Weird Emulsion Artifacts

Hi, I hope all is well.

I’ve encountered an occasional problem when drying my 35mm film. Whenever I seem to use Clayton Wetting Agent, my film develops emulsion artifacts. They do not come out with rewashing and seem to be permanent. It also sometimes bubbles on the emulsion side as well. I’ve found that using a drying cabinet on its lowest temperature still leaves these marks. However, they do not happen when I use a distilled water final rinse + air dry (no cabinet). This only happens when I use Sprint or Clayton’s wetting agent at 1+200.

I have provided a photo on the negative through a loupe and a photo that was previously uploaded to this thread. The other individual has the exact same artifacts but nobody seemed to give a solid answer.

Let it air-dry. Film is obviously getting too hot.

What film(s)?

I would guess your water is extremely hard and that the minerals in the water (alkaline, desert?) are either scavenging emulsion as it dries, leaving a "pimple" of emulsion in the center of the water marks or simply depositing minerals in the center of the drying spot.

Can you locate a water report for your area to see what the PH and dissolved solid levels might be?

Being that you can use distilled water and not have the problem, why not continue using that? Even filtered water would be better IF you have PH and dissolved solids problems with your tap water.

I lived in Odessa, Texas for several years and the Caliche in the soil made the water as hard as diamonds. People who used evaporative coolers in their homes had to scoop out the solids from the coolers and replace the water pads once a year.

Try regular filtered water.

It’s happened with FP4 Plus, Fomapan 100, Delta 400. I think it’s been exclusive with cellulose triacetate.

Kino said:

I would guess your water is extremely hard and that the minerals in the water (alkaline, desert?) are either scavenging emulsion as it dries, leaving a "pimple" of emulsion in the center of the water marks or simply depositing minerals in the center of the drying spot.

Can you locate a water report for your area to see what the PH and dissolved solid levels might be?

Being that you can use distilled water and not have the problem, why not continue using that? Even filtered water would be better IF you have PH and dissolved solids problems with your tap water.

I lived in Odessa, Texas for several years and the Caliche in the soil made the water as hard as diamonds. People who used evaporative coolers in their homes had to scoop out the solids from the coolers and replace the water pads once a year.

Try regular filtered water.

Click to expand...

I was out of distilled water unfortunately and opted for tap. You might be on to something here. I just haven’t had consistent variables that cause this issue.

I think the problem is this: your tap water is fairly hard - which is quite normal. By using the drying cabinet, you're evaporating the water quickly, and this means that droplets of water clinging to the film dry up before they have the chance to run off. The edge of each droplet turns into a calcium deposit as the droplet shrinks due to evaporation. Gradually, the edges of the droplet pull back, leaving calcium deposits in the area the droplet covered formerly.

The black minus-density dot in the middle is a bit puzzling, but @Augustus Caesar may be onto something here in that final drop of water gets hot enough due to the dryer to do damage to the emulsion.

I'd expect that the high density (lighter) parts of the droplets will wash out if you rinse the film in a weak solution of acetic or citric acid and then wash again.

I also expect that the problem goes away if you squeegee the film before placing it in the drying cabinet, BUT squeegeeing film requires a suitable squeegee that is cared for meticulously and used sensibly. Damage done with an old and hard or dirty squeegee is irreversible...

The problem will likely also stay away if you just hang the film to dry in ambient temperatures, as you've observed, which is the most straightforward solution.