What's these strange marks on 4X5 film? They come sometimes.

[Mike Sun]

I am a new LF users. I just find some strange black marks on film when processed.
No idea what will those marks be? how those marks caused.

I processed 4X5 film by paterson system. The problem comes out occasionally.
Those marks won't show up on 120 films.

Can any experienced guys kindly point out what i am doing incorrect? how to deal with the problem?

Thanks .

[ethanfg]

Mike,

I'm assuming you're using the MOD54 film holder with your Patterson tank? Could you provide any details on your processing method? Loading, inversion method, etc. The more detail the better. One thing to look for, are the marks on the emulsion side or not? If you orient the film with the notch code in the top right corner, the emulsion will be facing up. With BW film you can sometimes tell easier as the emulsion side will have a slightly matte appearance.

Ethan

[Mike Sun]

Mike,

I'm assuming you're using the MOD54 film holder with your Patterson tank? Could you provide any details on your processing method? Loading, inversion method, etc. The more detail the better. One thing to look for, are the marks on the emulsion side or not? If you orient the film with the notch code in the top right corner, the emulsion will be facing up. With BW film you can sometimes tell easier as the emulsion side will have a slightly matte appearance.

Ethan

Hi Ethan

Yes, MOD54 is the film holder i am using on paterson.

I load film in/out holder in changing bag.

Process is normal.
Dev. HC110
Rev. 10sec per min.

I hard to identify those marks on film surface. It doesn't look like any physical scratches on both side of film.

And, those marks are black on film. looks like "exposed already."

best,

[Neal Chaves]

Anytime the unexposed emulsion is subjected to stress, it reacts as if exposed to light. This can be from folding or kinking, pressure, or scratching. These exposed areas could be from loading and or unloading the holders or loading the processing equipment. Possibly fingernail scratches.

[Mike Sun]

thanks~~a lot~~

[Mike Sun]

Anytime the unexposed emulsion is subjected to stress, it reacts as if exposed to light. This can be from folding or kinking, pressure, or scratching. These exposed areas could be from loading and or unloading the holders or loading the processing equipment. Possibly fingernail scratches.

thanks Neal~~

[Neal Chaves]

You see the dense areas along the edges of the film, which are very common on the negs of even the most careful and expert workers, they are from the emulsion sliding along under the rails of the film holder while loading and unloading.

[Mike Sun]

You see the dense areas along the edges of the film, which are very common on the negs of even the most careful and expert workers, they are from the emulsion sliding along under the rails of the film holder while loading and unloading.

yes, ur instruction is helpful. I know what happened to the film. thanks~

[LabRat]

Looks like you were scratching top edge, probably while trying to lift film when trying to remove from holder... If you have trouble lifting film, I keep a piece of 35mm scrap film on a piece of tape stuck to film box to slide under film as a "lifter" if film does not come up with a fingernail...

Also noticed edges under film rebate are a little crooked which means film not evenly pushed into holder when loading, which can semi jam during operations... When pushing film in, touch one finger to the center of top edge, giving it a very slight side to side wiggle when pushing to find the least resistance...

Review film loading instructions...

Steve K

[Mike Sun]

Looks like you were scratching top edge, probably while trying to lift film when trying to remove from holder... If you have trouble lifting film, I keep a piece of 35mm scrap film on a piece of tape stuck to film box to slide under film as a "lifter" if film does not come up with a fingernail...

Also noticed edges under film rebate are a little crooked which means film not evenly pushed into holder when loading, which can semi jam during operations... When pushing film in, touch one finger to the center of top edge, giving it a very slight side to side wiggle when pushing to find the least resistance...

Review film loading instructions...

Steve K

thanks, Steve.