Ilford black-and-white photographic film.

User avatar
Posts: 13108
Joined: 24 Jan 2010, 23:23
Location: brings.slot.perky

Re: Ilford black-and-white photgraphic film.

Post by ChrisGreaves »

stuck wrote:
20 Dec 2021, 16:17
The light sensitive emulsion of every film, B&W or colour, has it's own characteristic response to light ...
OK. I am still back in Mr. Crosby’s chemistry class 1961-63 where we learned that silver nitrate was a molecule, and was used in photographic film. And I believed that the molecules were either au naturel or changed by exposure to light. Even in those days I saw things in binary. Film crystals were either on or off. I had no idea that the emulsion could exhibit different characteristics. That changes everything.
... MS Paint is not a photo editing application...
Quite so, but MSPaint is about the limit of my ability to play around with colours! If it wasn’t for my signature this month, I would not have been brave enough not to ask!
ChrisGreaves wrote:
20 Dec 2021, 11:51
...Film then provides a much finer resolution of light values than can digital...
No, that's not been true for a long time now.
Fair enough. Perhaps it was true back in 1990 when my photograph-mad pal Rick tried to explain the difference to me.
The amount of detail, i.e. the resolution, that a digital sensor can capture is determined by the size / number of pixels on the sensor. It's a bit of an over simplification but digital SLR cameras began to have better resolution that film once the sensors got to over 7 megapixels (MP).
OK. Of course, I see the advertisements for so-many mega-pixels as advertising bumf, meant to sway uninformed amateurs like myself.
And I am so old-fashioned that I still think of a camera as an array of elements, each with a soldered wire. Times have changed, and it is all printed circuits now, atoms sprayed onto surfaces. In 3_D yet!
If you want a good starting point on digital photography try these tutorials:
And just like that a whole afternoon’s VBA programming goes down the tubes.
Thanks Ken! :sigh:

And now back to
Don’t let a good crisis go to waste

User avatar
Posts: 6932
Joined: 25 Jan 2010, 09:09
Location: up North (but it's not that grim)

Re: Ilford black-and-white photographic film.

Post by stuck »

ChrisGreaves wrote:
20 Dec 2021, 20:35
...the emulsion could exhibit different characteristics...
Different shapes and sizes of silver nitrate crystals, different distribution of the crystals in the emulsion. All sorts of things combine to give different deposition of silver in the negative. Rinse and repeat when printing the negative as a positive print.
...Perhaps it was true back in 1990...
Yes, but not by the early years of the 2000s.
...many mega-pixels as advertising bumf, meant to sway uninformed amateurs like myself...
Yes, buyer beware, do lots of homework before you splash cash.