I purchased this book by The Edwal Laboratories, Inc, 3rd Edition, 1947 at a camera store junk box still wrapped. What I find interesting are the tips that are given; and these tips have been around for 51 years or perhaps longer since the 1st Edition was published August 1939.

1. To test the "clearing time" of fixer, Edwal recommends that you soak a piece of negative film 3 to 4 minutes first before placing it into the fixer.

2. Use Edwal Kwik-Wet in the developer to prevent airbell holes.
:)

I purchased this book by The Edwal Laboratories, Inc, 3rd Edition, 1947 at a camera store junk box still wrapped. What I find interesting are the tips that are given; and these tips have been around for 51 years or perhaps longer since the 1st Edition was published August 1939.

1. To test the "clearing time" of fixer, Edwal recommends that you soak a piece of negative film 3 to 4 minutes first before placing it into the fixer.

Lots of posts on this subject on APUG: Several this week. Use the film leader or a ~ 1 inch piece cut from a roll (or sheet) of the film. With the room lights on, place the film strip in fresh fixer. With agitation, time how long it takes for the film to become completely transparent (or clear). This is the clearing time for this film/fixer combination. Multiply the clearing time by three for the total fixing time. Ideally, you should perform this clearing time test before each fixer use.
When the clearing time doubles the time determined by your initial clearing time test, discard the fixer.

2. Use Edwal Kwik-Wet in the developer to prevent airbell holes.
:)

I think their wetting agent is called Edwal LFN now. Be careful about presoaking film with a wetting agent - it may cause problems with some films.

I presoak with deionized water only at the same temperature as the developer.

Referring only to the fact that the tips have been around for years and not something that came about in the last 15-20 years. :)

I think their wetting agent is called Edwal LFN now. Be careful about presoaking film with a wetting agent - it may cause problems with some films.

I presoak with deionized water only at the same temperature as the developer.

What types of problems, Tom? I've used this without exception for over 4 years and with several types of films.

I think their wetting agent is called Edwal LFN now. Be careful about presoaking film with a wetting agent - it may cause problems with some films.

Although I don't presoak in anything but water, the tap type, it's clean here, I do use LFN in the developer, I have used it in every type of film and used it for at least three decades. My negatives are as good as it gets, never had an air bell or liquid adhesion problems. I use it in tanks, trays and deep tanks with hangers, all of my developer gets the solution. It's one of those items like Spotone that I need. Freestyle has been my source since the '70's.

It isn't recommended to put wetting agent in developers because with certain types of agitation, particularly inversion, it can lead to air-bells is you aren't very careful. Carry over of wetting agent from a pre-soak can do the same.

Ian

Hi Guys,

I have been getting air bells on the edges of my 4x5's. I am running them in my Phototherm using the 4x5 tubes.
Earlier last year i shaved the sides down with some sand paper and the problem is better but i still have these small areas of undeveloped film in the rebate area.
I was wondering if i could use a small amount of Photo Flo 200 in the developer (Tmax 1:5)?

Thanks
-ian