Photographic printing

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Photographic printing is the process of producing a final image for viewing, usually on chemically processed sensitized paper, from a previously prepared photographic negative, from a positive transparency or slide, or a digital image file.

[edit] Printing from a Negative

The process consists of three major steps, performed in a photographic darkroom or within an automated photo printing machine:

1. Exposure of the image onto the sensitized paper using a contact printer or enlarger
2. Processing of the latent image through a multistep chemical immersion process.
   1. Development of the exposed image. This step reduces the silver halide in the latent image to metallic silver.
   2. Stopping development by neutralizing, diluting or removing developing agent.
   3. Fixing the final print by dissolving remaining unexposed/undeveloped silver halide from the light-sensitive emulsion.
   4. Washing thoroughly to remove chemicals used in processing, protecting the finished print from fading and decay.
3. If made on glossy paper, ferrotyping to enhance the reflective gloss.
4. Optional Toning of the print through additional chemical processes that replace all or part of the reduced silver in the image with other pigments.
5. Texturing and drying of the final print.

Optionally after fixation, the paper is treated with a hypo-eliminator to ensure complete removal of the fixative, which would otherwise compromise the long term stability of the image. In processing color prints additional steps are added to form the color pigments from precursors in the different color-sensitive layers of the emulsion.

[edit] Printing from a Slide or Transparency

Printing from a slide or transparency is similar to printing from a negative except that additional processing steps are added to form a reversal print.

Initial development of the print results in a negative image. This development is not followed by fixation, but rather the reduced silver of the negative image is chemically removed from the paper. Since the paper has not been fixed, the unreduced silver halide remains in the emulsion. To form the positive image, the paper is then exposed to light, which creates a latent image in the unreduced silver halide coating. This latent image is developed and fixed to form the positive image.

[edit] Printing from a Digital image

Digital photography allows, even encourages people to take more photographs. Most of these photos will be viewed on computer monitors, televisions, Digital photo frames, and online Photo sharing sites. Some will be printed at home using Inkjet printers and more specialized Photo printers. For true Photographic prints, image files can be taken to “1 hour” photo finishing locations which have digital minilabs or uploaded to Online photo finishing sites which then mail you your prints. Some Chain stores combine these services allowing you to upload your pictures and specify which local store you want to pick the prints up at one hour later.

[edit] References

[edit] See also

• List of photographic processes
• Film developing
• Gelatin-silver process
• Enlarger
• Contact print
• Photographic print toning
• Photographic paper

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