Light-sensitive silver halide crystals are built into the film emulsion during manufacturing to capture light images on film. During processing, the silver halides are converted into metallic silver and then the color couplers in the film react with the oxidation products of the developer to form a dye. The silver is removed from the film during the fixing and bleaching stages of photographic processing in the film laboratory. Once the silver has achieved its purpose, of capturing the visible light during exposure, it becomes a redundant by-product and is subsequently removed. If some of the silver is allowed to remain in the final print, it provides enhanced blacks and higher contrast. 

Richard Smith explained: “Both CFI and Fotokem have what you would call an ‘alternative ENR process.’ Because of the constraints of our existing processing tank setup, we are unable to put a true ENR tank inline. We would do that if we had the tank availability, but [as it stands] we would have to reconfigure the entire processor. In normal processing, the film travels through the color developer, stop, first fix, bleach, soundtrack application, wash, second fix, wash, stabilizer and then to the dry-box. In an ENR-type re-silvering process, the B/W developer is introduced after the sound application [or after the bleach] and before the second fixing bath.”

“To differentiate between the two, with the Enhanced [Silver Tint] process, we leave 100 per cent of the silver in the print, resulting in an infra-red reading near 240. But with Standard Silver-Tint, we can remove a portion of the silver, yielding an infra-red value between 165 and 175. Standard Silver-Tint has higher contrast, blacker blacks and desaturated colors compared to a normal print, but not to the same degree as the Enhanced Silver Tint.” (Smith, 2023) The final decision to use either the Enhanced process or the Standard Silver-Tint process was ultimately made by the CFI client.

Close coordination between the laboratory and the production companies’ representatives was required to achieve the preferred degree of this “Silver Tint”. In some cases, tests prints were made, to satisfy the client. In performing this process, a technique referred to as “bleach bypass” was employed, which involved skipping the bleach bath, either completely or partially, by rethreading film in the racks within the film developing machine to provide less (or, no) time within the bleaching section of the process. CFI always strongly recommended that their clients only utilize this modified process for the final release prints, rather than applying it to the original camera negatives, Interpositives (IP), or Duplicate Negatives (DN). Although the bleach-bypassed original negative, IP or DN can be reprocessed to eliminate the skip-bleach effect, this does involve redeveloping the film through the entire process a second time. This redevelopment is always a potentially dangerous operation posing the possibility of damage to the original camera negative, IP or DN elements and has always required the customer’s prior approval.