some 'mistakes' I would like to learn from.
I've only been serious with developing for a short while and some 'mistakes' I don't understand repeat themselves. Maybe one of you know what happends:
-purple spots on the negatives after drying, even after extensive washing. (can the water I use to wash be to cold to be effective?)
-some negative turn out really flat, even the ilford text on the edges next too the exposed frames are nearly transparant, feels like the emulsion is completely washed of since it's not over exposing that creates this.
Maybe the next two questions are related to the filmback of my camera, It's an A12 for hasselblad.
-on many negs the left edges next to (and possible a bit on) the exposed squares are slightly darkened, seems there was light on it.
-The first and the last two frames on a roll are completely 'overexposed' but again also next to the exposed frame, than there is a sudden halt. (a straght line after wich everything looks normal, sometimes in the middle of a frame.)
In case it was only one side this could make sense, but it is two sides. (this happends about one every 4 films, while I use the same equipment the same way.
and my appologies for all these simple questions, I am just to damm curious
I am a relative beginner myself, so I will qualify my response with that statement. I have had issues of a purple cast on my negatives, and from my research, this is what I gathered:
No one seems to agree on what causes it 100%. The main school of thought is that it is a washing issue. Careful and thorough washing seems to be the answer. I found that with certain types of fixer I have had this problem more than with the Ilford Rapid Fix that I mainly use (Kodak recommends a herdener fixer for their B&W film, and I have had more purple cast with their fixer, even though I used the hypo clean afterwards).
The issue is, you mention spots... that is strange. It seems to be a case of some kind of impurity in your process - either the water, the containers you use? Perhaps some cross-contaminations from other chemicals? DO you use any detergent to wash out your tanks and reels? I strictly do not, but you probably already know this.
Everything else seems like a light leak - I know you say its not consistent, but Ihad a troublesome light leak that seemed to be coming on and off seemingly without any pattern. Turns out it was very slight, and in low light or indoors, I had no problems, the minute the camera went out at high noon or any bright, sunny day, I had issues. New foam fixed the problem (it was a 35 mm SLR). I am not fmiliar enough with the mechanicals of a hassy to be sure, but I wold look into it. Do you use a dark slide whenver handling your backs? I hope I don't offend you by my comments - I am not implying any incompetence - just going through alist of those obvious things that I know we all forget at one time or another, I know I have! Best luck,
One more thing - what type of reels do you use? I use the plastic Pattersons, and I find that I have to be particularily careful when cleaning them, as they tend to accumulate liquid in the grooves, and I found that I had some "artifacts" on the edges of my negs until I made sure the reels were thoroughly clean and dry before each use.
Hi Peter, thanks for your reply. I'll certainly look into some of the things you mentioned. (like the washing process)
But what do you mean with a dark slide?
I know that on the removeable backs, there is a metal plate that slides in (between the camera body and film back), protecting the front of the back (wow, that is a weird sentence...) from light exposure. I don't recall, not having had a hassy in hand in over a decade and a half(!), but I know that on some medium format cameras, like the Mamiya RB67, you can't remove the back without putting the dark slide in place. This may be a source of some of your troubles.
It is the proper term, "dark slide", as far as I know - soemone please correct me if I am givin Quinten the wrong info here.
If you've got spots I'd be suprised if it's washing. Cold water takes longer to wash but if you wash long enough it'll do the trick.
The film sounds underdeveloped if the Ilford writing is off. Unless Ilford had a problem with a batch of film but that's very unlikely.
Light leaks for the other problems.
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I think I get it, it's just the metal plate you slide into the filmback before removing it right? I have it in the back when I am not taking a picture, so it must happen somewhere once that slide is out.
Originally Posted by gnashings
I'll do some tests with the lenscap on and long exposures etc.
Light leaks I would say is the problem. I am going through the same thing with my RB67 back. My problem is the cover does not close properly (there is some play).
As for the faint negs I would have to agree with Nick Z. Sounds like under developing. Also try to be consistant with you temperatures. If your dev. is 20 degrees, make sure your stop,fix and wash water is also 20 D, +or- 3. Most of the lititure I have read say +-5 degrees but I try to match everything as close as possible usually within 1 d.
2 days ago I adjusted my dev.time as the room was warmer than normal. According to the Ilford temp adjusting table, I was to dev for 5 minutes at 23c instead of 6.5 minutes at 20c. I must have read the table wrong as my negs can out quite underdev. Don't know if I can use them, it's pretty bad.
If your gettting purple spots perhaps your fixer is not thourghly mixed? (I doubt this, but one never knows).
do fixer temps and times matter?
I am pretty accurate with the tempratures during development, as well as for the time, but does it matter what temp the stop bath and fixer are? I must say I don't pay to much attention to the time the fixer is in. As for stop baths and washing it's very hard to store so much water as needed for those things and bring at 20c. The water that comes out of my tap is about 12c
Originally Posted by rogueish
The risk is reticulation (grain clumping and emulsion cracking) the window of temperature change is 4deg F. If all your solutions are within 4deg F of eachother, you will not need to worry about this kind of damage. I have made this mistake myself and know these figures are correct from experience. - When the tap water for wash is far off (which it usually is here in Southern California) I fill the tank with tempered water and then let the wash water mix with and replace the water in the tank allowing for a gradual change. This has always worked for me as well.
My photos are always without all that distracting color ...
As for the light leaks on the Hasselblad backs what you need is to have the back serviced. There is a gasket that goes under the black plate that he back's serial number is on that need replacing. You can do it yourself but probably having it done is a better option, so that the rest of the back can be looked at as well.
To check for the light leak, take out the film magazine and the dark slide. Hold the back at eye level with the flat part facing up and the winding crank by your nose. Looking straight along down the flat part of the back, lift the end farthest from your nose up just very slightly. Slide the dark slide in about half an inch, then back out. Where the light leak probably is, is where the dark slide first shows up under the black plate (with the serial number on it). The dark slide has slowly worn away the gasket and now you have a light leak. If you hold it to the light you will probably see some daylight where the darkslide slides in.
If this is too confusing PMail me.
I couldn't think of anything witty to say so I left this blank.