Reversal Processing - B&W Film to Positive
In this video, we show another different process where we achieved a positive result on a black and white film strip. Special thanks to Ale and Rennan from "O Retratista" for the chemicals provided for the video.
All information about the process and contact links are below.
Instagram O Retratista: / oretratista_alexrenan
Website to purchase chemicals from O Retratista: https://www.diafragma8.com.br/boutique
Black and White Film Development by Inversion (positive image)
When a photographic film is exposed to light, a latent (invisible) image is formed. This image only becomes visible after the development process.
In the normal development stage, the silver halides that were hit by the light and formed the latent image are transformed into black metallic silver. The halides that were not exposed remain sensitive, and for this reason, a fixing bath is necessary to remove these unexposed halides, transforming that part of the film into transparency. In this way, we have a final negative image because the part of the film that received light becomes dark, and the part of the film that did not receive light becomes clear (transparent).
In inversion developing, the film is developed normally, but instead of using a fixing bath, a bleaching bath is used, which will not remove the unexposed halides, but rather the halides that have already become black metallic silver, thus making that part of the film transparent. After this, the entire film is exposed to diffused light, thus fogging the entire area of the film that was not exposed at the time the photograph was taken. By performing a second development, the clear part of the film, which is now fogged by having received light, will become dark, resulting in a positive image.
Procedure
1) Development - Develop the film with Dektol (stock solution) at a temperature of 20 to 24 degrees Celsius for 8 minutes. Stir constantly for the first 3 minutes. From the fourth minute onwards, stir for 30 seconds every minute.
2) Stop - Stop development with any stop button for 1 minute. Stir constantly.
3) Wash - Wash for 2 minutes under running water.
4) Bleaching - Bleach for 3 minutes. Stir constantly.
5) Wash - Wash for 2 minutes under running water.
6) Whitening - Whiten for 3 minutes. Stir constantly.
7) Wash - Wash for 2 minutes under running water.
8) Exposure - Expose the film outside the tank, but still in the coil, under a diffused white light (we used a 20-watt LED lamp) at a distance of approximately 1 meter for 2 minutes on each side of the coil. We recommend doing this procedure with the coil inside a container of water to avoid possible stains.
9) Development - Back in the tank, develop the film with Dektol (stock solution) at a temperature of 20 to 24 degrees Celsius for 3 minutes. Shake constantly.
10) Stop - Stop the development with any switch for 1 minute. Shake constantly.
11) Fixing - Fix the film for 5 minutes. Shake constantly.
12) Wash - Wash the film for 5 minutes and let it dry.
Tests were performed with various exposures, and the one that resulted best was 1 stop above (overexposure) that indicated by the photometry.
The film used in the tests was Ilford Delta 100 and the camera, a modest Zenit 212k with a Helios 58mm lens.
VERY IMPORTANT: It is safe to perform this process with the following films: Kodak Tri-x, Kodak Plus-x, Ilford Delta and Ilford HP5+, obtaining extremely satisfactory results. If you use films other than those mentioned, perform a tip test to ensure the functionality of the process.
Source: O Retratista website