AboutDavid Barry Expertise I have a lot of experience in most traditional forms of photography, so I`m quite knowledgeable about things like camera types and formats, techniques, exposure, film types, colour, filters, lighting, standard colour and black and white developing and printing.
I do not make recommendations about brands or models, and I am not a camera technician so I may not be able to tell you what is wrong with your equipment if it`s not working .
I also know a little about digital photography and imaging with scanners and digital cameras, so ask me and I will answer if I can.
Experience Experience in the area
I have been seriously involved in photography for over 25 years, including about 4 years as a professional, as well as 2 years providing administrative service to government photographers, requiring interpreting photographers' requirements and trade technicalities for those unfamiliar with such.
I have successfully trained several beginners in photography, helping them to become competent in basic techniques.
Organizations belong to:
None at present, but have been in about 4 camera clubs, having won or had placings in 2 club competitions.
Publications:
A lot of my photos have been in educational / training manuals, books and some photography magazines, as well as 2-3 dozen images been on the Web so far.
Education/Credentials:
Completed 4-year diploma in professional photography technique at Sydney's Technical College
Awards and Honors:
3 placings and / or merits in camera club competitions.
Expert: David Barry Date: 9/29/2006 Subject: glass negatives
Question What are glass negatives and how do they work from years ago.
Answer Back in the very early days of photography, long before film as we know it was invented, photographs used to be made on glass.
In those days photographers often had to make their own glass photographic plates in their own home 'laboratory' or darkroom, by coating a light sensitive substance onto a sheet of glass which was then inserted into the back of the camera.
Often the plates would be approximately the size of an A4 size sheet of paper, maybe even bigger.
After taking the photo and developing the glass plate, the photographer had to make prints from the glass negative by laying it directly in contact with photo paper under a lamp (called 'contact' prints).
Some of the reasons that glass plates eventually became obsolete was that they were heavy, fragile (and so frequently broke and ruined the photo), and cumbersome to make, develop and store.
Also, the invention of film - which was lighter, more convenient and became more economical - further pushed glass negatives into history.
You might still see some glass negatives in museums, firstly, as an exhibit, and secondly, they may even still be used because they are the only existing record of some famous and not so famous events.
They basically work the same way as a film-based negative; that is, a light-sensitive emulsion is coated onto the glass plate (in a darkroom), and dried. Then the plate is somehow exposed in a suitable camera (probably not too many of those cameras still around). After exposure, the plate negative needs to be developed (again in the darkroom) in the right chemicals, washed and dried.
It is probably possible to actually still make crude glass negatives using high quality sheets of glass, some 'liquid photo emulsion' which can be bought from specialist photographic suppliers.
The glass plates could be developed easily enough in trays (in a darkroom) using appropriate chemicals.
But the main problem would be finding a suitable camera in which to safely hold and expose them. Today's sheet films are much thinner and use specially made holders in which glass negatives would probably not fit.
You might like to do further research on the internet and see if anyone has actually recently made and used glass negatives.
