Making your glass plate negatives, ones that would be repeatable and guarantee appropriate image quality is a true challenge. There are countless things that can go wrong and it involves uncountable hours of work. Why should we bother then? After all, we can easily buy large format negatives by Foma or Ilford; easy to use, durable, offering perfect repeatability and, in addition, panchromiatic. So, who would care about a glass plate negative?
Let me for the time being put aside the ideologica issues that can justify any amount of work. Let me also put aside the scaremongering about photochemical factories closing down and digital cameras being the only option; for the time being this doesn’t seem to be happening. The main reasons why I have decided to make my own negatives are quite different.
1. a different way to see the world
Almost all the negatives available these days are panchromatic. In other words, they see the world more or less naturally. Theoretically this is a great advantage, which however, limits us to seeing the world in a rather standard way, similar to all cameras and photographic materials. With a bit of luck we can still get orthochromatic materials (blind to the red part of the spectrum), but colour blind materials are just not available.
Things are very different with a self made emulsion cated on glass. Creating panchromatic materials is very difficult (the coating would have to take place in complete darkness), but to compensate for this we can use emulsions that are either colour blind or orthochromatic.
2. A different way to register light
Photochemical corporations devoted years of research to perfecting photographic negatives. As a result almost all their drawbacks have been eliminated. Modern negatives have anti-halation layers, special additions that limit the spreading of light within the emulsion. silver halide cristals responsible for their sensitiveness to light are grown under strict control that allows us to get cristals of perfect shape. All of these lead to the creation of images of perfect quality. Quality that is often too perfect to be interesting. The magical aesthetics of the old photographs have simply disappeared.
A hand made glass plate negative is covered with a much thicker layer of emulsion and lacks all the modern tweaks such as antihalation layers. Thanks to this, the image is created exactly in the same way in which it was created in the 19th century. It may be less perfect but then, it has so much charm.
3. technical issues
The contrast of old, thick negatives is frequently more suitable for historical processes than are the modern large format negatives of rather limited contrast. Of course, there are ways to increase the negative contrast, but there is always a limit to what can be achieved.
Things are different when it comes to emulsions you make yourself. First of all, you can use a variety of recipes that will influence the contrast which can also be controlled with the thickness of the emulsion layer (which translates into the amount of silver contained in it). This, together with the unique appearance of images copied from historically correct glass plate negative are trully priceless features for anyone who doesn’t want to work using digital enlargement.
4. available sizes
Despite the fact that many manufacturers have disappeared from the market, we still have a wide choice od films and sheet sizes. All of them are, however, more or less standard; I have never seen a factory made 7×17 inches negative. Sure, you can order negatives cut to size, but this is going to cost you extra and will mean waiting for your negatives to be delivered.
Once more things are different if you make your own negatives. With a bit of skill and practice you can coat almost any size and shape of a plate.
5. Financial considerations
I wouldn’t want to create an impression that making your own negatives is a cheap affair. It is not. The tests and perfecting your technology alone will swallow considerable sums and unlimited time. Materials used such as photographic gelatin or silver nitrate are not cheap. The biggest expenditure, however, is the time you need to spend on the process and time has a clear pecuniar value.
In practice all this means that buying a 13×18 negative will be much cheaper than making it yourself. Even if we value our work at the level of minimal wage, buying ready made negatives will be the cheaper option.
Things do start to look a little different with larger sizes, especially the non-standard ones. With an 11×14 sheet the cost of purchasing it goes up dramatically. On the other hand, with a bit of practice the amount of work needed to make your own materials remains more or less constant (at least as long as you keep the size reasonable). You do use up more material, but as I have already said this is not the biggest part of the expenditure. When it comes to negatives that are, say 30x40cm in size, the cost of buying them will be high enough to justify the long work in the darkroom.
The whole project becomes even more profitable if we use a camera whose size is not standard as buying such negatives would be even more costly.
To be perfectly honest though, the costs are not your best reason to start the adventure with making glass plate negatives. They are a cool thing to use because of the way they see the world and because of the way pictures taken with them look, not because their price might sometimes be a trifle lower. If this is your motivation, you’d better look elsewhere.