Here is another bit of information for film enthusiasts. Film characteristic curve or S-curve as sometime it is referred to. Please do not confuse this term with S-curve in composition. Have you use the Curves adjustment in Photoshop? Are you surprise that is it there?

Every film canister we buy has a Fact Sheet illustrating the characteristic curve of the film. Here is one for Ilford HP5 Plus, Page 5 of the sheet. http://www.ilfordphoto.com/Webfiles/2007321132461251.pdf

If you Google film characteristic curve, there are more advance discussion on this subject that I can cover on this thread. What I will cover here is what importance is the understanding of the curve to our exposure technique?

Here some basic information about the curve:

http://i217.photobucket.com/albums/cc75/nikonf2/scurve.jpg

Filmbase-Plus Fog Density – if you develop a film without exposing it, it will not be totally clear after development but some fog will be present so the exposed film will have some density.

Toe – this is the portion of the curve that will have the first detail for printing. A very important part of the curve.

Straight Line – this is the region of the curve where the details are clearly delineated or the simply stated the region of correct exposure.

Shoulder – this is the part of the curve where overexposure exists. Anything over the shoulder (no pun intended) will be overexposed.

How is this going to help my technique? Remember the TOE in the curve? When deciding what details are important in your photograph, placing the subject in the toe where you want minimum detail and below the shoulder will guarantee that it will be there after exposure.

Wow thanks a lot for sharing!
Yeah, it's the digital era, but sometimes I do wish I could have a chance do develop my own photos inside a darkroom. In our school's library, I saw a section where there are books on photography (the ones dated 1970's-1990's). I saw very very serious books about film theory and lots of scientific stuff. yeah, One day I want to learn all about those.
Anyway, again, thanks for sharing!

hi delfino,

any chance that this film curve can be translated to a curve in photoshop?

hi delfino,

any chance that this film curve can be translated to a curve in photoshop?

You can use Exposure to make your own film curves dude :)
It takes quite a long time to get the final product right cause you need to jump in between channels rin to get it right sometimes, and you need a calibrated monitor, both of which you have. :) I'll dig up the tutorial link and a 3rd party forum that has members churning out lots of great custom curves, even some that can be loaded into the presets of most dslr's.

Nino,

http://i217.photobucket.com/albums/cc75/nikonf2/curves.jpg

Here is a basic guide: Photoshop assigns 0 for absolute black and 256 for white. Start assigning 40 for the any shadow area you want details and 240 for white that you want to have details.

Here is a grey card illustration of how you would manipulate the photo. The first photo would have straight line (not illustrated). The copy of the graycard has been assigned the above numbers. You can then save the curve for use for any similar scene you want the curves for. I hope you can see the overall change in contrasts in the second photo.