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View Full Version : Small white streaks on plates, what's the cause?



Ethan
16-Jul-2020, 18:47
205895205896

I shot these two plates of some friends this afternoon. I'm finally getting consistent results with my plates, but these photos have small white streaks on them as you can see. There is a lot of junk that has ended up in my fixer from not washing early plates enough before putting them in it, could that be the cause?

Thanks,
Ethan

Two23
16-Jul-2020, 19:10
Looks like comets. Usually a result of flakes coming off the collodion bottle.


Kent in SD

Ethan
16-Jul-2020, 19:16
Looks like comets. Usually a result of flakes coming off the collodion bottle.


Kent in SD

How would I prevent it?

Two23
16-Jul-2020, 19:30
Make sure there aren't dried flakes or particles on the bottle, especially around the mouth.


Kent in SD

cuypers1807
17-Jul-2020, 11:24
Comets are caused by collodion in the silver bath. Filter your bath more frequently and they should go away. You are more likely to get comets If you put the plate in the silver too early. The collodion has to set on the plate or else it will flake off and cause comets.

Ethan
17-Jul-2020, 12:26
how long do you let a plate sit before putting it in the silver? I haven't been very careful about that, so that could be my issue.

Two23
17-Jul-2020, 13:49
how long do you let a plate sit before putting it in the silver? I haven't been very careful about that, so that could be my issue.

For 4x5, depending on the temperature, the time is usually half a minute. I mostly go by sight though. I tilt the plate to see if there are tiny wrinkles starting to skin over the surface, sort of like what forms on soup or gravy but not as thick. I also will touch the very corner where I poured off the collodion--the "drip corner." if it's sticky it's too soon. If it's getting soft & mushy it's time to put it in the bath.


Kent in SD

alex from holland
19-Jul-2020, 13:50
Comets are caused by dust particles. Mostly fallen on the plate AFTER the plate is placed into the plate holder.
So make sure you are using a clean plate holder. After exposed take out the plate facing down the sensitive layer and NOT by turning the plate holder itself. While turning the plate holder dust can fall onto the wet plate causing comets.
And make sure your camera is clean at the inside!

cuypers1807
19-Jul-2020, 21:07
how long do you let a plate sit before putting it in the silver? I haven't been very careful about that, so that could be my issue.
After pouring the collodion back into the bottle, I dab the pour off corner onto a paper towel. As soon as it stops leaving marks, it is ready for the silver bath.