film holder (double dark slide) problem

[tonyowen]

167481

I seem to have a problem with one side of a 4x5 Fidelity Elite DDS
The negative (paper) mage attached shows white marks that are peculiar to one side of one DDS.
Are they the results of pin-holes, dirty slider or what?
The paper was cut from an 8x10 sheet and the other three portions are without similar marks.
Question:- how to check slider - nothing untoward is visible on either face of the slider
Question:= how to clean slider?

regards

Tony

[Steven Tribe]

Looks like material fibre debris to me - the debris is somewhat grouped.

I basically use only book film/plate holders which are easy to clean. Fidelity types look pretty difficult to open. Perhaps you could clean the concealed light seals by frequent in and out movements of the dark slide followed by "dust" removal from the slide. When the other side of the Atlantic wakes up, you will probably get more insightful suggestions!

[John Kasaian]

Tried the flashlight in a darkened room test, yet? That should rule on your pinholes in the dark slide question.

As for the bottom portion---?
It does bear an uncanny likeness to the coastline of the Isle of Lundy.
Perhaps this is being caused by poltergeist loyal to William de Marisco haunting your film holder?

[tonyowen]

As for the bottom portion---?
It does bear an uncanny likeness to the coastline of the Isle of Lundy.

Haven't used flash light but have held it up to the sun and powerful light.
'Lundy' is actually a rocky outcrop on the beach in Bull Bay, Anglesey - I was trying to photograph the clouds hence the high angle viewpoint

regards
Tony

[Doremus Scudder]

If you've held the darkslide up to the sun and see no light coming through, I would tend to think that that's not where your problem lies. Has this happened more than once with this holder?

The marks sure look like dust or dirt on the surface of the paper at the time of exposure. Check the light trap to see if it is dirty or disintegrating by running the darkslide through it several times and checking for carried-through material. If that's alright, then load up another piece of paper in a clean environment and test by leaving the holder sitting in bright sunlight (darkslide in, of course) for several minutes. Develop this sheet without exposing and see if there are any marks. If none, then your holder is likely just fine and you'll have to look elsewhere for your problem. Dirt on the paper inadvertently sometime before exposure is a possibility as is damage/contamination post exposure.

Best,

Doremus

[Jac@stafford.net]

It is dirt, debris.

The best way to clean holders is a blast of air, then careful brushing with Swifter duster cloths. Swifters can slide under the edges. They are virtual dirt magnets.

[tonyowen]

I think I've found the/a source of debris - there is gum residue on the dds 'case' that could become detached with the movement of the slider .
Is there a recommended means of cleaning the plastic surfaces?

regards
Tony