hi i have been having problems with vertical streaks on hp5+. using patterson system and ilford dev. should i prewet? agitate or not first 30-60 sec's? are some films more succeptable to this? never had problems with verichrome pan. also recently moved from nebraska to so cal. could it be the water? should i filter it? thanks for input

-- mike wilcox (mdwcox@aol.com), October 25, 1998

Answers

Well, it would be good to know what kind of streaks these are. Are they on the emulsion? Are they on the base? Are they steaks of varying contrast? Are the streaks lengthwise, or from side-to-side? ("Vertical" doesn't describe too much to me, sorry) Is this 35mm film, with the problem highly evident around the sprocket holes?

The reason I ask is because there are many different factors which will cause film to streak.

I have heard that there can be streaks caused by development "surges" as developer is poured into a daylight tank. (These streaks have never happened to me.) Prewetting would cure this. The only other way to get rid of this kind of streak is to fill the tank with developer first, and then quickly put in the film.

I have seen streaks on Agfa APX 25 caused by bad drying. It looks like a long line, or series of tiny pockmarks in the emulsion. Once those are in there, that's it, the film is permanently damaged. (caused by pro lab) If this seems evident on the film surface, you should try a drying agent, such as Kodak Photo Flo or Edwal LFN (with distilled water). One person around here espouses using just distilled water in the final wash.

I use filtered water for all of my processing. I have a small Pur filter mounted on my faucet. While using filtered or distilled water can be a good idea, I'm not sure that plain tap water would cause a streaking problem. Usually the problem with tap water is when it is way out of PH balance or very heavy or very light in mineral content. Then you will see a development problem.

Hope something here helps.

-- Brian C. Miller (a-bcmill@exchange.microsoft.com), October 26, 1998.

streaks

Its always a good idea to be filtering the water you are using, but that is not likly to be causing your problems. Developer streaking usualy is created at the beginning of the development process. A pre soak in water may help solve the problem (it will also change your total dev. time) but chances are that the cause is your initial agitation, it might be too vigirous. And if you continue to agitate in the same manner for the remainder of your time you will only aqdd to the problem. Submerging the film quickly into a tank of developer can actualy increase turbulance around the sprocket holes and add to the build up with improper agitation.

-- jim megargee (mvjim@interport.net), October 27, 1998.

PRE-SOAK

How does pre-soaking change the developing time?

-- Francis T. Knapik (fknapik@mail.nysed.gov), October 28, 1998.

I had a problem with surge marks on 35mm film developed in a small tank. Surge marks are streaks radiating from the sprocket holes in 35mm film in toward the center of the film. They are most obvious on even toned areas like sky or water. In my experience, they are not caused by pouring developer in, but by improper agitation technique. They appear most often if the tank is agitated solely by holding it in one hand and inverting it. I solved the problem for myself by giving the tank a twist each time it is inverted so that the developer moves sideways against the negative, and not just up and down. This is the technique recommended by St. Ansel in his books on darkroom technique. Since I started developing this way, no more surge marks.

-- Lee Goodwin (lgoodwin@thelenreid.com), November 20, 1998.

Francis;

Pre soaking increases developing time as it takes longer for the developer to replace the water already present in the emulsion. One minute increase is the rule of thumb.

-- Gene Crumpler (nikonguy@emji.net), November 20, 1998.