photoflo or tween in VDB sensitizer

[davido]

hello

Is anyone using photoflo as a wetting agent in VDB or Kallitype sensitizer? Tween seems to the way to go;however, I've got a big bottle of photoflo handy. If there is anyone, how much do you add?

cheers
david

 

[Jim Noel]

I find no need for a wetting agent when coating VDB or kallitype. If I did, I would use a single drop of LFN when coating an 8x10.

I find that if I have sufficient sensitizer it coats very smoothly. If I try to skimp on the quantity in the hope of saving money, I waste more so I make sure I have an ample amount.

 

[Photo Engineer]

I've used photo flo 200 with no effect either way.

PE

 

[davido]

I'm having some bleeding problems (from the edges into the paper white areas) and was told that perhaps my sensitizer wasn't coating evenly and, thus, wetting agent would help. Sandy King suggested Everclear grain alchohol, which might be fun to have around the house (190 proof). Photoflo is just handier.
Jim, what is LFN?

david

 

[Jim Noel]

LFN is a surfactant packaged by Edwal which is a wetting agent far superior to Photo FLo in that it will not act as a catalyst if left to dry on film procesing reels. Also, its keeping qualities are unsurpassed.

 

[Photo Engineer]

LFN is a surfactant packaged by Edwal which is a wetting agent far superior to Photo FLo in that it will not act as a catalyst if left to dry on film procesing reels. Also, its keeping qualities are unsurpassed.

Jim;

"Catalyst"? Not sure what you mean here, but Photo-Flo 200 is a mixture of propylene glycol and a mild non-ionic surfactant. It is non-reactive to most all photographic materials even the raw emulsion.

It can dry on surfaces, just as any surfactant can, and leave a residue, and so must be washed off equipment with hot water. That is about it.

As for using it in VDB printing or evey Cyanotype, it merely helps spread the material on resistant paper surfaces. This is no more nor no less than other surfactants do. In fact, all commercial films and papers manufactured today contain some sort of surfactant.

PE

 

[Jim Noel]

I do not know about Photo FLo II, but I do know that about 15 years ago we had problems with overdevelopment along the edges of roll film on heavily used reels at the college. After the reels were scrubbed well and we switched to LFN we no longer had the problem. Perhaps the formula was different than it is currently, I don't know. However, LFN has been a very successful product for me and the college, so I do not use Photo Flo.

 

[davido]

I did try using photoflo II as a wetting agent for VDB and it wasn't alot of fun. I'm using a syringe to measure the amount of sensitizer; the Photoflo bubbles made it very difficult to read the amount. Then, when I went to slowly squeeze out the sensitizer onto the paper, the last 1/3 came exploding out and made a real mess. Ultimately, the Photoflo worked very well as a lubricant for the syringe but didn't seem to do any good for my paper.

david

 

[Russ Young]

I do not know about Photo FLo II, but I do know that about 15 years ago we had problems with overdevelopment along the edges of roll film on heavily used reels at the college. After the reels were scrubbed well and we switched to LFN we no longer had the problem.
Jim-
We had the exact experience when I taught at a large university in the 1980s. The switch to LFN solved the problem entirely. Before that, the darkroom tech had to clean tanks and reels on a regular basis.
Russ

 

[Loris Medici]

I did try using photoflo II as a wetting agent for VDB and it wasn't alot of fun. I'm using a syringe to measure the amount of sensitizer; the Photoflo bubbles made it very difficult to read the amount. Then, when I went to slowly squeeze out the sensitizer onto the paper, the last 1/3 came exploding out and made a real mess. Ultimately, the Photoflo worked very well as a lubricant for the syringe but didn't seem to do any good for my paper.

david

David,

You're likely addind too much of it. Try 1 drop per 10ml of sensitizer (with my pipettes, that makes 1 drop of PhotoFlo per 250 drops of sensitizer). If you use less than 10ml sensitizer, then dilute some PhotoFlo in a separate container so that the final strength doesn't change and you still add 1 drop.

For instance, if you are going coat using 2ml sensitizer, then you need 2/10 -> 1/5 drops of PhotoFlo. Perpare your 2ml sensitizer in a shot glass (using a syringe), put 1 drop of PhotoFlo and 4 drops (5 - 1) of distilled water in another, swirl and get it in a pipette, add 1 drop of this to your 2ml sensitizer container, swirl and get it in another pipette (do not use the syringe, you already measured the required amnt. of sensitizer!), draw / pour the sensitizer onto your paper and quickly use the rod (or brush) to spread it (don't wait too much since it will be absorbed quicker than you are used to). That's it! If that sounds too much complicated, then you can prepare a diluted PhotoFlo stock solution beforehand (refresh it often if you're not sure the keeping properties).

Hope this helps,
Loris.

 

[davido]

thanks Loris for the very good advice. I will give photoflo another chance. However, I'm finding that pre-coating the paper with plain distilled water is working quite well as far as increasing the amount of sensitizer the paper will absorb (in this somewhat dry environment) and consistent spreading.

david

 

[Loris Medici]

thanks Loris for the very good advice. I will give photoflo another chance. However, I'm finding that pre-coating the paper with plain distilled water is working quite well as far as increasing the amount of sensitizer the paper will absorb (in this somewhat dry environment) and consistent spreading.

david

Hi again David,

Use whatever method that works best for you. I always try to keep things as simple as possible. Adding wetting agent to the sensitizer is a complication (because you add another variable to your system), avoid this if you can solve it by implementing simplier solutions.

My remark about pre-coating paper with distilled water would be: this will make your paper more fragile therefore more vulnerable to abrasion. Thin papers may become bumpy / wavy and that is a problem if you use glass rods to coat the emulsion (its a problem also when you use brushes, because it may cause the sensitizer puddle). In short, this can cause your coating operation becoming more complicated; because your paper will be less tolerant to application errors.

Anyway. What counts is to have good results - using whatever method suits you best...

Bonne chance!
Loris.