Getting Clean Negs

[Gordon Wood]

I'm brand new to the forum. I must say, I'm very encouraged to see that there's a lot of activity here, indicating that LF photography may have a long life yet! I found the LF Home Page articles very helpful before making the recent plunge into 4x5, and am grateful for the guidance it has provided.

Now - to the subject at hand. Over the last several decades, I have done a lot of b&w neg processing (as well as one foray into Ektachrome). I've always been careful with cleanliness, temperature consistency, etc., but would be the first to admit that the results are often disappointing for one reason or another. Now that I'm starting to work with 4x5 (FP4 currently), I notice that tiny dust flecks embedded in the final negs are plentiful. I know this is nothing new, but I was wondering how most folks minimize it. Sadly, Digital Ice doesn't work with b&w at the scanning stage, so obviously I need to look at the processing stage.

I give the films a running water wash for 5-10 mins after fixing, then use a dunk in either Ilfotol or Photo Flo 200 and hang them in a nearly-closed file box to dry (if I close it completely, the film never dries). I recently got a film squeegee (w/rubber blades), but find it awkward to hold the film and get a consistent wipe across the whole sheet. Also, I'm concerned about scratching the emulsion. Are dust marks just something we just have to live with?

Since I'm still learning camera movements, I'll be sticking to b&w until I'm proficient. However, at some point, I'm going to want to try colour. Are there still a number of labs willing to process 4x5 chromes (I'm in Ontario, Canada)? What's the best way to package & ship the sheets to minimize the risk of damage?

Thanks in advance.
Gordon

[ic-racer]

Try mixing the Photo Flo in distilled or filtered water. Try a better place to dry. If the dust won't come off the negative, then it goat imbedded in the emulsion at the time of drying. Look for or build a better place to dry the negatives. Consider an air filter for the darkroom that runs when you are processing film. Especially during the time the film leaves the Photoflo and when it is hung up.

I'd not ever touch the wet emulsion with hands or anything else.

You should not get any dust imbedded in the emulsion. I have only had a few specs in the emulsion in from year to year. Maybe one spec per 20 to 50 sheets of 8x10. Of course, after the film is dry it can collect dust, but that dust can be removed (though it is not always easy, as it tends to re-settle, but thats another issue ).

One example of how to do it. Notice the HEPA air filter that sits on top of the drying cabinet. I turn it on when I start setting up for developing the film. By the time the film comes out of the drum, the air should be clean. Also, no sweaters allowed in the darkroom.

[Gordon Wood]

Thanks ic-racer. I did consider a HEPA filter - time to consider again! I noticed something alarming yesterday that I forgot to mention. The Photo Flo tends to precipitate on the bottom of the storage tank, creating floating flakes in the solution when disturbed. May not relate to dust specks, but something I'll now have to filter out.

[jeroldharter]

Another factor to consider is your film holders. Some film holders are very dusty. The film holder should be cleaned with a camel hair brush each time film is changed. The darkslides should be dusted on both sides. Be careful not to dust the holders and dark slides and then set them down on a dusty table or cloth. Likewise, when you remove the darkslide to expose the film, be careful about dust and if necessary give it a pass with a bristle brush before re-inserting it.

If you use a changing tent, vacuum the inside and wipe it down.

You should not store Photo-Flo. Put some in a dropper and use just a few (3-5) drops in an 8x10 tray. Put the film in photo-flo one sheet at a time emulsion side up. I don't use anything to wipe the surface of the film before drying - I just hang it by the corner like the photo above. A drying cabinet is ideal, again wiped clean on the inside and supplied by filtered air.

[Nathan Potter]

The whole image generating train should be taken as suspect. If you have particulates imbedded in the emulsion chances are they come from the developing process. So look at the following steps and procedures.

Install a 5 um or less filter in your water lines. Home Depot has em.
Wear a lint free labcoat in the processing area.
Better yet install a HEPA filter in the darkroom to scrub the air continuously.
Make sure your processing gear is clean of dust prior to use. Rinse off.
Make sure the negs are clean prior to developing.
Make sure solutions are precipitate free. May need to filter them.
Use HEPA filtered drying chamber. (See icy-racer setup)

HEPAs are your friend and can really pay off in dust reduction if you can employ them effectively. While they cost a bit of money and work they payoff big time in clean negatives.

Nate Potter, Austin TX.

[jp]

I have also found that clean storage of film holders in the field makes a big difference in dust prevention. They can easily pick up lint from your camera bag, paper, jacket, pants, etc... I have taken to storing them in antistatic (pink) ziplock style bags when they are not in the camera or darkroom.

In the darkroom for the photoflo rinse, I use either distilled water or alcohol. Tap water with possible impurities or dissolved material is not what I want drying on it. Some people are lucky and have much cleaner tap water than I.

[jeroldharter]

...
In the darkroom for the photoflo rinse, I use either distilled water or alcohol...

Do you just substitute isopropyl alcohol for water or mix the two?

[ic-racer]

Thanks ic-racer. I did consider a HEPA filter - time to consider again! I noticed something alarming yesterday that I forgot to mention. The Photo Flo tends to precipitate on the bottom of the storage tank, creating floating flakes in the solution when disturbed. May not relate to dust specks, but something I'll now have to filter out.

You should not store diluted photoflo. Mix->use->throw out
Track down a measuring syringe or pipette.

[CG]

... The Photo Flo tends to precipitate on the bottom of the storage tank, creating floating flakes in the solution when disturbed ...

Dump the photo flo after each session. No sense adding crud after all the washing's done. Photo flo's too cheap to worry about. I just use a half capful for a small tank and more for larger tanks.

[jeroldharter]

The Photographer's Formulary version of Photo-Flo comes in a nice container such that the lid pops up and you can deposit drops of solution into a tray.

http://stores.photoformulary.com/-st...ent/Detail.bok