Love working with film I really do, but I really REALLY want to learn more about the developing side of things. I'm accumulating the stuff I need at the moment to start home developing black and white stuff, and I can follow instruction/youtube videos, but I really want a better understanding of the process and chemistry behind it.
Its a pain that none of my friends/family are into photography/film...:thumbsdown:
I saw a few books in charity shops recently that were devoted to film based developing etc, looks like some people are clearing their attics now they've gone digital. Must admit I got rid of my enlarger etc but I've kept my film developing kit, just in case.
The chemistry etc is actually very simple, the light turns the silver in the emulsion on the film black, but its unstable, so any more light e.g. if you pulled the film out of the casette the light would turn the remaing unexposed silver black. So whip the film out in a adrk room/bag and then go to work on it with the chemicals.
They combine with the exposed silver and form a stable compound once developed, fixed and washed etc.
Certain developers were produced to generate fine grain, some good edge definition (so pictures look sharper - actuance I think its called, hence trade names like acutol etc), some were created to develop fast films without excesive grain, all sorts of developers for all sorts of reasons/needs.
Of course you could underexpose the film then 'cook' it longer in the developer (creates a bit more grain) but it allowed photographers to push their films (hence the name push developing, also you could 'pull' a film i.e. deliberately overexpose because you didnt have a slow enough film.
(I think I got the over/under expose correct, it's been a while!!)
You could only over or under expose a whole roll, that is until colour technology was used in B&W film (Ilford XP1, which effectively had no Iso rating and you could change mid-roll if you wanted to) which used C41 chemicals and had great exposure lattitude.
Colour negative film is/was much less forgiving though, but still has a good exposure lattitude, however it couldnt be up/down rated i.e. used at a different Iso than its stated one (if memory serves me correctly), I think the colour mask on colour negatives messed this 'facility' up.
Colour Slide film which was based on B&W technology (as is digital) can be pushed or pulled and development times/temps adjusted accordingly. However slide film has poor lattitude and high contrast, so messing with development times/temps could be variable, although I used to push Kodak Ecktachrome (sp?) iso 200 to either 400 or 800 (1 or 2 stops) in the 70/80's quite succesfully.
Brings back some memories
HTH
Matt
