RA-4 chemistry and toxicity

[ericdan]

I print my color film in a make shift darkroom with a Nova slot processor next to my desk.
I can't help but notice how much more obvious the smell of the chemicals is. Especially the blix. (Ektacolor).
Are these chemicals a lot more dangerous than B&W ? Any other precautions I should take other than ventilation and Nitril gloves?

 

[Gerald C Koch]

Obviously you would not be inclined to drink them. Any danger would lie in skin contact or inhalation. What you are smelling from the blix is ammonia which can be irritating to the mucus membranes of the mouth, nose and throat. It would be best if you found some better means of ventilation or perhaps another location. The developing agent can cause skin irritation and blistering. It is also a suspected carcinogen. Wear nitrile gloves when working. If there is a chance of splatter then goggles or better a face shield would be recommended.

 

[mshchem]

The newer the process the less likely you are to (within reason ) hurt yourself. Look back when mercuric chloride, sodium cyanide, formaldehyde and chrome hardeners etc. Were in use. We have the miracle of disposable nitrile gloves, safety glasses, and great respirators . If you simply follow the instructions it's harmless. If you are bothered by the odor you need more ventilation and/or a proper 3M cartridge respirator.

Ask some of the folks about the old CP-5 print chemistry , used formaldehyde. Yecch!
The Nova system is probably one of the best in terms of odor.
My biggest complaint is more with black and white toners,fixes etc.
Happy printing, Mike

 

[Rudeofus]

While RA-4 CD can be nasty (CD-3 can trigger allergic reactions etc.), RA-4 BLIX is relatively mundane. The smell of RA-4 BLIX is not clearly Ammonia IMHO, although Ammonia may contribute to the overall bouquet of it. Its main ingredients are Ammonium Ferric EDTA (a dietary supplement), Ammonium Thiosulfate (present in most B&W fixers) and some form of sulfite (present in all B&W fixers).

All these RA-4 bathes are commercially used in open tanks, BTW, so their fumes can't be that toxic.

 

[ericdan]

that's what I thought. I've seen people work in dip and dunk labs without respirators. I assume even minilab machines such as the noritsu and frontiers must somehow give off this smell. In any case, I'll see if I can improve ventilation and get one of those 3M respirators.

 

[Wayne]

If you describe or show a picture of your workspace I'm sure people can help suggest creative and inexpensive ways to ventilate it. I process in open trays and hardly notice the smell. I have 2 muffin fans mounted in a piece of plywood fitted to the window 3 feet behind my sink. The whole thing probably cost $15-20.

 

[ericdan]

that would be embarrassing, but I guess I could do that.

 

[ericdan]

Behind the double curtain is an open balcony door. From the other side of the room I have a small fan blowing.

 

[mshchem]

That's a nice setup, I would like to add a Nova processor to my collection someday.

 

[Wayne]

Behind the double curtain is an open balcony door. From the other side of the room I have a small fan blowing.
View attachment 176525

Good you did it though. That's probably not going to be adequate. My first step would be to put the fan in that patio doorway and have it blowing out. You don't want air blowing from behind you toward the outside, you want it sucking air from the Nova and going directly out from there, without that air going past you. You should be on the far side of the Nova, like this order you-->Nova-->fan in door or window blowing out--> the outside

Depending on what is outside that door like streetlights, etc, you may need to be creative to block the light having the fan there too. I normally only print at night and I live in a rural area so I don't have to worry too much. But my fans are mounted in a (almost lol) light-proof box that fits into the storm window track and covers up that entire half of the window. The other half is covered with black visqueen. So I can print in the day if I have to.

 

[ericdan]

Thanks a lot Wayne. I could easily fit a window mounted fan like this into that balcony door behind the curtain.
The only problem would be how to make it light tight. I'd be interested to see your 'almost light-proof' solution.

Thanks,
Eric

 

[Wayne]

Unfortunately I don't have any pictures of mine and wont be able to get any for a long while, but maybe I can describe it. I took a sheet of 1/4 or 3/8 inch plywood the size of my storm window, so it fit snugly in the track. I mounted the muffin fans in it about 3/4 of the way up. I then built a shallow rectangular box as a light trap and mounted that to the outside of the sheet, covering the fans. This box is painted flat black inside, and has a slot a couple inches wide near the bottom for the exhaust to exit. So the air is forced out the window into the top of this box, and exits the slot at the bottom. I can easily take the whole thing in or out of the window. And like I said I cover the rest of the window with visqueen.

Its not a perfect design, but it works pretty well. I can think of a couple ways it could be improved. On a really bright winter day I can see some light reflecting off the flat black interior. An additional "corner" would eliminate this. I've thought of building a short hood over the exit slot that points downward, then light would have to come up into the hood, and turn a corner and then another corner. A strategically placed baffle or two inside the box might do the same thing, or a small hood on the inside that would cover the fans. That's probably a good idea anyway, to keep fingers and other objects from getting into the muffin fans.

Anyway you'll have to figure out what will work as a light trap for your fan, but you get the idea hopefully. Mine is very very simple. With the muffin fans being so small and powerful and the blades taking up nearly 100% of the fan openings, I don't think much if any air can be forced backward into the room by resistance in the light trap box. I sure don't notice any. But if you use a normal window fan you might want to think about that possibility and design the light trap accordingly so the exhaust encounters less resistance and doesn't back up.

 

[mklw1954]

Odor or smell does not necessarily mean toxicity but it indicates something is in the air and people's sensitivity to different chemicals in different concentrations vary. I seem to be a little sensitive to the RA4 developer but providing some ventilation, covering open bottles, and covering a "waste" bucket (used to highly dilute the spent chemicals prior to pouring down the sink) has eliminated that. Lab goggles and nitrile gloves are good common sense, inexpensive precautions too.