Tap water leaving white spots on negatives
I have recently noticed small spots on negatives when scanned in high resolution. Many sites on the Internet suggest it to be dust. The number and consistency of the spots however make it unlikely to be dust. There are about 50 to 200 spots per negative, concentrated in groups, mostly towards the edges of the negatives. I am just not that careless when handling wet negatives.
A few other sources suggest chemicals in the water. This suggestion seems to provide a more plausible explanation. Photographic developer consists of various components. A developer that develops the image, a compound that softens and opens up the emulsion layer to allow the developer to penetrate and do its work, and a compound to balance the process so as to not allow development to proceed at a pace that cannot be managed.
When the processes of developing and fixing have run its cource, the film is washed in water to remove all remaining chemical compounds from the emulsion. And this appears to be where the spots are coming from. I used tap water for the washing process. The tap water penetrates the softened emulsion to remove the chemical residue left by the developer and fixer. But in this process some chemicals dissolved in the tap water gets trapped in the emulsion layer. These tiny chemical deposits blanks of f the scanner’s light source resulting in a white spot on the scanned positive image.
This would explain the consistency of the spots. A particle needs to be of a specific size the get trapped. Bigger particles wont pass into the gelatin while smaller particles will pass through. The flow of water through the tank may explain the higher concentration towards the edges of the negative. Water is directed downwards to the bottom of the tank where it spreads and moves upwards past the negative to exit at the top of the tank. This could also explain why there is a difference between the patterns of spots in film in a spiral at the bottom of the tank and a spiral at the top of the tank.
It should be pretty obvious from the way that I explain the problem that I am a total amateur. I developed a number of films in the late 80’s to early 90’s. Then progressed to digital. Now progressed back to film. I don’t remember having noticed these spots in films that I developed back in the 80’s.
I will amend the process that I follow. Develop -
Just wondering though. If the chemicals dissolved in tap water can leave a residue behind in a photographic emulsion, does it do the same thing in a human kidney, or does the kidney have a way to deal with these chemicals.
To the left is a building in the CBD of Johannesburg being demolished. The CBD of Johannesburg deteriorated but is in the process of being rejuvenated. Braamfontein, close to the CBD is a hive of activity. Maboneng started small but is expanding. More and more buildings are being bought, re-