Mystery spots on negs. Need expert opinion.

[tonghang_zhou]

I'm having these tiny white spots on the images scanned

from B&W negatives that I developed myself. They show

up on many frames on every roll. The positions are

random and tend to cluster. They are ruinous to the

image quality, so I'd like to get help from more

knowledge folks to identify the cause of the problem.

 

Here's a sample (cropped by 10X): http://www.cicely.com/demo/spots.jpg

 

I can correspond the white spots in the scanned images

to black spots on the negatives. But they are very

barely visible even under a loupe.

 

I'm using Microphen (powder developer) on Tri-X and

HP5+, at speed or pushed to 500. Stock solution only one

day old. Times/temperature standard. Acid stop 30 sec.

Fixer 5 minutes, hypo-clear, 10 min rinse. This is

the first time I'm using powder developer, which I

mixed myself by instruction.

 

Dilution is 1+0 and 1+1. The more dilution case seems to

show fewer spots, but not conclusively.

 

Thanks a lot!

Tonghang.

[klix]

Undissolved powder particles...???

[jorge_oliveira2]

How clean is your water, specially the one used to mix and dillute developer?

 

Try it with distilled (or at leat filtered) water.

[conrad_hoffman]

You might try filtering your developer before use. A simple cotton ball (I steal 'em from my wife's dressing table) in a funnel will usually do the trick. Coffee filters work well, but are too slow for me.

[Troll]

I always think of undisolved hypo. It is worth running your chemicals through a coffee filter (one at a time) to see which if either) might be causing the problem. It might also be your plumbing.

[tom_menegatos]

What scanner are you using. Scanners that use an LED light source tend to pick up dust and such on negatives more than other types of light sources.

[tonghang_zhou]

Just filtered my remaining Microphen stock through a coffee filter. Definitely something in there. Now I see it makes a lot of sense. Diluted 1+1, there were fewer spots on average. The clustering effect was probably caused by agitation during development which must have made a undisolved developer spec move about in a small area (Is this how the liquid supposed to flow in a spiral tank? Either that or my agitation technique is lacking.)

 

If the new rolls I'll be doing next weekend are free of spots, then this has to be the reason.

 

I suppose the mixing instructions could mention filtering. Completely disolved stock seems rather unlikely.

 

Thanks so much!

[wclark5179]

I recommend that when you mix up any powder photo chemical into water that you do so in many stages. In other words, visually divide the powder into many parts. Mix a little bit of power into the water container, put on the lid, then invert several times until the water is pretty clear. Shaking can make the water cloudy. By inverting a clear container you can see if the powder has dissolved.<P>Do this little bit of power, mix, little bit of powder, mix until the entire contents are in your water.<P>If you pour all the powder in at once you'll have a difficult time getting it all to mix in the water.<P>I use Ilford products. Microphen is a fine developer for certain results. <P>The mix water should be 104 degrees which allows the powder to mix quiclky and thoroughly.<P>This may help with your spots. Get the developer mixed the first time and you don't have to be concerned with stray granules in your stock solution.<P>My Microphen stock solution is completely clear after mixing.<P>Hope this helps you.

[lex_jenkins]

"I suppose the mixing instructions could mention filtering."

 

Good point. I guess most of us who've used powdered chemistry for years have just learned to hard way to filter, unless we were lucky enough to have been coached to do so before we experienced problems.

 

For the manufacturers to suggest filtering would be to admit there's a potential problem. Unlikely to happen.

[frank.schifano]

Good advice about mixing the powdered chemicals into water a bit at a time, but you don't need to invert the container. I usually mix stock solutions by the gallon, so a small bucket and a plastic slotted spoon are the tools of choice for me. Filtering the final solution is not really necessary. Any remaining undissolved powder will usually go into solution in a few hours, so just mix your chemistry up ahead of time.

[jorge_oliveira2]

There had been some arguments about a need to mix chemicals 24Hs before using it.

 

Could this be the reson?