Defective negatives

[JohnF]

Thanks for all the responses.
All shots taken with the 150 mm lens but the last was at a smaller subject distance with a longer bellows, supporting MartyNL’s theory.
I have made some preliminary tests in the dark and revealed three pinhole light leaks of a not insignificant size which I am taping it seems with some success.
The bellows were sadly creased on one occasion when the camera was closed and the leaks seem to emanate from these areas. I have exposed quite a lot of film with no problems until this week.
I will double check the fitting of film holders and lens board and then plan a test including one sheet with a dark cloth over the camera prior to dark slide removal and some with no dark cloth.
I was surprised that having digitised the negatives, I was able to rescue the shots in Lightroom with some judicious use of the brush, linear and radial gradient selection tools, although it took some time

[bob carnie]

Looks like light leak from processing .

[Vaughn]

I am not sure, Bob. The rebate of the long side looks too clean for leaks during processing. <edit>

There appears to be a shadow cast by the rail holding down the film along the long side...less fogging right along the image's edge where the leaking light did not hit. Most visible on #4 along the bottom edge.

[John Layton]

...can see shadows of bellows pleats in that final image? Pattern larger with greater extensions? Same lens and lens board? Hmmm...maybe remove the film back - look into the bellows from the rear of the camera as you shine a bright light around the perimeter of that lens board. Might not be sealing adequately.

And/or - not familiar enough with your camera to know if your bellows is removable - but if so perhaps the front bellows attachment frame is not sealing properly...and opens up more when the bellows is extended?

At any rate...the flashlight test around the front should tell you - but watch carefully to see if the problem exists at the lens board to standard frame juncture, or to that between the front bellows frame and the flange into which it fits.

(hmmm...you said new bellows, which might still be a bit stiff and therefore exert more pull on those joints?)

[Fred L]

...And/or - not familiar enough with your camera to know if your bellows is removable - but if so perhaps the front bellows attachment frame is not sealing properly...and opens up more when the bellows is extended?...

had a Rosewood Wista DX and afiacr, the bellows were glued in, so not removable. Kinda miss the camera but not shooting 4x5 much any more. The bellows did need judicious use of tape and/or liquid tape for the one or two pinholes it had.

[JohnF]

Reporting back from my first post having sealed off all pinholes in the bellows and ensuring the Stearman tank was carefully sealed while in the changing bag. FP4+ at ASA 80, developed in 1:31 Ilfotec HC for 7 mins. Yellow filter. 20 Deg C
I came across a digital thermometer I had not used in a long time, having relied on an analogue one. Side by side, the analogue was reading 2 deg C higher than the digital one. Using the digital readout, I fancy the negative is punchier with the higher developing temperature of the digital thermometer, and no light leaks!
The image is of my back garden from our garden room with scaffolding to facilitate installation of solar panels showing-it was raining heavily first thing this morning!
Thanks for all the help

[Vaughn]

Excellent!

Many of the dial thermometers are designed to be calibrated occasionally...something I did often with the uni's dial thermometers...basically grip the sensor rod with pliers and turn the head until it matches the temp of one's baseline thermometer (in my case, a Kodak process mercury thermometer). They also tend to fall out of calibration.

[JohnF]

Thanks, Vaughn. I found a nut on the back of the analogue dial. Anchoring this and rotating the dial, I turned it to read the same as the digital thermometer.
Scaffolding now removed!