Why is Silver Used in Radiographic Film?

Silver halides are about the only photochemical that can render the negative image in sufficient detail. The thickness of the coating ensures that the film is so sensitive that the minimum exposure of the body to the X-ray source is needed. Therein lies the cost.

"are about the only photochemical"

What are the others then? Are there any others?

What about gold halides, Aluminium Halides, Copper Halides...?

I do industrial radiography on a daily basis and would like to know if there is not an cheaper alternative to the high cost of films.

Sure there are others. It depends upon whether a lethal dose of X-rays can be given to the poor recipient!

• "Dear Mum. Imagine that. Entered hospital with a broken ankle. Came out with it strapped up nicely though dying with radiation poisoning. Love, Quobaldt."

I do industrial radiography and I have never ever had one plate or pipe complain about the amount of radiation I gave them...

Then the next thing to do is to get onto the film manufacturer's technical helpline and ask why it is done that way.

Medical radiography came first. Plant radiography jumped on the bus when it came past.

Almost all Non Destructive Testing techniques have their origin somewhere else, mostly from the medical field (UT and RT).

Film manufacturer's do not have answers. Maybe they are too involved in trying to sell the film and not too involved in trying to find the cheaper alternatives. Digital imaging is trying to help but is also still a bit expensive.

I thought I will ask "you", maybe there is an answer nobody thought about yet...

There is also the particle size of the silver halides which can be made quite small and still remain photoreactive with high sensitivity. Kodak had chemists all over this problem for decades and silver was the best material they could come up with from a cost / performance perspective.

What about gold halides,

Is gold cheaper than silver in Africa? If so I would catch next flight to Africa!

The silver cost is negligible in the over all film cost. Fabrication, distribution, and profit margins are where the money is.

Same goes for dental amalgam. It is not what is in it but how it is made and distributed.

It is that price because the market pays that price.

I believe Lead Iodine film may be available but it is not very sensitive.

Where can I get more information on this? Is it currently used anywhere?

My friend where I heard about it is not available but I did a quick search on Google for "Lead Iodine film" and found some info.

quobaldt; silver is used in most photographic film, it is/was big business recovering the silver from the negatives. now days they skip that and load the x-ray image into the computer perry

I spent 2/3 of my military career some years processing/printing/handling film for Uncle Sam, back in the cold war, when there was no digital and the film was from aircraft and orbital platforms. You cannot only look at the cost of the film alone. You must also consider the cost and nature of the chemistry to process (develop and fix) the image along with the degree of level of image quality that must be met.

Silver Halides are sensitive (to visual light as in photography, and to x-ray,) such that quality consistent film bases can be made and the resultant image processed with confidence. If you change your film type, you will need to change your chemistry, also impacted is the latitude that the film allows you to error in your chemistry mixing, it's age since you put it in service, as well as in latitudes in film processing timing and the temperatures of your chemicals - to name just a few of the side affects.

If you look at the HC 110 processing for black and white imagry, it is a staple for silver halide image production because you can process multiple images over a range of fresh to slightly fresh to not so fresh developer with a variation in time and temp. and still obtain an acceptable end product image. There is the reason for Silver being the standard against which other film products were measured - and silver repeatedly won across the industry. It's in the BIG PICTURE, (sic) rather than in the single component of the overall process.

If there was anything better, it would have been in use immediately....especially if it was also cheaper.....industry is not stupid!!!

wanna bet...?

why you ask question if you no the answer?

Thank you for the link.

I know Industrial Radiography is going in the digital direction, we are. I just wondered why silver was still used today even thou is is so expensive.

That all being said, some other metals with similar properties are PGM's, so when Silver goes higher in price than Rhodium, Palladium, and Platinum, you'd have a good chance.

Fortunately, the price-insensitivity of hard products due to the small amount of Silver needed versus the cost of all the rest of the process means that even with the impending explosion in the price of Silver, your film will likely no more than double in cost.

Same for all the massive impending requirements for Silver solders (as lead solders are finally phased out for all those electronics pick-and-place robots in Asia), all the nano-silver uses become commercial, and all the unique silver applications they're finding daily start making it into the mainstream consumer products.

Strange that all this 'bubble' of huge new industrial uses for Silver (only) are coming down the pike at the very time the big leveraged world banks are writing massive not-backed-with-real-silver "paper promises" (naked short futures contracts) and compounding derivitives on top of them, and yet the price hasn't gone up more than about a 20% annual lately. I'm sure I'm not the only engineer reading all these discoveries for Silver and seeing the mushroom of future demand coming?

Latest BIS report says there is something like an order of magnitude more silver 'sold' on paper than what will be in existence anywhere refined on the planet in the next year. Wonder exactly what that very first bubble of commodity "defaults" will do to the price of Silver, since the "official" price only reflects the price they set with those un-backed pieces of paper?
Sound anything like the mortgage bank bailout and crash? Only this could affect the 1000-times-larger currency bank markets?

The 'real' price of actual silver - the metal kind - is generally found at market, like eBay or your local coin shop...if they have any...mine hasn't for a year, gotta go online.

From the tiny size of the silver market left over for 'investors' (or just savings for little fish like me), it looks like a single Billionaire could take his money out of tanking Bond markets and buy up the entire world's production of Silver "just to be safe" - and your x-ray film use would then see a true need for another material, fast.

Saw a timely link in a newsletter last night that caught my eye...Comet Holdings YXLON, reportedly a leader in industrial X-Ray non-destructive testing...as well as Metris, owner of competitor X-Tek that specializes in production-line x-ray electronics inspection.

Their systems include filmless CT systems similar to the new digital-camera like x-ray systems your dentist likely now uses for instant viewing of your teeth on a laptop next to your chair.

You may well be in the market for one of these industrial versions to avoid film entirely.

I believe they use an amorphous silicon detector, CMOS, and link to a computer nearby running image-capture software. You can even adjust the resolution, brightness, etc dynamically during inspection.

Medical Radiography has gone away from silver film to CR technology, whereby a plate of rare earth doped Aluminium Oxide is exposed to the rays and forms a latent image which is read out by scannining it with a red laser. The light given off as the laser scans the plate (raster style) is measured digitised and put into memory. The memory is read out by computer as an image.

The image is formed at lower dose than Ag halides, is linear with dose and has a much higher dynamic range allowing useable images at over and under exposure. The doctor can window the image for brightness, contrast and gamma so that it looks identical to an image made by silcver based film. The Computered image may be looked at by a radiologist on the screen or may be made into a Xerographic copy (also not silver based) on film like plastic sheet.

There have been other technologies including Xerography which does not use silver halides

There is no reason why such CR technology cannot be used for industrial radiography, except for the set up cost of the CR plates and reader. The other advantage is that of being a dry process for getting the image.

20 years ago the company I worked for bought TV cameras of the old beam scanning type (not CCD or CMOS) from a company that made them mainly for viewing down drains etc. While visiting their works in Bodmin they showed me a rig they were building for airports in which a person stood in a cubicle (in the dark?) with X ray source one side and a special plastic film on the other which glowed when hit by x-rays. A TV camera then relayed the image to a remote operator to check for weapons etc.. Obviously you cannot wait to process film in this application. They admitted their system needed more X-ray dose than was legal in most countries.

So how do the current luggage scanning systems at airports work, with their live images?

With digital systems.

Digital system are capable of much higher sensitivity than the fastes of films and such a device is available today

They are trialling an digital X-Ray eye undressing machines in some Australian Airports. The exposure is short, intensity is low as is the energy so that it does not penetrate below the skin, but I bet it is as good a candidate for causing skin cancer as the longer exposure to higher intensity UV in solaria.

They are contavertial, and permission of the viewee must be gained. I wouln't be surprised if some countries do it without you knowing. The digital images from the machine could be good entertainment at Custom's staff parties.

If a push comes to a shove I prefer to strip to my undies, that way you know what just one person has seen. In that respect it would take a 1000 words at a party to descibe what funny anatomy thay had seen compared with one image taken from the machine to the party illegally