tert said:
Now for my question (finally): To what size would a sharp (loosely defined) 35mm negative or 4R print (from 35mm) be enlarged to? How can i determine the extend to which i can enlarge my pictures?
TIA for the help
Best.
The maximum printable size from 35mm varies and is largely dependendant on the following factors.
Lenses:
The right choice of lens and it's optical and mechanical properties has a massive influence on the quality of the image captured to film. However you have to be aware of the diffraction limit as you stop a lens down and ideally for the highest quality work you should always shoot at the so called 'sweet aperture' which is the aperture that gives the best results for a given lens.
External vibration:
Wind, ground based vibrations from traffic, machinery etc, tripod, monopod and technique related issues have a direct bearing on the quality of image produced at the film plane and consequently on the emulsion.
Internal vibration:
Internal vibrations are caused by things like mirror slap, shutter bounce and the camera's ability to dampen such vibrations. A large heavy professional body has lower vibration and higher damping rates than a lighter body.
Emulsion flatness:
This is critical to producing really high quality images on film and the overal condition of the film pressure plate and guiderails play a vital role in ensuring the film is kept flat. Tensioning the film really assists in keeping the film as flat as possible but it's only possible with cameras that have a manual film rewind system.
Film Emulsion:
This is a really hoary chestnut. The finest RMS granularity isn't always the best for large enlargements as there's a secondary issue of grain shape and how it effects the perception of an enlargement. In an ideal world the grain size is minimal with a shape that isn't objectionable. However as we all know this will seldom be the case.
Film Processing:
Just how the film is processed and the age of the chemistry used, system cleanliness etc have a direct bearing on how printable the film will be. For B/W films the chemistry and method of processing is even more critical.
Printing:
The quality of the printing system and paper selection is paramount to making high quality enlargements. Most commercial minilab type printers (ie: Noritsu, Fuji, QSS etc) are not the best for sharpness, as they are optimised for a comprimise between speed and quality.
Paper: Not all papers are equal. The finest professional papers are capable of at least 10% or more resolution than the cheaper consumer grade papers.
Circle of Confusion:
This is the real crux of the matter with enlargements, and is the one component that is most overlooked by amateur photographers. As you enlarge a negative the circle of confusion increases in size and thus grain and sharpness deteriorate. However, as you increase the size of the enlargement the viewing distance is also increased and thus the apparent circle of confusion remains nearly the same regardless of enlargement size. However there are some practical limits to enlarging 35mm film. A high quality neg or slide should be able to print to 20 x 30 inches and give more than acceptable results when viewed from a distance of around a meter or more. However if viewed from the same distance as an 8 x 10" print you'll notice a marked difference in image sharpness.
Ultimately it comes down to what you the photographer are prepared to accept. If you scrutinise your images from a short distance then you should stick to a maximum of around 11 x 14" .. if however you are printing for wall displays then a poster sized print is about the practial limit.
Ian
) thing digital did for me was to enable me to blow my pictures much bigger than i ever did (or dared) with film. While the largest i went with film was 8 by 12, i did a couple of 12 by 18 prints with the d30 (and the resolution held up quite well for that size i would say). The ability to preview my pictures on the monitor aids me to decide whether a picture can be printed large. But with film, i would have to judge using either the negatives or 4R prints.