Twenty minutes ago I took a one litre bottle of fixer out of my fridge. It was about 4 degrees C. I sat it on top of the fridge to warm up while I went and mixed up the developer and loaded the film on a spiral, reminding myself in the process how much I dislike 35mm film - give me 120 any day.I just checked the fixer. It is now 25C. A 20 degree Celsius rise in temperature in just 20 minutes just in the ambient air.I think I should be processing C41...
Showing posts with label processing. Show all posts
Showing posts with label processing. Show all posts
Saturday, 11 February 2012
Thursday, 22 March 2007
Water quality
I mix up my photo-chemicals with filtered water that has been through a "Brita" cartridge filter containing activated charcoal and ion exchange resin, but i rinse my films with water straight from the tap. It's never been a big problem until this week.
There is a darkroom at my place of work, which is rarely used. I have started using it lately just to load film holders and such. This week I decided to develop some films.
1. The first film was a 120 roll of Delta Pro 400 shot in my Holga. I just used the tap water. When I turned on the tap the water came out orange. Apparently the pipes had not been used for a long time and were full of rust. I let the water run a long time and it cleaned up a bit.
"What the hell", i thought - its a Holga film. I went ahead. Development was unremarkable but the result was filthy and over-developed. The negs were almost black and covered with grains of grit. Washing the grit off caused some scratches. Total write off.
Question - do iron salts in water accelerate the action of the developer?
2. Next batch - 6 sheets of 4x5 delta 100 shot in my Speed Graphic. This time I mixed up the chemicals using water from the water filter in the tea-room. It has two big cartridges full of resins and things. However I rinsed in tap water.
Tray development, timed with music. Result was perfectly developed negs but again with grit from the tap water. Careful washing in filtered water and Photoflo removed this and I am happy with the end product.
3. Last film. having learnt my lesson I developed my final film for the week (a 120 of delta 400 shot in my Rolleiflex) totally in the filtered water, including the rinse - which was the Patterson inversion rinsing technique.
End result was the cleanest set of negs I have ever made. They didn't even need dusting to be printed or scanned.
So - I thought I'd tell my story as an illustration of the need to control water quality - but I'd like to know the answer to my question about iron salts.
There is a darkroom at my place of work, which is rarely used. I have started using it lately just to load film holders and such. This week I decided to develop some films.
1. The first film was a 120 roll of Delta Pro 400 shot in my Holga. I just used the tap water. When I turned on the tap the water came out orange. Apparently the pipes had not been used for a long time and were full of rust. I let the water run a long time and it cleaned up a bit.
"What the hell", i thought - its a Holga film. I went ahead. Development was unremarkable but the result was filthy and over-developed. The negs were almost black and covered with grains of grit. Washing the grit off caused some scratches. Total write off.
Question - do iron salts in water accelerate the action of the developer?
2. Next batch - 6 sheets of 4x5 delta 100 shot in my Speed Graphic. This time I mixed up the chemicals using water from the water filter in the tea-room. It has two big cartridges full of resins and things. However I rinsed in tap water.
Tray development, timed with music. Result was perfectly developed negs but again with grit from the tap water. Careful washing in filtered water and Photoflo removed this and I am happy with the end product.
3. Last film. having learnt my lesson I developed my final film for the week (a 120 of delta 400 shot in my Rolleiflex) totally in the filtered water, including the rinse - which was the Patterson inversion rinsing technique.
End result was the cleanest set of negs I have ever made. They didn't even need dusting to be printed or scanned.
So - I thought I'd tell my story as an illustration of the need to control water quality - but I'd like to know the answer to my question about iron salts.
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