rendered bright in the transmission image. (Of course, if recorded on x-ray film, a bright spot on the image becomes black on the negative.)

 

[RalphLambrecht]

mustafa,if you find this very,very exciting,then. I suggest ,you need to get out morebut I agree I's interesting.

 

[Mustafa Umut Sarac]

Hello Ralph ,

I am living in far west edge of one the crowdest cities in the world. I found east end is very beatiful but no energy and money to cope with that crowd. Whatever speed metro achieves , its a very very long road , need to cross from Europe to Asia. I am waiting Leica Mini Elmar 35mm from Germany and I will go there with two Leicas at may with your excellent advise. As you felt , I stucked in to that room.
I can go to Prince islands and spend a night in tent also. Thank you for enlightment.

Umut