Most durable photograph recording medium : Photosensitive Glass

Most durable photograph recording medium : Photosensitive Glass

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Mustafa Umut Sarac submitted a new resource:

    Most durable photograph recording medium : Photosensitive Glass - Most durable photograph recording medium : Photosensitive Glass

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  2. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    U.S. Pat. No. 2,515,937 page 1

    paper 1 attached 2515937
     

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  3. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    U.S. Pat. No. 2,515,937 page 2

    page 2 U.S. Pat. No. 2,515,937
     

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  4. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    U.S. Pat. No. 2,515,937 page 3

    U.S. Pat. No. 2,515,937 page 3
     

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  5. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    U.S. Pat. No. 2,515,937 page 4

    U.S. Pat. No. 2,515,937 page 4
     

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  6. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    U.S. Pat. No. 2,515,937 page 5

    U.S. Pat. No. 2,515,937 page 5
     

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  7. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Gaffer® Photosensitive Glasses

    For the first time, Gaffer Coloured Glass offers photosensitive glasses suitable for use as a casing glass for the studio glassblower. Although noble metal photosensitive glasses were developed by Dalton and later Stookey, at Corning, during the Second World War (and kept under wraps by the US government until the war ended), they were never much exploited by Corning. They offered them largely as a novelty glass in the 1950’s and 60’s.

    Gaffer Glass has reworked the original recipes, in order that the glasses will be compatible with typical soda lime glasses used by the studio artist. Particular attention has been paid to aligning the properties of expansion, viscosity and durability.

    Properties and Application
    Gaffer photosensitive glasses can be used in the same way as any other casing glass, either as an inner or outer casing, or as an interlayer. They are soft, and easily worked. In order to exploit their properties, however, these glasses must be able to be exposed to ultraviolet light in the finished piece. Think of the glass rod as virtually like filmstock. It must be kept in the tube we supply until ready to use for blowing. After finishing a blown piece, that also must be kept in the dark until it is ready to be masked and then exposed and developed.

    Although photosensitive glasses are not anywhere near as sensitive as film, the ambient levels of UV light in a room will still be sufficient to “spoil” the glass after a day or two. Avoid direct sunlight. A “spoiled” glass, however, simply becomes an ordinary gold ruby or silver yellow, on being reheated, so is not completely wasted.

    Exposure
    The exposure of photosensitive glass is in many respects similar to that of ordinary photographic material. It differs mainly in the fact that exposure requires UV radiation, and usually requires considerably more time. The wavelength of light required is important, being between 300-350nm, and preferably peaking at 320nm. Sunlight can work, particularly at sunburn strength, but the results are variable. More consistent results are obtained by the use of commonly available fluorescent suntan tubes. Philips TLK 40W/10R low pressure mercury vapour fluorescent tubes are ideal. They are available in 600mm (2 foot) lengths. Other suntan tubes offer similar specifications. They should all be branded UV-A.

    Note: Not all UV lamps are the same. Some lamps for instance, used for curing silk screening dyes or photo printing etc. may have the wrong wavelength for this application. Exposure at a distance of 100-150mm (4-6 in) for about 20-40 minutes is sufficient for most effects. An even exposure of a vessel can be achieved with an old record turntable. With the gold ruby glass, short exposures will give blue through to purples; longer exposures will give a true ruby. Increasing exposure with silver based glasses results in an increasingly deeper and stronger yellow colouration. The colours produced, and the density of the hue, depend on exposure time and intensity, but importantly, also on development temperature, and time. After UV exposure, only a “latent image” results, which is not visible. Development by heat is still required.

    UV Resists.
    Anything which resists UV light can act as a resist or negative. For photographic resolution the most efficient material is adhesive polyester as a reverse negative, available from specialist photographic suppliers. However, anything which can stop UV is suitable. Felt tip pens, Letratone, bromides, masking tape etc. are all effective to varying degrees.

    Development
    Unlike ordinary film, which requires chemicals to develop the image, photosensitive glasses simply require heat. For silver glasses the “latent image” will develop in 3-4 hours at 475-525oC (886-976oF)
    For the ruby glass a higher temperature of 520-575oC (968-1058oF) is required over a similar period of time. The higher the temperature, the quicker the development. The term “latent image”, refers to the fact that simply exposing the glass to UV light will not make visible the colour. The colour centers are “latent” until developed by heat. If the glass is slumping, then simply lower the temperature, and take more time for the image to develop. Only by heating to the correct temperature range, for long enough, will the latent image reveal itself or strike.

    As with exposure, short heating times, and low temperatures, will produce blues and purples with the gold ruby: high temperatures for longer periods promote the true ruby shade. The silver yellow deepens in hue with long exposure and development.
     
  8. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    I remember 30 years ago there was a glass product that you can make negative masks out of it. If I remember correctly, you would use high intensity light to expose the glass and an image would be created for the mask. The glass then can be cleared with hot water to be reused again. Does anybody remember such a product?
     
  9. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Foturan Photosensitive Glass

    Foturan is a photostructurable glass ceramic (PSGC) manufactured by Schott Glass Corp and distributed by Invenios. Foturan is used as a MEMS and MOEMS substrate. Microfabrication in Foturan is achieved through patterning by a pulsed UV laser, a follow-up heat treatment step, and chemical etching. In Foturan, the exposed areas experience a selective phase change in which the native amorphous glass phase converts to a crystalline lithium silicate phase. The degree and type of crystallization are both responsive functions of the irradiation and thermal processing procedures. Under high exposure, the crystallized areas etch up to 30 times faster than the unexposed material in HF, with the etch rate varying with irradiation dose. Because Foturan is transparent at visible through IR wavelengths, direct-write XYZ exposure with a pulsed laser can detail complex 3-D structures within the Foturan material. Devices made from Foturan may be glass, a glass-ceramic composite, or ceramic, with the final material composition depending on the irradiation and thermal processing procedures. Excellent aspect ratios (>30:1) have already been demonstrated in Foturan.

    At Invenios we make 3-D MEMS structures by implementing cost-effective manufacturing solutions that produce consistent results with a resolution measured in microns.

    Invenios Foturan Resource Guide: Selected Articles about Photostructurable Glass-Ceramics

    2004 Direct ultrafast laser writing of buried waveguides in Foturan glass Stephen Ho and Peter R. Herman, Ya Cheng, Koji Sugioka, and Katsumi Midorikawa


    2002 3D microstructuring inside Foturan glass by femtosecond laser Ya Cheng, Koji Sugioka, Masashi Masuda, Koichi Toyoda,Masako Kawachi,
    Kazuhiko Shihoyama, and Katsumi Midorikawa


    2005 Holography in commercially available photoetchable glasses Michael Kösters, Hung-Te Hsieh, Demetri Psaltis, and Karsten Buse


    2006 Integrating 3D photonics and microfluidics using ultrashort laser pulses Ya Cheng, Koji Sugioka, Katsumi Midorikawa, and Zhizhan Xu
     
  10. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    http://glassmusings.blogspot.com/2010/02/photosensitive-glass.html

    Photosensitive Glass
    Here is a picture of an interesting process involving hot glass (blown) work. This could also apply to fused glass work although I haven't tried it.
    View attachment 58553

    View attachment 58554


    This piece is a blown platter that is about 16" in diameter. The intent was to blow a rondel, a round platter that doesn't really have any dips in the center and almost perfectly flat. That is one of the ways they made window glass in the "good old days". Anyway, this one is pretty good for me. There is a slight depression in the middle which is about half an inch deep. The interesting part of this is that you use a special glass color which is clear, but photosensitive. Thus it does need to be kept in a special wrapper until you are ready to use it. You blow the blank and then anneal/cool it. The annealer shouldn't be opened much as the piece is light sensitive and will pick up some darkening, however it is a very large exposure time.



    The photo above shows the blank after it came out of the annealer and ready for its exposure. I took a bunch of egyptian symbols as well as a photo of me and a colleague on horses at the Great Pyramids at Giza. I just taped these on the glass and even used a Sharpie to write my name and date on it. We had to work in a dark room with a safe light, just like old fashioned black and white photographic dark rooms.

    This was then taken outside. A very strong ultraviolet light, the sun being a great source is needed to expose the blank, just like a photograph. We left it outside at high noon for 45 minutes as there was some brief clouds. Normally 30 minutes in bright sun should be sufficient.

    This is then placed in a cold annealer, brought slowly up to working temperature (around 1100 degrees), and then annealed again. This sets the image on the blank. You can see in the top picture the color difference. There is an interesting color cast to the developed image and overall blank. The original blank was a very pale blue, and this developed piece is a medium amber color. It would take a lot of practice to figure out just how to make use of the coloring.

    Overall, I was impressed with the detail you can obtain using this process. I don't think I'll do it a lot, as it does require special glass and a means to expose it, but it sure is fun to contemplate.
     
  11. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Gaffer Glass blows these bowls or whatever you want with their photosensitive glass formula. Look at the above attachments.
     
  12. jvo

    jvo Subscriber

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    darn

    my 1000 f degree oven is on the fritz, otherwise, i found this interesting!

    jvo
     
    Last edited by a moderator: Nov 12, 2012
  13. john.penman

    john.penman Member

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    Thank you Mustafa for a fascinating article. Iv'e been using Gaffer photosensitive glass
    in my blown glass work for a few years now. It is definitely a rarely used material.

    I live just down the road from Gaffer Glass and apparently I'm the only one who buys it.
    They only ever made one batch of photosensitive and I've just bought the rest of what they had left.
     
  14. ic-racer

    ic-racer Member

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    I guess it is how one determines what "durable" means. Glass is pretty fragile, compared to the typical film base.
     
  15. snapguy

    snapguy Member

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    Gaffer tape

    Gaffer Video Tape lasts a lot longer and you can use it to affix photos to the wall when you want to copy them.
     
  16. cliveh

    cliveh Subscriber

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    Can it survive a nuclear strike or large meteor earth collision? If not, it is no more durable than a photographic print produced just before the disaster.