Basic Characteristics of Film and Paper

FILM

  1. COLOR OR SPECTRAL SENSITIVITY - Film is either Panchromatic (Pan Film) or Orthochromatic.  Panchromatic, means that the film is color sensitive in relation to the Black, White, and Grey tonal range.  Orthochromatic, is a special sensitivity to a color or colors.
  2. CONTRAST - High contrast is when the image contains mostly blacks and whites but few grays.  Low contrast is when the image contains mostly gray values and few blacks or whites.
  3. LIGHT SENSITIVITY - Film speed as expressed by an ISO (International Standards Organization) number.  400 Speed film is a general purpose film used in average light conditions or out of doors.  Higher ISO film speeds like 800 or greater are for low light light conditions found mainly indoors.  Lower ISO film speeds like 200 or less are for use in bright sunlight or controlled studio lighting. 
  4. GRAIN - The size of groups of silver halide crystals.  The grain can be easily viewed with the help of a grain focusing device while the negative is being projected with the enlarger.   Fine grain films will register higher contrast, higher resolution, and a lower speed. 
  5. RESOLUTION AND ACUTANCE - The ability of a film to register detail and sharpness.  The greater the ability to register this sharpness the "higher" the resolution and acutance.
  6. SIZE - Standard film sizes are 35mm, 2 1/4 Roll, and 4"x5" sheet (Larger sheet film sizes are also available)
  7. LATENT IMAGE - Potential image, invisible, after film has been exposed to light but before the image has been chemically processed and developed.  The first step in the chemical process of developing an image.

PAPER

  1. COLOR OR SPECTRAL SENSITIVITY - Most Black and White papers are orthochromatic to allow them to be handled under "safelight" conditions.
  2. PAPER BASE AND COATING - RC or Resin Coated paper is encased in a layer of polyethylene (plastic) which results in chemicals not being readily absorbed into the paper permitting reduced processing times and chemical consumption.  FB or Fiber Based paper has no resin coating.
  3. IMAGE COLOR - Black and white paper base and emulsion both can contribute to the image tone having a warm or cool appearance.
  4. SURFACE LUSTER - The texture of the surface of the paper.  Glossy paper will render the most brilliant and sharper appearing image.  Heavier textured papers tend to soften the image.
  5. SPEED - Sensitivity of paper to light.  In relation to films, papers are far "slower" or less sensitive to light.  The term "rapid" in relation to papers is a reference to the speed at which an image appears during chemical developing.
  6. CONTRAST - Photographic papers are manufactured as a "fixed" contrast or a "multiple" contrast paper.  ILFORD uses the term "Multigrade", while Kodak uses the term "Polycontrast" to refer to their multiple contrast papers.  Higher numbers like "5" will produce a higher contrast print, while lower numbers like "0" will produce gray or lower contrast images.  Multiple contrast papers may be adjusted by the use of a set of numbered filters.  The filters cannot be stacked to produce a higher contrast.   A #2 and #3 will not equal a #5.  Only a #5 will do.
  7. WEIGHT - The thickness of the paper base.  Standard choices are single weight and double weight for FB papers while RC papers are usually referred to as medium weight.  In actuality they are single weight papers with the added thickness of the resin coating.
  8. SIZE - Standard sizes are 5"x7", 8"x10", 11"x14", 16"x20", 20"x24", 30"x40", custom sizes and rolls in varying widths and lengths.
  9. LATENT IMAGE - Just as with films most photographic papers are "developing out papers" meaning that the image does not appear until a chemical developer is applied.   Most "print out papers" or P.O.P. are no longer manufactured.  These papers contained the developer in the paper and would react immediately to light.