Unknown Artifacts on Rollei 4x5 Sheet Infrared 400 Film

[BobUK]

Do you use a torch with one of those powerful square LEDs?

The circle with a square in the middle reminds me of my LED torch.

Pictures below in focus and out of focus.

 

[mpirie]

Place the film corner lightly between slightly moist lips. When you open your lips the emulsion side sticks to one of the lips. Try it on an undeveloped leader of a roll of 35mm.
I used to do this when Cibachrome printing in complete darkness.

Yes, i've had to resort to using the moist-lip method in the past......i was referring to the fact that to avoid the impact of a manufacturing defect, the retailer expects me to use that method of identifying the emulsion side. when in reality, they should be replacing a faulty product.

Mike

 

[250swb]

Do you use a torch with one of those powerful square LEDs?

The circle with a square in the middle reminds me of my LED torch.

Pictures below in focus and out of focus.

It seems the most logical explanation so far, I was thinking 'maybe a torch' all along but your photo makes it look very likely given the pattern.

But yes, under exposing isn't compensated for by over developing the film, three stops plus reciprocity would be my guess (as others have said) for a Wratten #25. I would do a dark slide exposure test, pull the slide out in maybe three steps adding to the previous exposure step each time, the negative doesn't need to be sharp if the holder moves but ideally you want an expected plus, normal, and minus exposure when developed, if plus or minus turns out to be the better the 'normal' calculation was wrong.

 

[BobUK]

Yes, i've had to resort to using the moist-lip method in the past......i was referring to the fact that to avoid the impact of a manufacturing defect, the retailer expects me to use that method of identifying the emulsion side. when in reality, they should be replacing a faulty product.

Mike

Hello Mike.
Thanks for that.
I must admit I sometimes find it difficult to understand the direction of some messages in electronic mail.
It is not like being face to face where you can get the gist of a persons meaning, through their vocal style and facial expressions.
Nice one Mike.