Is this because of light leaking？ Or overdevelopment?

[eraser]

I have had a wired problem in recent days, my negatives all came out with a strip ( light leaking or over development). All these problems come from similar places in my negatives ( as you can see from the picture I uploaded). I am using Chamonix F2, and SP-445 developing tank.
I initially suspected that there was something wrong with my lens and that there might be a lag in the shutter mechanism. Then I found it happened on both my 90MM and 150MM lenses. After that I thought it could be my developing tank, so I checked my SP-445 and tried again, it was still there
So I am here asking for help, has anyone experienced a similar problem? Or know the reason behind this?

Thank you for you reading

[Huub]

It is pretty hard to see on the picture you included, but do you mean that the top third of the negative is consistently lighther / less developed then the bottom twothirds? If so, that doesn't look like a light leak nor over-development but as not using enough developer to cover the negatives while developing to me... How many liquid are you using in your SP-445?

[eraser]

It is pretty hard to see on the picture you included, but do you mean that the top third of the negative is consistently lighther / less developed then the bottom twothirds? If so, that doesn't look like a light leak nor over-development but as not using enough developer to cover the negatives while developing to me... How many liquid are you using in your SP-445?

thank you for your reply. Sorry if the picture is hard to tell.
I'm sure the liquid is more than 475ml. And it's not the only time I met this problem, they all resulted in pretty similar: 1/4 lighter, 3/4 darker.

[Huub]

What you could try the next time is to put one negative upside down when developing. When the lighter side appears at the underside of the negative, it is pretty certain it will be camera-related. When again the upper sides underdevelop, you should test how much liquid you actually need to cover the negatives well. Just fill the tank with water until it covers and then poor the water into a measuring beaker. And you can use sheets of photo-paper to do this test as film is pretty expensive.

[maltfalc]

take a photo with the film loaded notched side first and tray develop it. if there's no light band, it was a development issue. if the light band is still at the same end of the fim holder, it's an issue with the camera or film holder. if the light band has switched to the other end of the film holder, your film got fogged at some point.

[sharktooth]

It could be some bellows sag is shadowing a portion of the negative, but if I was betting, I'd put my money on not enough developer in the tank to fully cover the negative.

[Doremus Scudder]

Can't be bellows sag; there would be no image making it to the film.

It's likely not development either; the line is much too regular. The tank does get inverted, doesn't it?

I'm betting on a light strike, likely from pulling the camera spring back away from the camera body when pulling/inserting the dark slide or from the camera back not fitting properly on the body. Check there first. Also look for bellows not properly seated and sealed (if your camera has removable bellows) or some other kind of leak.

And do pinch the camera back to the body with your free hand while pulling/inserting the dark slide.

Best,

Doremus

[joho]

I have had a wired problem in recent days, my negatives all came out with a strip ( light leaking or over development). All these problems come from similar places in my negatives ( as you can see from the picture I uploaded). I am using Chamonix F2, and SP-445 developing tank.
I initially suspected that there was something wrong with my lens and that there might be a lag in the shutter mechanism. Then I found it happened on both my 90MM and 150MM lenses. After that I thought it could be my developing tank, so I checked my SP-445 and tried again, it was still there
So I am here asking for help, has anyone experienced a similar problem? Or know the reason behind this?

Thank you for you reading

due to interest , I took a look at the photos you sent with the negs in question, at first view -now this is just my 2 cents. But it looks like two things to me -1-the film chases blinds where under some odd pressure and leaked light—2 air pocket in your flat tank processor . And that is if the standards of the camera where at null .

[eraser]

thank you all for replying, your answers are all inspirational
so i tried again today, with a very careful inserting movement on my Chamonix and one negative upside-down development like Huub said.
But very sadly, it comes the same, same place on negative again...
It makes me think if it comes from my camera, every time it comes from the same place on negatives no matter if I'm using different lenses or shift movement, very confusing to me.

[Chuck Pere]

Is the problem the same if the back is vertical or horizontal?